Laney TT50H No Outout

[ca7922303]

Removed c24 jumper, c44 now(4.7k/4.7k ohms) presence 0-10.
The other red wire is connecting main board to midi board.

Was previously black but it became to short soldering and resoldering it so it was replaced.

[g1]

Was previously black but it became to short soldering and resoldering it so it was replaced.

Ok, it's a ground wire so if I see red connected to ground I get suspicious.

Can you post another picture just like the last one, but now with the C24 jumper removed.

edit: adding schematic of presence/damping/nfb circuit. Presence pot is 10K.

[ca7922303]

Ok, it's a ground wire so if I see red connected to ground I get suspicious.

Can you post another picture just like the last one, but now with the C24 jumper removed.

C24 jumper removed

[g1]

Measure resistance between connector pin in pic and the orange wire connected to R34.

[g1]

C24 jumper removed

Looking closer at it, the orange wire should not be touching R34. Make sure it is not. Then measure resistance from connector pin shown above, to the junction of R34 and R44.

[ca7922303]

Looking closer at it, the orange wire should not be touching R34. Make sure it is not. Then measure resistance from connector pin shown above, to the junction of R34 and R44.

Orange wire not touching R34, pin shown@D3 to junction of R34/R44(0.0 ohms)resistance.

[g1]

Orange wire not touching R34, pin shown@D3 to junction of R34/R44(0.0 ohms)resistance.

Check resistance from same pin of D3 to P15 pad (brown wire from output transformer).

[ca7922303]

Check resistance from same pin of D3 to P15 pad (brown wire from output transformer).

D3 pin 10(maybe) to P15 pad(4.7k ohms).

[g1]

It's pin9 of D3. Change position of damping switch and re-check.

[ca7922303]

It's pin9 of D3. Change position of damping switch and re-check.

Changed position of damping switch, pin 9 of D3 to P15(4.7k ohms).

[ca7922303]

It's pin9 of D3. Change position of damping switch and re-check.

Thought schematic was showing c24 going to D3 pin 10?

[g1]

Thought schematic was showing c24 going to D3 pin 10?

Yes. When we were testing the presence pot we used D3 pin 10. That all checked out so we are now checking the NFB (negative feedback) loop. The path goes from the 4ohm tap of the OT, to R45, out the other side of R45 on to R34/R44 junction.
So far we found that pin9 to R34/R44 junction is good, now we are checking from pin9 to the OT 4 ohm tap.

There was another thread started where you were trying to solve the feedback. Make sure any traces that were cut have been repaired.

Also recall now that the schematic has a small error and the 4 ohm wire goes to P14, not P15. So brown wire should be at P14, red wire at P15.

Disconnect the wire from P14 (labelled '4 ohm') lug. Measure resistance from P14 lug to D3 pin9.

[ca7922303]

Yes. When we were testing the presence pot we used D3 pin 10. That all checked out so we are now checking the NFB (negative feedback) loop. The path goes from the 4ohm tap of the OT, to R45, out the other side of R45 on to R34/R44 junction.
So far we found that pin9 to R34/R44 junction is good, now we are checking from pin9 to the OT 4 ohm tap.

There was another thread started where you were trying to solve the feedback. Make sure any traces that were cut have been repaired.

Also recall now that the schematic has a small error and the 4 ohm wire goes to P14, not P15. So brown wire should be at P14, red wire at P15.

Disconnect the wire from P14 (labelled '4 ohm') lug. Measure resistance from P14 lug to D3 pin9.

NOt trying to be any more of a pain than I've already been, but I really dread pulling all three(3) boards out again to get to P14. It seems like all the boards in and out causing alot of issues and then come the negative comments, so if there is some other way or maybe skip over that step if possible and come back to it if necessary? Just a thought.

[g1]

We can try. Post some close up pics of the impedance switch area, and to either side of it.

[ca7922303]

We can try. Post some close up pics of the impedance switch area, and to either side of it.