Tait TEL0038 Base Station Transmitter User Manual 8c300 a4 bk
Tait Limited Base Station Transmitter 8c300 a4 bk
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![M830-00T835 Initial Tuning & AdjustmentB3.5Copyright TEL 23/07/993.4 Short Tuning ProcedureUse this procedure only if you want to reprogram the receiver to a frequency outside the3MHz switching range and do not intend to carry out any other major adjustments orrepairs.3.4.1 IntroductionReprogram the operating frequency as described in the PGM800Win program-ming kit (refer to Section 3.2).Remove the top cover (nearest the handle).Set up the test equipment as described in Section 3.3.Set the links in the audio processor section as required (refer to Section 3.5).3.4.2 Synthesiser Alignment• Connect a high impedance voltmeter to PL4-1 or the junction of L1 & R1 in theVCO (this measures the synthesiser loop voltage).•Single Channel Tune VCO trimmer CV1 for a synthesiser loop voltage of9V.Multichannel Tune VCO trimmer CV1 for a synthesiser loop voltage of9V on the middle channel.If there is no middle channel, tune CV1 so that the chan-nels are symmetrically placed around a loop voltage of 9V.All channels should lie within the upper and lower limitsof 13V and 5V respectively.Do not attempt to program channels with a greater fre-quency separation than the specified switching range of3MHz.3.4.3 Front End AlignmentNote 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:For multichannel operation align the receiver on a frequency in the middleof the required band.Set RV230 (front panel gating sensitivity) fully clockwise.Inject a strong on-channel RF signal with ±3kHz deviation (±2.4kHz) [±1.5kHz] at](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-57.png)
![B3.6T835 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL1kHz into the antenna socket and adjust front end doublets L410, L420, L460 &L470 to give best sinad.Continually decrease the RF level to maintain 12dB sinad.Readjust L410, L420, L460 & L470 to give best sinad.With PL210 and PL220 connected for de-emphasised audio response, the receiversensitivity should be better than -117dBm, assuming that the audio levels are notbeing overdriven (refer to Section 3.4.5).3.4.4 Mute AdjustmentCarry out the one of the following sets of instructions according to the mute option youhave selected.3.4.4.1 Noise MuteConnect pins 1 & 2 of PL250 to enable the noise mute.Set the RF level to -105dBm with ±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Set RV230 (front panel gating sensitivity) fully anticlockwise.Adjust RV330 (noise mute gain) fully clockwise to close the mute (if necessaryturn off the RF signal and then turn it on again).Rotate RV330 anticlockwise until the mute just opens.Reset the signal generator for the required opening sinad and adjust RV230 clock-wise until the mute just opens.3.4.4.2 Carrier Level MuteConnect pins 2 & 3 of PL250 to enable the carrier mute and disable the noise mute.Apply an on-channel signal from the RF generator at the required mute openinglevel with ±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV235 (carrier mute) anticlockwise to close the mute (if necessary, momen-tarily turn off the RF), then slowly adjust it clockwise until the mute just opens.The mute should now open at this preset level.3.4.5 Line Amplifier OutputApply an on-channel signal from the RF generator at a level of -70dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV210 (front panel line level) to set the line level to the required outputlevel.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-58.png)
![M830-00T835 Initial Tuning & AdjustmentB3.7Copyright TEL 23/07/993.4.6 CTCSS3.4.6.1 Decoder OperationProgram a CTCSS tone on the set channel using PGM800Win.Set the RF signal generator output to -70dBm.Modulate the generator with both:• a 1kHz tone at ±3kHz deviation (±2.4kHz) [±1.5kHz];• and a CTCSS tone at the programmed frequency at ±500Hz deviation (±400Hz)[±300Hz].Check that the receiver gate opens and the front panel "Gate" LED is on.3.4.6.2 Opening SinadAdjust RV230 (front panel gating sensitivity) fully clockwise.Reduce the RF signal level to -110dBm.Observe the sinad meter and reduce the RF level until the receiver mute closes.Slowly increase the signal level until the receiver mute just opens and stays open.With PL240 pins 1 & 2 linked (high pass filter bypassed), check that the sinad isless than 6dB.Reset the signal generator for the required opening sinad, adjust RV230 fully anti-clockwise, then clockwise until the mute just opens.3.4.6.3 High Pass FilterSet the audio processor links as follows:Reset the RF signal generator output to -70dBm and note the line level (measure-ment A).Reduce the 1kHz generator to zero output and measure the line level again (meas-urement B).Check that measurement B is at least 30dB below measurement A.Plug Link FunctionPL210 1 - 2 de-emphasised responsePL230 2 - 3 audio from internal CTCSS speech filterPL240 4 - 5 audio input via PL230 or I/O pad](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-59.png)
![B3.8T835 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL3.4.7 RSSI (If Used)Align the receiver as instructed in Section 3.6 and Section 3.7.Apply an on-channel signal from the RF generator at a level of -100dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV320 (RSSI level) to give 4.5V RSSI output on pin 5 of D-range 1 (PL100)when measured with a high impedance DMM.3.5 Audio Processor Links3.5.1 GeneralUse the following table to set up the audio processor to the configuration you require.You should set the audio processor links before carrying out the receiver alignment.The factory settings are shown in brackets [ ].Plug Link FunctionPL210 [1 - 2]2 - 3 de-emphasised responseflat responsePL220 1 - 2[2 - 3] flat responsede-emphasised responsePL230aa. Refer to Section 3.5.2 for further details.1 - 2[2 - 3]3 - 4audio input via AUDIO-2 padaudio from internal CTCSS speech filteraudio input via I/O pad P250PL240a1 - 2[2 - 3]or3 - 44 - 5bypass high pass filter300Hz high pass filter in circuitaudio input via PL230 or I/O padPL250 [1 - 2]2 - 3 noise mutecarrier mutePL260bb. Refer to Section 1.4 in Part G for further details.1 - 2[2 - 3] RX-DISABLE linknot connectedPL270 [1 - 2]2 - 3 relay linknot connected](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-60.png)
![B3.10T835 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL3.6 Synthesiser Alignment• Ensure that the receiver has been programmed with the required frequenciesusing PGM800Win software.• Connect a high impedance voltmeter to PL4-1 or the junction of L1 & R1 in theVCO (this measures the synthesiser loop voltage).•Single Channel Tune VCO trimmer CV1 for a synthesiser loop voltage of9V.Multichannel Tune VCO trimmer CV1 for a synthesiser loop voltage of9V on the middle channel.If there is no middle channel, tune CV1 so that the chan-nels are symmetrically placed around a loop voltage of 9V.All channels should lie within the upper and lower limitsof 13V and 5V respectively.Do not attempt to program channels with a greater fre-quency separation than the specified switching range of3MHz.• The TCXO (IC700) output frequency should be trimmed when the IF is tuned -refer to Section 3.7.3.7 Alignment Of Receiver Front End And IFNote 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:Frequency Range136-156MHz: Check that links SL405 to SL440 and link B in the frontend are bridged with solder. 148-174MHz: Check that link A is bridged with solder and links SL405to SL440 and link B are not connected.VCO: The correct VCO is fitted at the factory. If you changethe operating frequency range of the receiver, make sureyou also fit the correct VCO for that frequency range.Align the synthesiser as instructed in Section 3.6. For multichannel operationalign the receiver on a frequency in the middle of the required band.Set RV230 (front panel gating sensitivity) fully clockwise.Inject a strong on-channel RF signal with ±3kHz deviation (±2.4kHz) [±1.5kHz] at1kHz into the antenna socket and adjust front end doublets L410, L420, L460 &L470 to give best sinad.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-62.png)
![M830-00T835 Initial Tuning & AdjustmentB3.11Copyright TEL 23/07/99Continually decrease the RF level to maintain 12dB sinad.Roughly tune IF coils L330/L340/L350, CV318 and quad coil L360 for best sinad.While maintaining a low level unmodulated RF input to the receiver, loosely cou-ple into the first IF an additional high level signal at 21.4MHz - you will hear abeat note.Trim the synthesiser TCXO (IC700) for zero beat.Note:If a second oscillator is not available, you can connect a frequency counter toIC710 pin 8 (i.e. after the TCXO buffer) via an oscilloscope probe to measurethe TCXO frequency directly (12.8MHz). At this point the voltage level isapproximately 4V p-p.Readjust L410, L420, L460 & L470 to give best sinad.Change the RF signal level to -75dBm and modulate with ±3kHz deviation(±2.4kHz) [±1.5kHz] at 1kHz.Connect an oscilloscope probe to the RSSI test point (TP310) and connect plugsPL210 and PL220 to give a flat audio response (refer to Section 3.5).Readjust IF coils L330/L340/L350, CV318 and quad coil L360 to give a maximumamplitude response on the oscilloscope with minimal amplitude modulation.Note:If you would like a more accurate method of tuning the IF, refer to the sweeptuning method described in Section 5.5.5.Further adjust these coils, along with L360, for minimum audio distortion, ensur-ing that the 455kHz level (on the oscilloscope) does not fall significantly.Check that the distortion reading is:wide bandwidth ≤2%mid bandwidth ≤4%narrow bandwidth ≤4%.Reconnect plugs PL210 and PL220 to give a de-emphasised audio response (ifrequired) and reduce the RF level until 12dB sinad is reached. The receiver sensi-tivity should be better than -117dBm, assuming that the audio levels are not beingoverdriven (refer to Section 3.11).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-63.png)
![B3.12T835 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL3.8 Gating DelayTwo solder links (SL210 & SL220) are provided on the bottom of the PCB to allow threegate delay time options, as shown in the table below.*Factory setting.3.9 Noise Mute AdjustmentConnect pins 1 & 2 of PL250 to enable the noise mute.Align the receiver as instructed in Section 3.6 and Section 3.7.Set the RF level to -105dBm with ±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Set RV230 (front panel gating sensitivity) fully anticlockwise.Adjust RV330 (noise mute gain) fully clockwise to close the mute (if necessaryturn off the RF signal and then turn it on again).Rotate RV330 anticlockwise until the mute just opens.Reset the signal generator for the required opening sinad and adjust RV230 clock-wise until the mute just opens.3.10 Carrier Level MuteConnect pins 2 & 3 of PL250 to enable the carrier mute and disable the noise mute.Apply an on-channel signal from the RF generator at the required mute openinglevel with ±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV235 (carrier mute) anticlockwise to close the mute (if necessary, momen-tarily turn off the RF), then slowly adjust it clockwise until the mute just opens.The mute should now open at this preset level.SL210 SL220 Closing Delaylinked not linked <50ms*not linked linked <25msnot linked not linked <20ms](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-64.png)
![M830-00T835 Initial Tuning & AdjustmentB3.13Copyright TEL 23/07/993.11 Audio Processor3.11.1 Line Amplifier OutputApply an on-channel signal from the RF generator at a level of -70dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV210 (front panel line level) to give an output of +10dBm on the 600 ohmline.Check for any clipping or distortion on the oscilloscope.Set the line level to the required output level.3.11.2 Monitor Amplifier Output (Speaker Output)Adjust RV205 (front panel monitor volume) to give an output of 2V rms into a 4ohm resistive load.Check for any clipping or distortion on the oscilloscope.Switch to a 4 ohm speaker and adjust RV205 to the required level.3.12 CTCSS3.12.1 Decoder OperationProgram a CTCSS tone on the default channel using PGM800Win.Set the RF signal generator output to -70dBm.Modulate the generator with both:• a 1kHz tone at ±3kHz deviation (±2.4kHz) [±1.5kHz];• and a CTCSS tone at the programmed frequency at ±500Hz deviation (±400Hz)[±300Hz].Check that the receiver gate opens and the front panel "Gate" LED is on.3.12.2 Opening SinadAdjust RV230 (front panel gating sensitivity) fully clockwise.Reduce the RF signal level to -110dBm.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-65.png)
![B3.14T835 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TELObserve the sinad meter and reduce the RF level until the receiver mute closes.Slowly increase the signal level until the receiver mute just opens and stays open.With PL240 pins 1 & 2 linked (high pass filter bypassed), check that the sinad isless than 6dB.Reset the signal generator for the required opening sinad, adjust RV230 fully anti-clockwise, then clockwise until the mute just opens.3.12.3 High Pass FilterSet the audio processor links as follows:Reset the RF signal generator output to -70dBm and note the line level (measure-ment A).Reduce the 1kHz generator to zero output and measure the line level again (meas-urement B).Check that measurement B is at least 30dB below measurement A.3.13 RSSIAlign the receiver as instructed in Section 3.6 and Section 3.7.Apply an on-channel signal from the RF generator at a level of -100dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV320 (RSSI level) to give 4.5V RSSI output on pin 5 of D-range 1 (PL100)when measured with a high impedance DMM.Plug Link FunctionPL210 1 - 2 de-emphasised responsePL230 2 - 3 audio from internal CTCSS speech filterPL240 4 - 5 audio input via PL230 or I/O pad](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-66.png)
![M830-00T835 Functional TestingB4.1Copyright TEL 23/07/994 T835 Functional TestingCaution:This equipment contains CMOS devices which are susceptible to dam-age from static charges. Refer to Section 1.2 in Part A for more infor-mation on anti-static procedures when handling these devices.The following test procedures will confirm that the T835 has been tuned and adjustedcorrectly and is fully operational.Note 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:Unless otherwise specified, the term "PGM800Win" used in this and follow-ing sections refers to version 2.00 and later of the software.Refer to Figure 4.3 for the location of the main tuning and adjustment controls, and toSection 3.3 for the test equipment set-up. Refer also to Section 6 where the parts lists,grid reference index and diagrams will provide detailed information on identifying andlocating components and test points on the main PCB. The parts list and diagrams forthe VCO PCB are in Part E.The following topics are covered in this section.Section Title Page4.1 Current Consumption 4.34.2 Sensitivity 4.34.3 Switching Range 4.34.4 Audio Distortion 4.44.5 Ultimate Signal-To-Noise Ratio 4.44.6 De-emphasised Audio Frequency Response 4.54.7 Noise Mute (If Linked In) 4.64.8 RSSI 4.64.9 Carrier Level Mute (Carrier Mute Linked In) 4.7Editor’s Note:The CTCSS adjustment procedures described in Section 4.10 havebeen moved to a more appropriate location in Section 3 as part ofthe Initial Tuning & Adjustment procedure (refer to Section 3.4.6and Section 3.12).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-67.png)
![M830-00T835 Functional TestingB4.3Copyright TEL 23/07/994.1 Current ConsumptionConnect the T835 to a 13.8V power supply.Rotate RV230 (front panel gating sensitivity) anticlockwise until the "Gate" LED isextinguished.Set switch SW201 (front panel monitor mute) to the on position.Check that the current in the 13.8V power cable is less than 350mA.Rotate the RV230 clockwise until the "Gate" LED is lit.Rotate RV210 (front panel line level) and RV205 (front panel monitor volume) togive maximum outputs.Check that the current is less than 800mA.Reset the front panel controls to the required settings.4.2 SensitivityIf CTCSS is enabled, disable the CTCSS tone by either programming the T835 for"No Tone" on the set channel, or by pulling pin 10 of D-range 2 (CTCSS ENABLE)low.Apply an on-channel signal from the RF generator with ±3kHz deviation(±2.4kHz) [±1.5kHz] at 1kHz.Adjust the RF level to give 12dB audio sinad.Check that the sensitivity is -117dBm or better.4.3 Switching RangeApply an on-channel signal from the RF generator at various frequencies withinthe 3MHz switching range (front end bandwidth), corresponding to pre-programmed channels.Measure the sensitivity at each frequency as described in Section 4.2.Ensure that the sensitivity is -115dBm or better across the whole switching range.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-69.png)
![B4.4T835 Functional TestingM830-0023/07/99 Copyright TEL4.4 Audio DistortionThe level of distortion measured at the line output (refer to Figure 1.3 in Part F) gives anindication of the accuracy of the IF alignment.Apply an accurate on-channel signal from the RF generator at a level of -70dBmwith ±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Adjust RV210 (front panel line level) to give +10dBm into 600 ohms.Check that the distortion is approximately 1% THD.Note:For a flat response, the distortion should always be better than 2% for widebandwidth sets or 4% for mid and narrow bandwidth sets.Adjust RV205 (front panel monitor volume) to give 2V rms into a 4 ohm resistiveload.Check that the distortion at the monitor output is better than 2% THD.Reset the controls before proceeding to the next set of tests.4.5 Ultimate Signal-To-Noise RatioApply a signal from the RF generator at a level of -57dBm with ±3kHz deviation(±2.4kHz) [±1.5kHz] at 1kHz.Select de-emphasis on the links provided in the audio processor (refer to Section3.5), and link pins 2 & 3 of PL240 to include the 300Hz filter.Adjust RV210 (front panel line level) to provide +10dBm output.Switch off the modulation, checking that the residual noise is lower than -45dBm(-43dBm) [-39dBm] at the line output (this corresponds to S/N of 55dB (53dB)[49dB] and is in accordance with EIA measurement conditions).Note:You can make the measurement without the 300Hz high pass filter, but theresult will be 10dB worse.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-70.png)
![B4.6T835 Functional TestingM830-0023/07/99 Copyright TEL4.7 Noise Mute (If Linked In)Rotate RV230 (front panel gating sensitivity) fully anticlockwise.Apply an on-channel signal from the RF generator at a level of -110dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Increase the RF level in 1dB steps, checking that the mute opens for an RF inputlevel of approximately -105dBm.Turn the RF off and check that the mute closes.Rotate RV230 clockwise and check that the mute opens.Reset RV230 to give the required opening sinad.Note:False opening of the mute can occur if the RF generator’s attenuator is noisywhen the level is being changed.4.8 RSSIApply an on-channel signal from the RF generator at a level of -100dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Using a high impedance DMM, check that the RSSI output voltage on pin 5 ofD-range 1 (PL100) is 4.5V (nominal).Vary the RF level in 5dB steps and check that the RSSI output voltage changes at arate of approximately 15dB/V over the range of -115dBm to -70dBm (refer to Fig-ure 4.2 for RSSI voltage vs signal strength).Figure 4.2 T835 RSSI Voltage vs Signal StrengthRF Level (dBm)-130 -120 -110 -100 -90 -80 -70 -6012345678RSSI Voltage](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-72.png)
![M830-00T835 Functional TestingB4.7Copyright TEL 23/07/994.9 Carrier Level Mute (Carrier Mute Linked In)Apply an on-channel signal from the RF generator at a level of -120dBm with±3kHz deviation (±2.4kHz) [±1.5kHz] at 1kHz.Increase the RF level in 2dB steps and check that the mute opens at an RF levelwhich corresponds with the preset level on RV235 (carrier mute), i.e. between-115dBm and -70dBm.Editor’s Note:The CTCSS adjustment procedures described in Section 4.10 havebeen moved to a more appropriate location in Section 3 as part ofthe Initial Tuning & Adjustment procedure (refer to Section 3.4.6and Section 3.12).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-73.png)
![M830-00T835 Fault FindingB5.1Copyright TEL 23/07/995 T835 Fault FindingCaution:This equipment contains CMOS devices which are susceptible to dam-age from static charges. Refer to Section 1.2 in Part A for more infor-mation on anti-static procedures when handling these devices.The following test procedures and fault finding flow charts may be used to help locate ahardware problem, however they are by no means a complete fault finding procedure.If you still cannot trace the fault after progressing through them in a logical manner,contact your nearest Tait Dealer or Customer Service Organisation. If necessary, you canget additional technical help from Customer Support, Radio Systems Division, Tait Elec-tronics Ltd, Christchurch, New Zealand (full contact details are on page 2).Note 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:Unless otherwise specified, the term "PGM800Win" used in this and follow-ing sections refers to version 2.00 and later of the software.Refer to Section 6 where the parts lists, grid reference index and diagrams will providedetailed information on identifying and locating components and test points on themain PCB. The parts list and diagrams for the VCO PCB are in Part E.The following topics are covered in this section.Section Title Page5.1 Visual Checks 5.35.2 Component Checks 5.35.3 Front Panel LED Indicator 5.35.45.4.15.4.25.4.3DC ChecksPower RailsVCO LockingMute Operation5.45.45.45.45.55.5.15.5.25.5.35.5.3.15.5.3.25.5.45.5.5RF ChecksVCO FrequencyRF SensitivityOscillator StabilityTCXOSecond IFDemodulator OutputIF Distortion5.55.55.55.65.65.65.65.7](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-75.png)
![B5.6T835 Fault FindingM830-0023/07/99 Copyright TELNote:Poor sensitivity into the mixer can be caused by lack of drive level from theVCO (the drive level should be >+17dBm).Refer to the receiver fault finding charts (Section 5.7.6) for further information.5.5.3 Oscillator Stability5.5.3.1 TCXOWhile maintaining a low level unmodulated RF input to the receiver, loosely cou-ple into the first IF an additional high level signal at 21.4MHz - you should nowhear a constant low frequency beat note.Tap the TCXO with a finger and replace it if the beat note permanently changes.5.5.3.2 Second IFWhile maintaining a low level unmodulated RF input to the receiver, loosely cou-ple into the second IF an additional high level signal at 455kHz - you should nowhear a constant low frequency beat note.Adjust the frequency of the 455kHz signal for zero beat.If the second IF is more than 300Hz off frequency, check IC340, X310, C345 andC347 and replace if necessary.5.5.4 Demodulator OutputApply an on-channel RF signal modulated by 1kHz with ±3kHz (±2.4kHz)[±1.5kHz] deviation at an amplitude of -65dBm.Connect an oscilloscope probe (DC coupled) to IC350 pin 7 (audio output).Check that an audio signal of approximately 380mV peak to peak is present.With the audio response set to flat, optimum tuning of the quad coil (L360) for mini-mum audio distortion should coincide with maximum audio amplitude and a DC levelof approximately 1.3V.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-80.png)
![M830-00T835 Fault FindingB5.7Copyright TEL 23/07/995.5.5 IF DistortionIf the audio distortion is still high after careful IF alignment (Section 3.7), sweep the IF toinvestigate the bandpass response.Apply an on-channel RF signal modulated at 10Hz (sine wave) with approxi-mately ±12kHz (±9kHz) [±6kHz] deviation at an amplitude of -80dBm.Connect the modulating 10Hz audio signal to the "X" input of an oscilloscope andobserve the 455kHz IF input to IC350 pin 16 via a suitable RF probe on the "Y"input. Alternatively, use an oscilloscope probe for the "Y" input to monitor theRSSI output voltage at TP310 (RSSI test point) or pin 5 of D-range 1 (PL100). Thiswill give a demodulated log response and only the top half of the wave formsshown in Figure 5.2 and Figure 5.3 will be displayed on the oscilloscope screen.Note:The X input should be DC coupled.Check that the swept response has a rounded top and no sharp non-linearities(refer to Figure 5.2).Increase the RF level to -50dBm; the trace will now show the shape of the 455kHzceramic filter (&XF340).Check that the response has no sharp non-linearities.If sharp non-linearities do occur, replace the filter and sweep again to confirm asatisfactory solution (refer to Figure 5.3).Figure 5.2 IF Swept Response Figure 5.3 Ceramic Filter Swept Response](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-81.png)
![B5.16T835 Fault FindingM830-0023/07/99 Copyright TEL5.7.4 Noise MuteApply on channel signal@ -117dBm* to receiver.Refer to audiofault finding chart.Ensure PL250 is setfor noise mute operation.Audio onIC350 pin 7?Noise onIC390 pin 7?Amplified noiseon C395? Check Q340& Q350.Check D310 isrectifying noise.Vary RF level &observe voltageon pad 236.Pad 236 voltagevaries 0-1.8V?Check 9V rail &resistors R264,R265 & R284.Replace IC270.Check/replaceIC270 & D240.Replace Q250.NYNYNYYNYYYYNRefer toreceiver faultfinding chart.Check componentsaround active filter.Mutable audioon outputs?YVoltage varies0-2.5V?NOKDoes "Gate" LEDtoggle on/off?NCheck Q230, Q245 &Q290 for operation.YAdjust RV230(gating sensitivity)& observe voltageon IC270 pin 3.Set RF signal level to-117dBm. RotateRV230 c/w & cc/w.Monitor voltage onIC270 pin 1. Switching0-8V as RV230 rotated?Monitor voltage onIC270 pin 7. Switching0-8V as RV230 rotated?Monitor voltage onpad 234. Switching0-8V as RV230 rotated?NNNDoes "Gate"LED toggle? Check/replaceQ255 & D250.YYNCheck RV330adjustment(noise mute gain).Approx. 0.6V DC rect-ified noise on pad 236?NSwitch SW201 (monitormute) to ensuremute is enabled.Rotate RV230(gating sensitivity)c/w & cc/w & view"Gate" LED.Note:c/w = clockwisecc/w = counterclockwise or anticlockwise*Modulated by 1kHz signal with ±3kHz (±2.4kHz) [±1.5kHz] deviation](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-90.png)
![M830-00T835 Fault FindingB5.17Copyright TEL 23/07/995.7.5 Carrier Mute Approx. 5V onRSSI pad 238?Approx. 5V onIC280 pin 1?Check IC390 andadjoining components.Check/replace IC280& adjoining components.Check Q230, Q245 &Q290 for operation. Adjust RV235 &observe voltageon IC280 pin 6.Switch SW201(monitor mute) to ensuremute is enabled.YNNNYYDoes "Gate" LEDtoggle on/off?Check for short circuitsand/or replace IC350.Refer to receiver faultfinding chart.NNYYVoltage varies0-6V?Check 9V rail &resistors R275,R277 & RV235.YNSet RF signal levelto -95dBm. RotateRV235 c/w & cc/w.Monitor voltage onIC280 pin 7. Switching0-8V as RV235 rotated? Replace IC280.NYMonitor voltage onIC270 pin 7. Switching0-8V as RV235 rotated?Check/replaceIC270 & D240.NYMonitor voltage onpad 234. Switching0-8V as RV235 rotated? Replace Q250.NYDoes "Gate"LED toggle? Check/replaceQ255 & D250.YNMutable audioon outputs?OKNYRefer to audiofault finding chart.Note:c/w = clockwisecc/w = counterclockwise or anticlockwiseRotate RV235(carrier mute) c/w & cc/w& view "Gate" LED.Ensure PL250 is setfor carrier mute operation,and the RSSI PCB is fitted.Apply on channel signal@ -95dBm* to receiver.Audio onIC350 pin 7?Approx. 3.3V onIC350 pin 5?*Modulated by 1kHz signal with ±3kHz (±2.4kHz) [±1.5kHz] deviation.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-91.png)
![M830-00T835 Fault FindingB5.19Copyright TEL 23/07/995.7.7 Audio Audio onIC350 pin 7?Audio onIC210 pin 1? Check componentsaround IC210.Apply on channel signal@ -117dBm* to receiver.Refer toreceiver faultfinding chart.Ensure RV230(gating sensitivity)fully clockwise."Gate" LED on? Refer to mutefault finding charts.YNNYNYNYAudio onspeaker?Audio onC238/C259?Audio onIC240 pin 2 &IC260 pin 2?Replace C249 &check continuity.Audio on linemonitor (pad 284)& line output?Refer to mutefault finding charts.OKCheck/replaceoutput components.NYNYNYNYAudio attop of RV205& RV210?Check C233 &PL240 link.Replacefaulty IC.*Modulated by 1kHz signal with ±3kHz (±2.4kHz) [±1.5kHz] deviation.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-93.png)
![M830-00T836/837 General InformationC1.11Copyright TEL 23/07/991.2.4.2 Modulation CharacteristicsFrequency Response .. flat or pre-emphasised (optional) (below limiting)Line And Microphone Inputs: Pre-emphasised Response- Bandwidth .. 300Hz to 3kHz (WB & MB).. 300Hz to 2.55kHz (NB)Below Limiting .. within +1, -3dB of a 6dB/octavepre-emphasis characteristic Flat Response .. within +1, -2dB of output at 1kHzAbove Limiting Response .. within +1, -2dB of a flat response(ref. 1kHz)Distortion .. 2%Hum And Noise: Wide Bandwidth .. -55dB (300Hz to 3kHz [EIA]) typical Mid Bandwidth .. -54dB (CEPT)Narrow Bandwidth .. -50dB (CEPT) Compressor (optional): Attack Time .. 10ms Decay Time .. 800ms Range .. 50dB1.2.4.3 CTCSSStandard Tones .. all 37 EIA group A, B and C tonesplus 13 commonly used tonesFrequency Error .. 0.08% max.(from EIA tones)Generated Tone Distortion .. 1.2% max.Generated Tone Flatness .. flat across 67 to 250.3Hz to within 1dBModulation Level .. adjustableModulated Distortion .. <5%1.2.5 MicrocontrollerAuxiliary Ports:Open Drain Type .. capable of sinking 2.25mA via 2k2ΩVds max. .. 5V](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-127.png)
![M830-00T836/837 Circuit OperationC2.9Copyright TEL 23/07/992.5.3 Keying InputsThere are four ways to key the exciter: • pulling the Tx-Key line low (pin 13 on D-range 1 [PL100]) at the rear of the set);• pushing the "Carrier" button on the front panel - this will inhibit all audio;• using the PTT button on the local microphone, disabling audio from the line;• via the opto-key inputs (pins 11 and 12 on D-range 1 [PL100]) when electricalisolation is required. This features a constant current sink (Q270) to ensure reli-able activation of the opto-coupler (IC250) at low keying voltages.2.5.4 Compressor (Automatic Level Control (ALC))The input signal is fed via a current controlled attenuator (Q230, Q220) to a high gainstage (IC230) from which the output signal is taken. This signal is passed to a compara-tor (IC230) which toggles whenever the audio signal exceeds a DC threshold deter-mined by RV220. Thus, the comparator produces a square wave whose mark-spaceratio is determined by the amplitude of the audio signal. This square wave pumps upthe reservoir capacitor (C233) which controls the attenuator (Q230, Q220), thus complet-ing the feedback loop.The compression level is set by adjustment of the comparator threshold (RV220).Note:Although the high dynamic range of the compressor allows the use of verylow audio signal levels, such conditions will be accompanied by a degrada-tion of the signal-to-noise ratio. Very low audio input levels should there-fore be avoided where possible.2.5.5 Outputs To ModulatorsThe output signal from the limiter (IC210, IC230) is added with a CTCSS tone at a sum-ming amplifier (IC260). The signal is then low pass filtered (IC260) and split to supplythe two modulators.Since the VCO modulator is a true frequency modulator, its audio is simply buffered(IC260). The reference modulator, however, is a phase modulator and its audio mustfirst be integrated (IC210).It is vital that the audio levels to the modulators are accurately set, relative to eachother. Hence the inclusion of level adjustment in the reference modulator path. Onceset, adjustments to absolute deviation may be made only by IC220, a 256-step 10k elec-tronic potentiometer (EPOT), which is controlled via PGM800Win. The EPOT is madeup of 256 resistive sections (representing approximately 39Ω each) which can be indi-vidually addressed by the microcontroller. Each section can be switched in or out of cir-cuit to achieve the required total resistance, thus adjusting the absolute deviation level.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-141.png)
![C3.6T836/837 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL3.4.4 Two Point Modulation AdjustmentNote 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:The reference modulation and limiter adjustments are controlled by 256-step electronic potentiometers (EPOTs), which are adjusted via the “Refer-ence Modulation” and “Deviation” settings in PGM800Win. This allows thetwo point modulation and deviation settings to be adjusted for each chan-nel.Note 3:To optimise the modulation response across the switching range, repeatsteps 1-4 below for each channel that will be used (usually needed only fordata applications). In applications where the modulation response is lesscritical (e.g. voice use only), carry out steps 1-4 below on the middle channeland use the “EPOT Fill” option1 in PGM800Win to copy the value to theother channels.1. Inject an audio signal of 600Hz 1.5V rms (+5dBm) into the CTCSS input (D-range1 (PL100) pin 8). Key the transmitter by earthing the Tx-Key line.2. Adjust the output from the audio generator to obtain ±3kHz (±2.4kHz) [±1.5kHz]deviation at 600Hz.3. Change the input frequency to 120Hz and, using PGM800Win, adjust the value ofthe “Reference Modulation” EPOT setting for the current channel to obtain ±3kHz(±2.4kHz) [±1.5kHz] deviation (you can use either the mouse or up and downarrow keys).4. Change the input frequency back to 600Hz.Repeat steps 2 and 3 above until the deviations achieved at the two input frequen-cies are within 0.2dB of each other. You will need to do this at least four times.5. Sweep the audio between 50 and 300Hz for peaks.Note:A peak between 50 and 300Hz will indicate a fault condition, i.e:- incorrect set-up or - modulation circuitry fault. The specification window is ±1dB relative to 150Hz from 65 to 260Hz.1. Use the “EDIT FILL” button on the tool bar or go to “Edit”, “Fill”, “Epot Settings” on the menu bar.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-152.png)
![M830-00T836/837 Initial Tuning & AdjustmentC3.7Copyright TEL 23/07/993.4.5 CTCSS Encoder (If Used)Program a CTCSS tone on the default channel using PGM800Win.If you are using an RF test set, turn off the 300Hz high pass filter.Key the T836/837 with the front panel "Carrier" switch.Adjust RV805 (CTCSS level adjust) to give ±500Hz (±350Hz) [±250Hz] deviation.Set the maximum deviation as per Section 3.4.6.3.4.6 FM Deviation (Limiter) AdjustmentNote:If the T836/837 will be used over the whole 8MHz switching range, youmust set the deviation for each channel. However, if the module will beused on frequencies that cover only a 1MHz (or less) switching range, youcan set the deviation on the middle channel and use this value for all otherchannels with the “EPOT Fill” option in PGM800Win.Inject 1kHz at -10dBm into the line input (D-range 1 (PL100) pins 1 & 4; pins 2 & 3shorted; refer to Section 2.2 of Part F).Adjust RV210 (line sensitivity) fully clockwise and key the transmitter by earthingthe Tx-Key line. Using PGM800Win, adjust the value of the “Deviation” EPOTsetting for the current channel to obtain a deviation limit of ±4.7kHz (±3.8kHz)[±2.3kHz] (you can use either the mouse or up and down arrow keys).Sweep the audio frequency from 100Hz to 4kHz and ensure that the maximumdeviation does not exceed ±4.7kHz (±3.8kHz) [±2.3kHz]. Readjust “Deviation” ifnecessary via PGM800Win.3.4.7 Line-in Level AdjustmentRemove the CTCSS signal (if used).Set the injected signal at the line input to the required line level (typically -10 to-20dBm).Adjust RV210 (line sensitivity) to provide ±3kHz (±2.4kHz) [±1.5kHz] deviation.Reapply the CTCSS signal (if required).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-153.png)
![C3.8T836/837 Initial Tuning & AdjustmentM830-0030/04/98 Copyright TEL3.5 Audio Processor Links3.5.1 Link DetailsUse the following table to set up the audio processor to the configuration you require.You should set the audio processor links before carrying out any of the tuning andadjustment procedures. The factory settings are shown in brackets [ ].3.5.2 Typical OptionsPlug Linkaa. The letters in this column and in the table in Section 3.5.2 below refer to the identificationletters screen printed onto the PCB beside each pair of pins.FunctionPL2051-2[3-4]5-6ABCnot connectedmicrophone pre-amp. output to compressor inputmicrophone pre-amp. output to multiplexer inputPL210[1-2]3-45-6LMNmultiplexer output to pre-emphasis inputmultiplexer output to limiter inputmultiplexer output to compressor inputPL2151-2[3-4]5-67-89-10GHIJKnot connectedcompressor output to multiplexer inputcompressor output to limiter inputcompressor output to pre-emphasis inputnot connectedPL2201-2[3-4]5-6DEFpre-emphasis output to multiplexer inputpre-emphasis output to limiter inputnot connectedPL205 PL210 PL215 PL220microphone pre-amp. compressedand pre-emphasised;line input pre-emphasised(standard set-up)[3-4]B[1-2]L[3-4]H[3-4]Emicrophone pre-amp. compressedand pre-emphasised;line input unprocessed3-4B3-4M7-8J1-2Dline and microphone compressedand pre-emphasised5-6C5-6N7-8J3-4Emicrophone pre-amp. compressed;line and microphone flat response3-4B3-4M3-4H5-6F](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-154.png)
![M830-00T836/837 Initial Tuning & AdjustmentC3.11Copyright TEL 23/07/993.9 Audio Processor & CTCSS3.9.1 Two Point ModulationThe T836 and T837 utilise two point modulation to obtain a wide audio bandwidthindependent of the synthesiser loop filter response. This is achieved by simultaneouslyfrequency modulating the VCO and phase modulating the synthesiser reference fre-quency. The relative signal levels fed to the two modulators are quite critical and causeinteraction when setting up.Both modulating signals require readjustment when the exciter is shifted in frequencygreater than the switching range (i.e. ∆F>±4MHz).Note 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:The reference modulation and limiter adjustments are controlled by 256-step electronic potentiometers (EPOTs), which are adjusted via the “Refer-ence Modulation” and “Deviation” settings in PGM800Win. This allows thetwo point modulation and deviation settings to be adjusted for each chan-nel.Note 3:To optimise the modulation response across the switching range, repeatsteps 1-4 below for each channel that will be used (usually needed only fordata applications). In applications where the modulation response is lesscritical (e.g. voice use only), carry out steps 1-4 below on the middle channeland use the “EPOT Fill” option1 in PGM800Win to copy the value to theother channels.3.9.2 Modulator Adjustment1. Inject an audio signal of 600Hz 1.5V rms (+5dBm) into the CTCSS input (D-range1 (PL100) pin 8). Key the transmitter by earthing the Tx-Key line.2. Adjust the output from the audio generator to obtain ±3kHz (±2.4kHz) [±1.5kHz]deviation at 600Hz.3. Change the input frequency to 120Hz and, using PGM800Win, adjust the value ofthe “Reference Modulation” EPOT setting for the current channel to obtain ±3kHz(±2.4kHz) [±1.5kHz] deviation (you can use either the mouse or up and downarrow keys).4. Change the input frequency back to 600Hz.Repeat steps 2 and 3 above until the deviations achieved at the two input frequen-cies are within 0.2dB of each other. You will need to do this at least four times.1. Use the “EDIT FILL” button on the tool bar or go to “Edit”, “Fill”, “Epot Settings” on the menu bar.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-157.png)
![C3.12T836/837 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TEL5. Sweep the audio between 50 and 300Hz for peaks.Note:A peak between 50 and 300Hz will indicate a fault condition, i.e:- incorrect set-up or - modulation circuitry fault. The specification window is ±1dB relative to 150Hz from 65 to 260Hz.3.9.3 CTCSS Encoder (If Used)Program a CTCSS tone on the default channel using PGM800Win.If you are using an RF test set, turn off the 300Hz high pass filter.Key the T836/837 with the front panel "Carrier" switch.Adjust RV805 (CTCSS level adjust) to give ±500Hz (±350Hz) [±250Hz] deviation.Set the maximum deviation as per Section 3.9.4.3.9.4 Limiter AdjustmentNote:If the T836/837 will be used over the whole 8MHz switching range, youmust set the deviation for each channel. However, if the module will beused on frequencies that cover only a 1MHz (or less) switching range, youcan set the deviation on the middle channel and use this value for all otherchannels with the “EPOT Fill” option in PGM800Win.Set the links in the audio processor section as required (refer to Section 3.5).Inject 1kHz at -10dBm into the line input (D-range 1 (PL100) pins 1 & 4; and pins 2& 3 shorted; refer to Section 2.2 of Part F).Adjust RV210 (line sensitivity) fully clockwise and key the transmitter by earthingthe Tx-Key line. Using PGM800Win, adjust the value of the “Deviation” EPOTsetting for the current channel to obtain a deviation limit of ±4.7kHz (±3.8kHz)[±2.3kHz] (you can use either the mouse or up and down arrow keys).Sweep the audio frequency from 100Hz to 4kHz and ensure that the maximumdeviation does not exceed ±4.7kHz (±3.8kHz) [±2.3kHz]. Readjust “Deviation” ifnecessary via PGM800Win.3.9.5 Line Level Without CompressorThis section assumes that the compressor is not used. If the compressor is required,refer to Section 3.9.6.Remove the CTCSS signal (if used).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-158.png)
![M830-00T836/837 Initial Tuning & AdjustmentC3.13Copyright TEL 23/07/99Adjust the line sensitivity as follows: • set the injected signal at the line input to the required line level (typically -10 to-20dBm);• adjust RV210 (line sensitivity) to provide ±3kHz (±2.4kHz) [±1.5kHz] devia-tion.Reapply the CTCSS signal (if required).3.9.6 CompressorThe compressor may be used on the line input only, the microphone input only, or onboth the line and microphone inputs. If the compressor is used, refer to one of the fol-lowing sections as appropriate.3.9.6.1 Compressor On Line Input OnlySet RV210 (line sensitivity) fully clockwise and key the transmitter by earthing theTx-Key line.Reduce the line level to -50dBm at 1kHz and set RV220 (compression level) fullyclockwise.Check that ±3kHz (±2.4kHz) [±1.5kHz] deviation is still available.Slowly increase the audio input level until the demodulated waveform shows sig-nificant signs of clipping (approximately ±4.5kHz (±3.6kHz) [±2.3kHz] deviation).Adjust RV220 anticlockwise until the demodulated waveform is just clipping(approximately ±4kHz (±3.2kHz) [±2kHz] deviation).Increase the input level to -10dBm and check that the test tone is still held just intoclipping. The input line level should be typically -10 to -20dBm.3.9.6.2 Compressor On Microphone Input OnlyKey the transmitter by earthing the Tx-Key line and plug a microphone jack intothe front panel socket.Adjust RV220 (compression level) fully clockwise.Acoustically couple the microphone to a tone box (1kHz) and close the PTTswitch.Increase the audio level until the demodulated waveform shows significant signsof clipping (approximately ±4.5kHz (±3.6kHz) [±2.3kHz] deviation).Adjust RV220 anticlockwise until the demodulated waveform is just clipping(approximately ±4kHz (±3.2kHz) [±2kHz] deviation).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-159.png)
![C3.14T836/837 Initial Tuning & AdjustmentM830-0023/07/99 Copyright TELIncrease the audio level by 10dB and verify that the test tone is held just into clip-ping.Whistle steadily into the microphone, checking that approximately ±4kHz(±3.2kHz) [±2kHz] deviation is produced. The modulated waveform should bebasically sinusoidal.Speak into the microphone, checking that the modulation peaks reach about±5kHz (±4kHz) [±2.5kHz] deviation.As the line is to be used without compression, set RV210 (line sensitivity) asdescribed in Section 3.9.5.3.9.6.3 Compressor On Both Line & Microphone InputsSet up as described in Section 3.9.6.1.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-160.png)
![M830-00T836/837 Functional TestingC4.1Copyright TEL 23/07/994 T836/837 Functional TestingCaution:This equipment contains CMOS devices which are susceptible to dam-age from static charges. Refer to Section 1.2 in Part A for more infor-mation on anti-static procedures when handling these devices.The following test procedures will confirm that the T836/837 has been tuned andadjusted correctly and is fully operational.Note 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:Unless otherwise specified, the term "PGM800Win" used in this and follow-ing sections refers to version 2.00 and later of the software.Refer to Figure 4.4 and Figure 4.5 for the location of the main tuning and adjustmentcontrols, and to Section 3.3 for the test equipment set-up. Refer also to Section 6 wherethe parts lists, grid reference index and diagrams will provide detailed information onidentifying and locating components and test points on the main PCB. The parts listand diagrams for the VCO PCB are in Part E.The following topics are covered in this section.Section Title Page4.1 Current Consumption 4.34.2 Output Power 4.34.3 Output Frequency 4.34.4 Timers 4.34.5 Frequency Response 4.44.6 Audio Level Input Sensitivity 4.7Editor’s Note:The CTCSS adjustment procedure described in Section 4.7 has beenmoved to a more appropriate location in Section 3 as part of the Ini-tial Tuning & Adjustment procedure (refer to Section 3.4.5 and Sec-tion 3.9.3).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-161.png)
![C4.4T836/837 Functional TestingM830-0023/07/99 Copyright TELFigure 4.1 T836/837 Transmit Timers4.5 Frequency ResponseIf the T836/837 has been correctly adjusted, the pre-emphasis and limiting responsesshould closely match those shown in Figure 4.2 and Figure 4.3 respectively. Note:The limits shown on these graphs should not be exceeded. • If you are using an RF test set, turn off all filters.• Measure the pre-emphasis response as follows: Reduce the line level to give ±1kHz (±0.8kHz) [±0.5kHz] deviation at 1kHz. Sweep the modulation frequency. The response should closely match that shown in Figure 4.2.• Measure the limiting response as follows: Set the line level to give ±3kHz (±2.4kHz) [±1.5kHz] deviation at 1kHz. Timer Function AdjustmentTransmit Tail Sets the tail time during which the transmitter stays keyed after the exter-nal key source has been removed.0-5 seconds in 100ms stepsaa. Adjustable in 20ms steps in PGM800Win version 2.12 and later.Transmit Timeout Sets the maximum continuous trans-mission time. Once the timer has timed out, the transmitter must be keyed again, unless prevented by the transmit lockout timer.0-300 secondsb in 10 second stepsb. Adjustable from 0 to 600 seconds in PGM800Win version 2.12 and later.Transmit Lockout Sets the period of time that must elapse after a timeout before the trans-mitter can re-transmit. Once the timer has timed out, the transmitter can be keyed again.0-60 seconds in 10 second stepsOnLockout TimeTimeoutTimeOnTail TimeTx-EnableTx-Reg.Tx-EnableTx-Reg.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-164.png)
![M830-00T836/837 Functional TestingC4.7Copyright TEL 23/07/994.6 Audio Level Input Sensitivity• Adjust RV210 (line sensitivity) fully clockwise.• Check that the input sensitivities are better than those specified below:Note:A degraded signal to noise ratio can be expected with the compressorselected. The extent of the degradation is dependent on the audio inputlevel.Line Input 600 ohms, ±3kHz (±2.4kHz) [±1.5kHz] deviation at 1kHz: with compressor -50dBm without compressor -30dBmMicrophone Input 600 ohms, ±3kHz (±2.4kHz) [±1.5kHz] deviation at 1kHz: with compressor -75dBm without compressor -55dBmCTCSS Input 1kHz deviation at 150Hz 500mV rmsEditor’s Note:The CTCSS adjustment procedure described in Section 4.7 has beenmoved to a more appropriate location in Section 3 as part of the Ini-tial Tuning & Adjustment procedure (refer to Section 3.4.5 and Sec-tion 3.9.3).](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-167.png)
![M830-00T836/837 Fault FindingC5.1Copyright TEL 23/07/995 T836/837 Fault FindingCaution:This equipment contains CMOS devices which are susceptible to dam-age from static charges. Refer to Section 1.2 in Part A for more infor-mation on anti-static procedures when handling these devices.The following test procedures and fault finding flow charts may be used to help locate ahardware problem, however they are by no means a complete fault finding procedure.If you still cannot trace the fault after progressing through them in a logical manner,contact your nearest Tait Dealer or Customer Service Organisation. If necessary, youcan get additional technical help from Customer Support, Radio Systems Division, TaitElectronics Ltd, Christchurch, New Zealand (full contact details are on page 2).Note 1:In this and following sections deviation settings are given first for widebandwidth sets, followed by settings in brackets for mid bandwidth sets ( )and narrow bandwidth sets [ ].Note 2:Unless otherwise specified, the term "PGM800Win" used in this and follow-ing sections refers to version 2.00 and later of the software.Refer to Section 6 where the parts lists, grid reference index and diagrams will providedetailed information on identifying and locating components and test points on themain PCB. The parts list and diagrams for the VCO PCB are in Part E.The following topics are covered in this sectionSection Title Page5.1 Visual Checks 5.35.2 Component Checks 5.35.3 Front Panel LED Indicator 5.35.45.4.15.4.2DC ChecksPower RailsVCO Locking5.45.45.45.55.5.15.5.25.5.35.5.4RF ChecksT836 Drive PowerT836 PA Output PowerT837 Output PowerAudio And Modulation5.55.55.55.55.65.6 PGM800Win Generated Errors 5.7](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-169.png)
![C5.6T836/837 Fault FindingM830-0030/04/98 Copyright TELConnect the exciter output to a power meter and key the exciter.Check that the output power is between 600 and 1000mW.Note:If the synthesiser is out of lock, the lock detector (synthesiser IC740 andcomparator IC750) will prevent the RF signal from reaching the PA byswitching the supply to the exciter amplifier (Q340, Q345).5.5.4 Audio And ModulationRefer to the audio processor fault finding chart (Section 5.7.7).Set up the audio processor as described in Section 3.9.Check that the demodulated RF output has the frequency response referred to inSection 4.5 with at least ±5kHz (±4kHz) [±2.5kHz] deviation available at 1kHzmodulating frequency.If the above result is not achieved, either the two modulators are incorrectly adjusted ora fault condition exists.](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-174.png)
![G1.2T835 Link Selectable FeaturesM830-0030/04/98 Copyright TEL1.6 300Hz High Pass FilterLink PL240 also allows the insertion of this filter to improve hum and noise perform-ance.1.7 Audio Processor LinksThe tables in this section are the same as those in Section 3.5 in Part B. They have beenrepeated here for ease of reference.1.7.1 GeneralUse the following table to set up the audio processor to the configuration you require.You should set the audio processor links before carrying out the receiver alignment.The factory settings are shown in brackets [ ].*Refer to Section 1.7.2 for further details.Plug Link FunctionPL210 [1 - 2]2 - 3 de-emphasised responseflat responsePL220 1 - 2[2 - 3] flat responsede-emphasised responsePL230* 1 - 2[2 - 3]3 - 4audio input via AUDIO-2 padaudio from internal CTCSS speech filteraudio input via I/O pad P250PL240*1 - 2[2 - 3]or3 - 44 - 5bypass high pass filter300Hz high pass filter in circuitaudio input via PL230 or I/O padPL250 [1 - 2]2 - 3 noise mutecarrier mutePL260 1 - 2[2 - 3] RX-DISABLE linknot connectedPL270 [1 - 2]2 - 3 relay linknot connected](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-324.png)
![M830-00T836/837 Optional FeaturesG2.1Copyright TEL 30/04/982 T836/837 Optional Features2.1 Audio ProcessorThe T836 and T837 come with a number of link selectable features which give addedsystem flexibility. Note:The tables in this section are the same as those in Section 3.5 in Part C. Theyhave been repeated here for ease of reference.2.1.1 Link DetailsUse the following table to set up the audio processor to the configuration you require.You should set the audio processor links before carrying out any of the tuning andadjustment procedures. The factory settings are shown in brackets [ ].Plug Linkaa. The letters in this column and in the table in Section 2.1.2 below refer to the identificationletters screen printed onto the PCB beside each pair of pins.FunctionPL2051-2[3-4]5-6ABCnot connectedmicrophone pre-amp. output to compressor inputmicrophone pre-amp. output to multiplexer inputPL210[1-2]3-45-6LMNmultiplexer output to pre-emphasis inputmultiplexer output to limiter inputmultiplexer output to compressor inputPL2151-2[3-4]5-67-89-10GHIJKnot connectedcompressor output to multiplexer inputcompressor output to limiter inputcompressor output to pre-emphasis inputnot connectedPL2201-2[3-4]5-6DEFpre-emphasis output to multiplexer inputpre-emphasis output to limiter inputnot connected](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-327.png)
![G2.2T836/837 Optional FeaturesM830-0030/04/98 Copyright TEL2.1.2 Typical Options2.2 Line Transformer Inputs And OutputsThe line transformer (T210) is designed to provide a balanced interface to 600 ohm lines.For normal operation the two centre connections (LINE I/P 2, LINE I/P 3) are shortedtogether, and the 600 ohm line is connected between LINE I/P 1 and LINE I/P 4.The secondary winding of the transformer is connected via 1k and 10Ω (R160) resistorsto pin 6 (AUDIO-2) of D-range 1 and may be used to monitor audio on the line. Pin 7 ofD-range 1 can be reconfigured as AUDIO-1 by removing R808 and R160, and placing%R150 (refer to Section 2 in Part I for more details).2.3 Opto KeyThe keying circuitry may be completely isolated from the rest of the system by means ofthe optocoupler (IC250) connected between pins 11 and 12 of the D-range connector. Aconstant current source (Q270) allows keying voltages between 6 and 50V.2.4 Relay DriverA dedicated transistor (Q250) is provided for the purpose of switching an external (e.g.coaxial) relay. The output is open collector and is activated by the Tx-reg rail. This out-put is available on pin 9 of the T800-03-0000 auxiliary D-range connector (D-range 2).PL205 PL210 PL215 PL220microphone pre-amp. compressedand pre-emphasised;line input pre-emphasised(standard set-up)[3-4]B[1-2]L[3-4]H[3-4]Emicrophone pre-amp. compressedand pre-emphasised;line input unprocessed3-4B3-4M7-8J1-2Dline and microphone compressedand pre-emphasised5-6C5-6N7-8J3-4Emicrophone pre-amp. compressed;line and microphone flat response3-4B3-4M3-4H5-6F](https://usermanual.wiki/Tait/TEL0038.Manual/User-Guide-120349-Page-328.png)
