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 resistor R16 to 4.7 ohm.
   
   
5. Rubber belt sliping on drive and load: TKC has Chain Modification Kit.
   
   
6. No drive when shock: Check for loose output terminals af 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 electrlytics at power supply (X43-0011-00).
    
    
15. AC hum on SSB transmission: Send for TKC bulletin.

There hace 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.