Dreaded SVT3 Output Mistake....

[Enzo]

I mention C6,7 only because they block DC, and that means the tube didn't affect the DC problems of the outputs.

Q5,6 are limiters. If the current through R32 rises too high, the voltage dropped across it rises enough to turn on Q5. That in turn pulls down the gate drive with the help of D28.

You may have +65 on R22, but that doesn't mean it is getting to the output transistors or R10.

[Mr_bibbles]

Ok... So the only way that +65 could get to r10 is through q3 though, right? +65 is definitely NOT hitting r10, and since q3 had been replaced with a brand new 2n5415, the + voltage is being dissipated to ground somewhere WITHIN the output block???? What could possibly cause that??? All resistors seem to be in spec...

Also, I've removed q5/q6 for testing purposes.

Other things I've checked in the OP section:
R10 3.1k
R11 14k in circuit, 22k (schem value) out of circuit
R16/R17 - 15k each
R24/R26 2.7k Each
d9 / d8 Both .515 / .935 in circuit
D28/d29 Both .525/OL in circuit
R25/R27 327 Ohms / 315 Ohms (r27 Originally went up in flames.)
R13- 2.11k
R15 - 4.7
All Flameproofs measure between .4 and .5 ohms
IC1 has +16 on pin 4 and -16 on pin 11

[Enzo]

I mis-spoke, R10 does not connect to the +65, it gets its voltage through Q3, yes. But we need to verify we have +65 at the output transistors.

The voltage on the base of Q3 turns it on bringing some of that +100 down to R10, so what is on the collector of Q3?

You replaced some bad parts, but remember, not all problems are bad parts. If the copper trace between Q3 and R10 is cracked, the circuit won't work, even if the parts are good.

[Mr_bibbles]

Measuring q3 with Lamp Limiter:

Measuring the collector from the leg of R14, I get 80v

Measuring Base at D2, 77v

Measuring Emitter at R16, drops down to -44 volts

I will check all the traces underneath the board, q3's connections are good though.. Is there any other part of this circuit that would hamper the + coming in? Possibly q2 and the bias circuit? Or is there anywhere where a connection to ground would filter only the positive out? IC1?

[Mr_bibbles]

Also follow up question, can I safely disconnect the emitter of Q3 and measure the output? This would theoretically eliminate q3 as the problem, yes?

[Mr_bibbles]

Sorry to keep bumping this but.... Replaced Tl074, that's the offset 'corrector'? No change.

So instead of asking for magic answers, can anyone tell me if these troubleshooting plans are effective?

1. Can I remove all the Transistors on the + rail side to see if one of them was defective when replaced? Or will this fry the O.P. entirely due to imbalance?

2. Can I lift the emitter leg of q3 to measure the voltage on it? Would this damage the transistor, or instead let me measure the isolated voltage before it hit the OP trannys?