Tokyo Hy Power Labs HL-550FX 550W HF LINEAR AMPLIFIER User Manual

Tokyo Hy-Power Labs, Inc. 550W HF LINEAR AMPLIFIER Users Manual

Users Manual

    Users Manual Solid-State HF/50MHz Band 550W Linear Power Amplifier Model HL-550FX
1 1. Introduction  Thank you for purchasing the HL-550FX. This compact and lightweight desktop HF linear power amplifier has a maximum input power of 1.2kW. Our solid-state broadband power amp technology makes it the smallest and lightest in the industry in its class. Typical output power is 550W (SSB, CW) with the drive power of 65-90W. It is best suited for the DX-pedition use due to its light and compact design.   2. Cautions  2-1 The amplifier is cooled by forced airflow. Several inches of clearance on the top and the rear wall are necessary to allow for smooth air intake into the fan. Do not block the air vents on the top cover.  2-2 Keep the amplifier out of direct sunlight, in a cool dry environment.  2-3 Internal high voltages (AC, DC and RF), are present at all times, ON AIR or OFF. Internal access should be limited to avoid injury.  2-4 Turn off the AC main power immediately upon any unusual sounds, sights, or odors.  Check  the  multimeter  readings  of  Vd  and  Id,  the  fuses  and  all  cable connections around the amplifier. Please notify the dealer or the factory of any problems.  2-5 For  your  safety,  do  not  operate  the  amplifier  without  adequate  grounding.  A proper  ground  connection  will  result  in  peak  performance  and  stability,  in addition to reduced RF strays or noises.  2-6 To  eliminate  the  RF  interference  to  such  home  appliances  as  TV,  FM  radio, telephone  sets,  and  etc.,  it  is  recommended  that  clamp-on  ferrite  cores  be inserted at both ends of the remote control cable, ALC cable, coaxial jumper cable, and antenna cables, as needed. Also, a common mode AC line filter (near the AC outlet), and in-line low pass filters on the antenna coaxial cable (as necessary), are recommended.
2 2-7 The  amplifier  has  fast  acting  sophisticated  protection  circuits.  Please  note, however, any such actions that cause the same fault to occur repeatedly, will lead to failure of the valuable final power FET transistors.  2-8 Before checking inside the amplifier, be sure to wait a few minutes for the high DC voltage to discharge (monitor Vd meter reading). The potentiometers for RF power  detector,  protection  circuits,  FET  bias  voltage  circuit,  etc.,  are  precisely adjusted  at  the  factory,  and  should  not  be  altered.  Doing  so,  would  require readjustment with precision measuring instruments.  2-9 The  DC  power  supply  section  consists  of  most  efficient  and  sophisticated switching  mode  circuit.  It  accepts  the  wide  AC  line  voltages  ranging  from  AC 100V up to 260V. Since the line voltage is detected  and selected  automatically, you  do  not  have  to  worry  about  the  tap  change  of  internal  power  transformer whichever  country  you  will  travel.  Be  sure  to  verify  capacity  of  AC  line  fuse before you plug the AC power cord into the outlet.  2-10 Before starting the amplifier, be sure to connect a dummy load (50 ohms, 550W min.) or a well-adjusted antenna to the output terminal. Operating without any load  will  cause  extreme  stress  to  the  RF  power  FET’s,  although  protection circuits should work under critical conditions.  2-11 Required drive power is slightly less than 100W to obtain the full 550W output. Do not attempt to operate with excessive drive from a high power transceiver.  2-12 Keep the  aluminum  heat  sink  and  air  openings free  from  dust  and  blockages. Periodic cleaning will prevent degraded cooling efficiency.  2-13 For long continuous operation in RTTY/FM modes, it is recommended that you reduce the RF drive levels by 20% to 30% lower output than CW/SSB modes.  2-14 To  prevent  damage  to  the  precision  electronic  components,  avoid  extreme physical shock to the amplifier. If factory service is required, the amplifier should be shipped using the original box and packing materials.
3 3. Features  3-1 Our solid-state broadband design engineers worked to make the HL-550FX, the lightest  and  most  compact  550W  out  portable  HF/50MHz  amplifier  in  the industry. This world-class compact  550W HF amplifier  is the easiest  to handle and operate anywhere in the world.  3-2 The  amplifier’s  main  PA  section  includes  4  high  power  MOS  FET  VRF150, resulting  in  550W  (SSB/CW  max.)  on  HF  and  50MHz  bands.  The  amplifier’s broadband characteristics require no further tuning once the operating band is selected.  3-3 The amplifier allows operation in full break-in CW mode due to the  use of the amplifier’s high-speed antenna relays (made by Panasonic).  3-4 With  the  unique  duct  structure  design  and  the  powerful  blower  fan,  the aluminum  heat  sink  block  for  RF  PA  module  (and  other  components),  are effectively  cooled.  The  fan’s  quiet  operation  allows  for  even  the  weakest  DX signals to be heard.  3-5 The amp utilizes a sophisticated circuit to run the various high speed protection circuits such as overdrive, high antenna SWR, DC overvoltage, band miss-set etc.  3-6 This amplifier is compatible with wide AC line voltage ranging from AC 100V to 260V. Although AC line voltage is automatically selected, be sure to install proper fuse into AC line fuse holder.  3-7 For the safety of the operator, an Interlock system is employed. The AC power is shut  down  if  the  top  cover  is  removed,  and  the  automated  safety  interlock  is activated.  3-8 An analog multimeter allows the operator to monitor Pf (Forward output power), Pr (Reflected power), Vd (Drain voltage of power FET), Id (Drain current) etc.
4 4. Specifications   Frequency Band  1.8~50 MHz all amateur bands including WARC bands Mode  SSB, CW (RTTY) RF Drive  65~90W typ. (100W max.) Output Power  550W typ. (RTTY 400W max.) Drain Voltage  42V Drain Current  30A max. Input Impedance  50Ω  (unbalanced) Output Impedance  50Ω  (unbalanced) Final Transistor  VRF150 x 4 Circuit  Class AB parallel push-pull Cooling Method  Forced Air Cooling Output Power  Pf 1kW Reflected Power  Pr 100W Drain Voltage  Vd 60V Multi-meter (F.S.) Drain Current  Id 50A Input/Output Connectors UHF SO-239 AC 200~260V, 50/60Hz 7.5A max. AC Power AC 100~130V, 50/60Hz 15A max. AC Consumption  1.3kVA max. when TX Dimension  232 x 145 x 392 mm, 9.1 x 5.7 x 15.4 inches (WxHxD) Weight  Approx. 9.2kgs. or 20.3lbs. Accessories  AC Power Cord x 1 Coax Jumper Cable (with PL259’s) x 1 RCA Plug x 2 Spare Fuse 8A x 2 (for AC200V line) Spare Fuse 15A x 2 (for AC100V line) Spare Fuse 15A x 2 (for F202, F203 of PC1662V power amp board) Spare Fuse 1A x 1 (for PC1662V power amp board) (miniature fuse) Spare Fuse 3.2A x 1 (for PC1819 sub AC control board) (miniature fuse) Users Manual
5 5. AC Line Voltage  5-1  Although the amplifier is designed to work with both AC 115V (100-130V) and AC 230V (200-260V), for stability we recommend operation from AC 230V.  5-2  The correct AC plug (not included in the package) must be obtained locally due to the AC plug variations worldwide.  5-3  The AC line fuse has been factory preset for 115V use (or as requested by the customer at the time of order). If you wish to change to AC 230V, change the fuse to 8A. For your safety, before making this change, be sure to pull the AC plug from the AC outlet to avoid injury.   NOTICE  Please note the followings when you are using AC100V line (AC100V~120V).  NEVER EXCEED OUTPUT POWER OF 500W, WHEN RUNNING THE AMP FROM AC100~120V LINE.  Otherwise,  over-current  protection  completely  shuts  down  the  drain  voltage  power supply for five minutes before it gets resettable.  When this protection works, O.DRIVE lamp lights and HL-550FX will enter the through state, the reset of the amp being disabled for five minutes.    To restart the amp, turn the POWER switch OFF, and wait for 5 (five) minutes. Then turn the power ON.  If the protection works too often, please take one or all of the following measures.  ①  Lower the drive power of the transceiver. ②  Connect the ALC line. Adjust the ALC Output Adjustment Knob on the rear panel so that the drain current (ID) will never exceed 25.0A on any frequency. ③  Change to AC200~240V line.
6 6-A. Front Panel Description  PPPPOOOOWWWWEEEERRRROOOOFFFFFFFFSSSSTTTTBBBBYYYYOOOOPPPPEEEERRRR.... OOOONNNN AAAAIIIIRRRR OOOO....DDDDRRRRIIIIVVVVEEEEOOOO....VVVVOOOOLLLLTTTTFFFFUUUUSSSSEEEE OOOO....HHHHEEEEAAAATTTTPPPPRRRRBBBBAAAANNNNDDDDMMMMEEEETTTTEEEERRRRPPPPRRRROOOOTTTTEEEECCCCTTTTFFFFAAAANNNNIIIIDDDDFFFFXXXXMMMMOOOODDDDEEEELLLLTTTTOOOOKKKKYYYYOOOO HHHHYYYY----PPPPOOOOWWWWEEEERRRRSSSSOOOOLLLLIIIIDDDD SSSSTTTTAAAATTTTEEEE LLLLIIIINNNNEEEEAAAARRRR AAAAMMMMPPPPLLLLIIIIFFFFIIIIEEEERRRR11112222 3333 44445555 6666 7777888899991111000011111111111122221111333311114444HHHHLLLL555555550000  ①①①①POWERPOWERPOWERPOWER  : Main power switch to turn AC power on and off. ②②②②POWER POWER POWER POWER (LED)(LED)(LED)(LED)  : Green LED lights when power is turned on.   ③③③③OPEROPEROPEROPER....  : OPERATE/STAND-BY switch. At OPERATE, the amplifier is ready to go into ON AIR (TX) mode and at STBY, it is on STAND-BY mode. ④④④④ON AIRON AIRON AIRON AIR    (LED)(LED)(LED)(LED)  : Green LED lights when the amplifier is in transmit (TX) mode. ⑤⑤⑤⑤O.DRIVEO.DRIVEO.DRIVEO.DRIVE    (LED)(LED)(LED)(LED) :  When overdrive or band miss-set  is detected, LED lights to indicate the protection circuit has worked. ⑥⑥⑥⑥PRPRPRPR    (LED)(LED)(LED)(LED)     :  LED  lights  when  reflected  power  from  antenna  exceeds  70W  to indicate protection circuit has worked. ⑦⑦⑦⑦O.VOLTO.VOLTO.VOLTO.VOLT    (LED)(LED)(LED)(LED)     : When the DC drain voltage of the FET (Vd) is too high, the LED lights to indicate the protection circuit has worked. ⑧⑧⑧⑧FUSFUSFUSFUSEEEE    (LED)(LED)(LED)(LED)     : LED lights when the 15A glass fuse has blown from excessive Id. (Two fuses are on the PC1622V PA board.)
7 ⑨⑨⑨⑨O.HEATO.HEATO.HEATO.HEAT    (LED)(LED)(LED)(LED)    : When the PA module temperature reaches 80 deg.C, the LED lights to indicate  the  protection  circuit  has  worked.  (It  is  necessary  for  the cooling fan to operate for several minutes to cool the PA module.) (Turn the main POWER switch to off, and then on again to reset the Protection Circuits.)(Turn the main POWER switch to off, and then on again to reset the Protection Circuits.)(Turn the main POWER switch to off, and then on again to reset the Protection Circuits.)(Turn the main POWER switch to off, and then on again to reset the Protection Circuits.)    ⑩⑩⑩⑩BANDBANDBANDBAND     : Select the desired operating frequency band. ⑪⑪⑪⑪METERMETERMETERMETER     : To change the multi-meter scales. Meter reads Pf, Pr, Vd, and Id. ⑫⑫⑫⑫ID ID ID ID (LED)(LED)(LED)(LED)     : LED lights when the input drain current is over 20A. This does not mean that any damage occurred to the amplifier, but is useful for the user to notice any stress influencing the final FET caused by high drain current, load impedance trouble, etc. We recommend that you note the usual  condition  of  the  lighting.  When  any  unusual  symptoms  are noticed, the user may lower the drive power from the transceiver, check the antenna SWR, etc. ⑬⑬⑬⑬FAN FAN FAN FAN (LED)(LED)(LED)(LED)     :  LED  lights  when  fan  is  running  at  high  speed.  When  the  heatsink reaches 50℃  the cooling fan will switch to high-speed mode to cool the heatsink. ⑭⑭⑭⑭MULTIMETERMULTIMETERMULTIMETERMULTIMETER     :  Pf  (Forward  output  power),  Pr  (Reflected  power  from  antenna),  Vd (FET drain voltage), and Id (FET drain current) are shown on the scale as selected by  ⑪METER select switch.
8 6-B. Rear Panel Description AAAALLLLCCCCAAAALLLLCCCC AAAADDDDJJJJSSSSTTTTBBBBYYYYGGGGNNNNDDDDAAAANNNNTTTTAAAACCCCFFFFUUUUSSSSEEEEIIIINNNNPPPPUUUUTTTT ⑭⑭⑭⑭AC POWERAC POWERAC POWERAC POWER     :  AC  Mains  Socket.  Socket  for  the  AC  power  cord.  (Socket  is  EMI filtered.) ⑮⑮⑮⑮STBYSTBYSTBYSTBY  : RCA Jack. Connect the control cable from the ACC terminal (or SEND, TX  GND  etc.)  of  the  transceiver.  The  center  pin  is  to  be  shorted  to ground  through  the  relay  circuit  of  the  transceiver.  The  DC  current necessary is 5V, 1mA only. ⑯⑯⑯⑯ALCALCALCALC     : RCA Jack for ALC Voltage Output. Negative DC voltage appears at the center  pin,  which  is fed  back  to  the  ALC  terminal  of  the  transceiver. ALC is used to keep the amplifier output power at certain limits. Also it is useful when the transceiver output power is higher than 100W. (See  page  12,  8.ALC  Connection).  Also  consult  your  HF/50MHz transceiver’s user manual. ⑰⑰⑰⑰GNDGNDGNDGND     : Ground Terminal ⑱⑱⑱⑱ALC ADJALC ADJALC ADJALC ADJ     : Potentiometer to adjust ALC voltage level. Minus 10V is available at maximum, when turned full counter-clockwise. Factory setting is 0 volts, with the pot turned full clockwise. ⑲⑲⑲⑲FUSEFUSEFUSEFUSE  : A pair of fuses for AC mains. 15A glass pre-installed fuse. (Change to 8A fuses if 230V line is used.) ⑳⑳⑳⑳ININININ    PUT (TX)PUT (TX)PUT (TX)PUT (TX)  :  RF  Input  Connector.  Connect  the  coax  jumper  cable  from  the transceiver. ○○○○21212121ANT ANT ANT ANT (OUTPUT)(OUTPUT)(OUTPUT)(OUTPUT) : RF Output Connector. Connect the coax cable to the antenna.
9      Inner Layout ofInner Layout ofInner Layout ofInner Layout of HL HL HL HL----550550550550FXFXFXFX     Upper ViewUpper ViewUpper ViewUpper View      ①  RF Power Detector and Send-Receive Switching Relay ②  Inter-lock Switch ③  LPF Board ④  Main Power Source Unit ⑤  Sub-Power Source Unit ⑥  Control Board ⑦  Power Amp Unit ⑧  Frequency Detector Board ⑨  Cooling Fan ⑩  AC Fuse
10 7. Connection and Operation  This section explains a one-antenna system connected to the transceiver and an external SWR/POWER meter.    7-1 Connect  AC  cord  and  coax  cables  as  illustrated  above.  Connect  the  cable from “SEND”  to  ACC  or  the  remote  terminals  of  transceiver,  where  it  is  marked “SEND” or “TX GND”. These terminal pins are shorted to the ground when the transceiver  is  in  TX/ON  AIR  mode.  If  these  connections  are  not  made,  the amplifier will not go into TX (amplification) mode. For a temporary check to the amp, ground the STBY center pin by inserting an RCA plug whose center pin has been soldered to the outer case of the plug with a small piece of wire.  7-2 At first, turn the ALC knob full clockwise to avoid ALC voltage being fed to the transceiver. Application of ALC will be covered in the following Section 8. ALC CONNECTION.  7-3 Keeping the POWER (AC mains) switch off, check the SWR of your antenna by keying the transceiver to TX mode (CW or RTTY mode). Monitor the SWR with an  external  SWR/Power  meter.  If  SWR  is  1.5  or  higher  at  band  center,  the AAAALLLLCCCC AAAANNNNTTTT((((SSSSEEEENNNNDDDD,,,,TTTTXXXX GGGGNNNNDDDD))))AAAACCCCCCCCIIIINNNNPPPPUUUUTTTTAAAANNNNTTTTSSSSTTTTBBBBYYYYAAAALLLLCCCCAAAACCCCTTTTXXXXAAAANNNNTTTTTTTT RRRR AAAA NNNN SSSS CCCC EEEE IIII VVVV EEEE RRRRAAAA NNNN TTTT EEEE NNNN NNNN AAAAHHHH LLLL ---- 1111 .... 1111 KKKK FFFF XXXX RRRR EEEE AAAA RRRR SSSS IIII DDDD EEEESSSS WWWW RRRR //// PPPP OOOO WWWW EEEE RRRR MMMM EEEE TTTT EEEE RRRRKKKKFFFFXXXXRRRREEEEAAAARRRRSSSSIIIIDDDDEEEEKKKKFFFFXXXXRRRREEEEAAAARRRRSSSSIIIIDDDDEEEE HLHLHLHL----550FX REAR SIDE550FX REAR SIDE550FX REAR SIDE550FX REAR SIDE
11 antenna has to be adjusted for lower SWR. As an alternative, an antenna tuner may be inserted.  7-4 Turn  the  POWER  switch  on.  Turn  the  BAND  switch  to  a  desired  operating frequency band. Turn the STAND-BY switch to OPER (operate) position and the amplifier  is  ready  to  go.  If  you  key  the  transceiver  with  the  carrier  level  set relatively low (such as 20-30W), you will achieve an amplified output signal of a few hundred watts. Monitor this output with the multimeter (at the Pf position) or with an external power meter. Increase drive level to roughly 50W and see if the  antenna SWR stays  constant. (As  higher RF  currents flow, some antennas may  show  a  changed  SWR  value  due  to  heated  connector  junctions  and  trap coils.)  7-5 You  can  now  increase  the  drive  level  to  nearly  80-90W  to  achieve  maximum carrier  output  power  of  550W  (CW)  from  the  amplifier.  If  you  change  to  SSB mode, average voice power of a few hundred watts will be observed on the panel meter, Pf scale, while peak voice power reaching a little over 550W. For high duty cycle transmissions like RTTY mode, it is recommended that you reduce the drive power by some 30%.  7-6 With  a  high  power  transceiver  in  SSB  mode,  you  can  overdrive  the  amplifier resulting in a distorted output signal. This can occur if you speak too loud or if you  set  the  microphone  gain  too  high.  Speak  into  the  microphone  properly  to reduce the possibilities of splattering into the neighborhood. The ALC is effective in preventing the output signal from being distorted or to limit the carrier level to within rated output levels. It is strongly recommended to make ALC connection, especially when 200W out high power radio is used to drive.  7-7 Protection circuits may work during operation depending on the conditions. If the protection circuit has shut down the amplifier, check the antenna SWR, Vd, AC line voltage, or try to reduce the drive level. To reset, turn off the POWER switch once, then back on again. The power transformer has an overheat protection in the coil layer. If this temperature switch activates, the amplifier will put you in receive mode with the cooling fan operating until the transformer has cooled off. It may take ten to fifteen minutes to cool, depending upon room temperature. For more details on this protection circuit, see Section 9. PROTECTION CIRCUITS.
12 8. ALC Connection  ALC voltage is available at the terminal marked ALC (RCA phono jack) on the right lower corner of the rear panel. Negative maximum DC voltage of ten volts (-10V) is produced at this terminal when the amplifier is fully driven. This voltage is adjustable with the ALC ADJ.  knob  located  above  the  ALC  jack.  Setting  ALC  voltage  properly  fed  back  to  the transceiver, we recommend you to keep the maximum output power constant or hold the power  at  a  certain  level.  Also  ALC  is  useful  in  avoiding  your  SSB  signal  from  being distorted  when  overdriven.  Depending  upon  the  manufacturer  of  the  transceiver,  the suitable ALC voltage differs. ICOM may need 0~-4V, and Yaesu may need 0~-5V range. Kenwood may need -6~-8V maximum. Check your transceiver manual.  8-1 Prepare an ALC control cable using RCA plug supplied in the package. Solder a single wire or (more preferably) a shielded single wire to the center pin of RCA plug and solder the shield braid to the outer side of the plug. Connect the control cable to the “ALC (or EXTERNAL ALC)” jack of the transceiver. External ALC input  is  sometimes  available  at  one  of  the  pins  of  the  “ACC”  socket  of  the transceiver as well.  8-2 At first, turn ALC ADJ full clockwise. Drive the amplifier in CW/RTTY mode to full  output  power.  Then  turn  the  ALC  ADJ  counter-clockwise.  Observe  the SWR/Power meter at the output, (or Pf of the multimeter). Stop turning the ALC ADJ at the point the power starts to decrease. Or if you wish to further reduce the  power,  keep  turning  ALC  ADJ  until  the  desired  level  is  achieved.  If  you further try to increase the drive power you will now see the output power become rather saturated, from these adjustments. (Maximum  ALC  voltage  produced  is  -10V  when  the  amplifier  output  power  is over 200W.) REAR PANEL ALC POT. SSSSTTTTBBBBYYYYAAAALLLLCCCCAAAALLLLCCCCAAAADDDDJJJJAAAACCCCMAX MINTTTToooo TTTTrrrraaaannnnsssscccceeeeiiiivvvveeeerrrr
13 9. Protection Circuits  There are five major protection functions in this amplifier. If the amplifier has shut down for some reason, before re-setting, correct the possible cause of the shut down. Turn off the POWER once and back on to reset.  9-1 O. DRIVE (Over Drive / Band Miss-set) When  the  drive  power  exceeds  the  100W  level,  the  amplifier will  shut  down  to STAND-BY mode (or receive) in order to protect the input side of the power FET’s. This protection might also activate if the band is set wrong. This usually occurs, when the amplifier band setting is lower than that of the transceiver.  9-2 O. HEAT (Over Heat) When the temperature of the aluminum heat sink in the power amplifier reaches 80 degrees C, the amplifier defaults to RECEIVE mode to protect the power FET’s.    9-3 O. VOLT (Over Voltage) If there is a sudden AC line voltage spike, the FET drain voltage may rise above acceptable levels, and O. VOLT protection may trip.  9-4 FUSE (Fuse Blown) If  either of  the  glass  fuses  (15A)  on  PC1662V fails,  “FUSE”  lamp  lights.  Under normal usage of the amplifier, this failure should rarely (if ever) occur. If it occurs, there is a possibility that the power  FET’s  have failed together. If the  amplifier cannot be reset, consult with the dealer or the service center.  9-5 PR (Reflected Power Protection) If reflected power from the antenna reaches approximately 80W, the PR protection may trip. If it does, one solution is to reduce the drive power from the transceiver. Or you may need to check that your antenna match (SWR) is still OK. If the match cannot be corrected and the antenna system isn’t faulty, use an antenna tuner.  As  noted  above,  the  amplifier  is  equipped  with  several  kinds  of  fast  acting  protection circuits  using  the  latest  in  analog  technology.  However,  if  the  amplifier  is  operated  in such a manner that multiple protections work repeatedly over a long period of time, the amplifier can be seriously damaged.
14 10. Explanation of Major Circuits  Four major circuit blocks are explained in their basic form and using signal flows. 10-1 Main DC Power Supply 10-2 Power Amp/ L.P.F. 10-3 RF Power Detector/ TX-RX Switching 10-4 Control Board   10-1 Main DC Power Supply The main DC power supply feeds the 42V DC power to the final PA stage. It is a state  of  art,  switching  power  supply  with  high  efficiency.  A  part  of  42V  line  is converted to 24V using a DC-DC converter and is supplied to the cooling fan.  10-2 Power Amp (PA PC1662V) / L.P.F. (PC1817) The RF  PA is the  heart of this  amplifier and is composed of four VRF150 MOS FET’s made by Microsemi of USA. The amplifier is a parallel push-pull, class AB amplifier.  The  gate  bias  supply  circuit  is  regulated  for  the  best  stability  and  is thermally compensated. The PA has a 6dB attenuator on the input for gain reduction and to enhance the stability  of  the  wide  band  power  PA.  The  heat  sink  has  two  different  thermal sensors to detect temperatures of 50 deg.C, and 80 deg.C, respectively. At 50 deg.C, the cooling fan shifts into high-speed mode. At 80 deg.C, the amplifier will lock the amplifier into RECEIVE mode to protect the power FET’s. In the L.P.F. (output low pass filter) circuit, there are seven band filters that are selected by the manual band switch. Each L.P.F. is used to reject harmonics so that the  amplifier  meets  international  telecommunication  equipment  standards, including FCC rule.  10-3 RF Power Detector / TX-RX Switch (PC1821) As  illustrated  in  the  block  diagram,  there  are  two  RF  power  detectors  on  this board. One detects the drive signal level from the radio and the other monitors the outgoing power and the reflected power from the load (antenna). The  TX-RX  switch  (Send-Receive  switching)  will  switch  the  flow  of  drive power/output  power  and  the  incoming  signal  from  the  antenna  with  two high-speed relays mounted at the input and output sides of the PA.
15 10-4  Control Board (PC1818) This is the heart of the control signal processing for the HL-550FX. It judges the operating  condition  of  the  amplifier,  as  well  as  issuing  the  commands  to  the peripheral circuits. Various analog signals are processed such as RF drive from the transceiver, RF power signals at various points, DC power supply information, etc. There are ope-amps, various three terminal voltage regulators, GAL logic device etc. Warning signals are processed by the logic IC for Over Heat, Over Voltage, Pr, Band Miss-set etc. Ope-amps produce the necessary DC signals to drive the Pf, Pr meters. Also there is a control circuit that issues the drive shut down command in case of the over drive, band miss-set and high antenna SWR conditions.
16 11. Trouble Shooting  Failure  Possible Cause  Solution AC mains not operating ① AC fuses blown ② AC cord not plugged in ③ Interlock switch lifting ④ Wrong tap used on power transformer primary ① Replace with new ones. ② Plug in securely.  ③ Screw bolts tightly on the top cover.  ④ Correct primary wiring. Can’t enter Transmit mode ① Remote control cable not connected ② Protection circuits ON ① Check the cable and connect properly.  ② Check the drive power, antenna SWR. Reset with AC POWER switch. O.Drive lights ① RF overdrive ② Band miss-set ① Decrease drive. ② Match the BAND correctly. PR lights  ① Reflected power high, Antenna SWR high ② Poor connection to coax cables ① Check/adjust antenna (Or decrease drive.).  ② Check the coax cable connectors. O. Volt lights  ① Drain voltage of power amp extremely high ① Check AC line stability. FUSE lights  ② Fuse blown  ③ Antenna SWR high ④ Short circuit ② Replace F202 and F203 (15A) on the PA board (PC1662V). ③ Adjust the antenna. ④ Contact the distributor, or service center. O.Heat lights  ① Internal Temperature above 80 deg.C Cool off until LED turns off. Check for air intake blockages. Also check air vent on top cover. TVI, FMI  ① Overdrive  ② RF leakage from coax cable, grounding wire, AC power cord etc. ① Decrease the drive. Check ALC setting. ② Insert common mode filters on antenna cable or AC line. Add clamp-on ferrite cores (TDK, Amidon, Palomar) on various cables.
17   12. Parts Layout  12-1 Top View (Detailed) 12-2 Top View & Side View 12-3 PA Unit (PC1662V) 12-4 LPF Unit (PC1817), Sub AC Unit (PC1819) 12-5 Frequency Detector Unit (PCS1733), RF Power Detector Unit (PC1821) 12-6 Control Unit (PC1818)   13. Schematic Diagrams  13-1 PC1662V PA (Power Amplifier) Unit 13-2 PC1821 RF Power Detector Unit 13-3 PC1817 LPF (Low Pass Filter) Unit 13-4 PCS1733 Frequency Detector Unit 13-5 PC1818 Control Unit 13-6 Overall Block Diagram

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