19-07-1998 Service notes on TR-7200A
Author: Trio-Kenwood Communication, inc.


Service bulletin no. 23 (31-10-1977)
RECEIVER

  1. No squelch: Check C84 47uf on X55-1110-11.
  2. Intermittant receive: Check for D14 touching to ground on X55-1110-11.
  3. Both Q17, Q18 audio transistors burned up: Send for bulletin before replacing.
  4. Poor receiver sensitivity: Check for proper output of Q10 10.245 MHz stage. If it is defective replace xtal.
  5. No receiver audio noise: Check L23 discriminator coil.
  6. No receiver: No C9 voltage at X55-1110-11.
  7. Receiver sensitivity poor: Check D2 MI301.

Transmitter
  1. Distortion on audio TX: Bad Q8 TA7061 IC.
  2. No TX HI: Check for shorting terminals at HI/Low switch.
  3. No TX: Check for proper T9 voltage at X56-1190-11.
  4. No TX: Collector voltage SB at X45-1080-00. Check Q9 2SA496Y.
  5. No TX: Check D1 MI301.