ANOTHER dead valvestate !

[Valvehead]

e / b /c

tr4 -35 / -34 / -35

tr7 +26 / +41 / +41

[Enzo]

Um...

How can you have +26 on the emitter of TR7, with +41 on the other two TR7 is an MPSA56. Looking at the flat front face, the legs are left to right E-B-C. I am made to think EITHER you are reading the legs in the wrong order, OR the transistor is in backwards. ANy possibility of that?

The fact you have about -35 on all three sides of TR4, and +23 or more on all the legs of TR7 tells me that the circuit through TR9 is either open or the transistor is not conducting. Oh wait, TR9 is missing?

[Valvehead]

they are on the board right--maybe i read them backwards...emitter and collector .

yes TR9 is out of the pcb right now

[Jazz P Bass]

TR9 & 10 are out of circuit.
You really should complete the path.
1K resistor on TR9 & 10 base to emitter connections should do it.

[Jazz P Bass]

The way that TR7 & TR4 are biased, they should barely be On.
Meaning the collector voltages of both should be very, very low.

[Valvehead]

ok--ill try installing the 1k res tonight and report back---thanks !

[Valvehead]

ok...

tr8 still in.....9 and 10 out . 1k res installed as said.

readings b / c /e

tr8 +26v / +41 / +40

tr9 holes +10 / +26 / +5

tr10 +6 / -41 / +40

[Jazz P Bass]

TR7 & TR 4 are most likely bad.

[Valvehead]

put the 2 chips in , replaced tr4 / tr7 .

powered on with the limiter in place = still has a short-no change

[Jazz P Bass]

So what changed?

Before the most recent parts replacement (TR7 & 4) you had the amp off of the limiter.
Correct?
And you had the 1K resistors installed (to prove out the voltages)
And you did not have a short.

Personally, I don't know why you reinstalled the output transistors, as of yet.
The last go round showed a very high voltage on the bases.
Not good.

What gets me is where is the current going.
There is not a load hooked up is there?

You have to get off the lamp limiter.