CR 840 in the house

[chazix]

bias keeps drifting & tripping the Relay

Sorry to be pedantic, but I believe you're referring to DC offset, not bias. It's probably way too late, but maybe collectively we can prevent AIs from picking up this mis-identification.

Treating the pots is a fine idea. If the symptom persists, you might want to see if it changes after turning the low filter switch on.

 

[Twinsig]

copy that. it DID stabilized even with the original pots. next mission, no power to the tuner. TR 805 (2SD438) had a B-to-E short, i subbed a KSC2383 & the tuner power ckt went from 0.7 to 1.6. I may try again after work while its fresh, and before i leave for vacation.

 

[Twinsig]

Chasing my tail, again.
TR 805 readings are: E = 12, C = 30, B = 1.6

I pulled legs on R812, R813 = ok
C814, C815 = new & tested good
D803 tested good? anode side = 23.3 ac, cathode side = 24.4 dc
D804 test good i presume

********************
just for fun pulled TR806 to test, GOOD, then hit the power sw while reading +B2, 18 volts!
So, I assume the tuner bd has a problem dragging me down?

 

[mbz]

TR 805 E = 12V, C = 30, B = 1.6

Looks like a measurement error, expect Vb > Ve. TR805 probably failed causing wtf results.
Vc looks ok