[Kenwood] Kenwood TS-570D(G)

[Dr. Gerald N. Johnson, electrical engineer]

Astrons do fail in that mode. Means all the pass transistors are burned
open, but at least one is shorted base to emitter so the driver
transistor is supplying the receiver load. Check the power supply with a
1/2 or 1 ohm resistor (which might be a length of iron picture hanging
wire). Then replace all the pass transistors, this time with the
thinnest smear of heat sink thermal compound under them to improve their
heat sinking. Be sure the individual emitter resistors have survived the
failure. Those emitter resistors would be more effective if larger
values, though that hurts the already abysmal power supply efficiency.

73, Jerry, K0CQ
-- 
Entire content copyright Dr. Gerald N. Johnson. Reproduction by
permission only.