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Modifications for the Kenwood T-599
Service Notes on T-599A/D

Author: Trio-Kenwood Communication, inc.
Service bulletin no. 7 (2-11-1977)
  1. No ALC - Drive 10 meters: Check for loose contact at oscillator wafer on coil pack.
  2. No TX any band: Check the T1 on generator board (X52-0009-00).
  3. No TX: Bad driver FET Q1 3SK22(GR) on X47-0004-00).
  4. No relay action when TX: Bad Q8 2SA562(Y). When replacing Q8 change resisto R16 to 4.7 ohm.
  5. Rubber belt slipping on drive and load: TKC has Chain Modification Kit.
  6. No drive when shock: Check for loose output terminals if final rotary switch (S10-1002-05).
  7. No output on any band: Check T2 GEN unit (X42-0009-00).
  8. No TX: Check final relay for burned contacts. (S51-4017-15).
  9. Bias current too high and blows fuse: Check for bad 6-7001A and shorted cathode resistors 10 ohm.
  10. Cannot neutralize: Make sure shield is properly installed on driver 12BY7.
  11. No output from generator unit (X52-0009-00): Bad Q4 TA7045.
  12. No 9 Volt out at AVR (X43-0010-00): Check Q1 2SA606(L).
  13. Low output power: If American 12BY7 is used in driver circuit, this can cause parasitic oscillation. Please use standard Kenwood replacement tubes.
  14. Blows fuse: Check for shorted electrolytic at power supply (X43-0011-00).
  15. AC hum on SSB transmission: Send for TKC bulletin.

 

Reducing 120Hz hum in T-599D

Author: Trio-Kenwood Communication, inc.

Service bulletin no. 17 (6-9-1977)

There haze been some cases of 120Hz hum in the T-599D. This may be reduced by removing L-1 (1mH) on the generator unit (X52-0009-00) and replacing it with a 47 ohm resistor. Shown below is the generator unit board with this change      


All mods found on this database are offered to me by other amateur radio hams or captured by Packet system. 
KB2LJJ  take no responsibility or liability for any damage done resulting from any modification.  
 I have been trying to help our ham radio with the radio modifications and have asked for any type of new radio mods.
 However, I haven't received too many.  If all of you contributed a little more,  I believe I would be able to help 
all the other ham's that are looking for these mods. I know it is possible to get more mods from all the Ham's because of
 the wide range that exist throughout the world.  By doing this we can  flourish and enjoy more of this hobby that 
we've taken part in for so many years. Furthermore, I ask you not to forget to send me any modifications that you might
 have through email.  I would really appreciate it.

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 73's
   John Ribeiro
             KB2LJJ