Laney TT50H No Outout

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

No output except low somewhat distorted thru return jack. Replaced all power/preamp tubes with known good tubes. Contact cleaner on cable in efx loop several times/overnight, jumped efx loop, no change. Any ideas greatly appreciated.

[Helmholtz Old Timer Find all posts View Profile Close Helmholtz]

No output except low somewhat distorted thru return jack. Replaced all power/preamp tubes with known good tubes. Contact cleaner on cable in efx loop several times/overnight, jumped efx loop, no change. Any ideas greatly appreciated.

Schematic?

[vintagekiki Uneducated Find all posts View Profile Close vintagekiki]

https://elektrotanya.com/laney_tt50h_schematic.pdf/download.html

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Have the schematic, thanks. Have a multimeter and have done some basic testing and soldering of resistors and caps. Am aware of how to drain voltage before working on amps.

[Helmholtz Old Timer Find all posts View Profile Close Helmholtz]

Have the schematic, thanks.

Please post it here for reference, so we all know what we're talking about.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

OK

[Helmholtz Old Timer Find all posts View Profile Close Helmholtz]

Can't find a power amp schematic, only layout.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

I got this link from vintagekiki on this site, thought it was complete. Didn't look it over well enough I guess. Will see if I can find it elsewhere?

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Drawing#9357_3 & 9357_4 are main power board drawings, but I cant find anything else online. I guess I'll have to try to email Laney?

[Jon Snell Senior Member Find all posts View Profile Close Jon Snell]

Post 3 contains the link to the service manual. Everything except a picture is included, even those connectors that is the main issue with most problems.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Just ran line out and record out to another amps input and got a good clean signal. None of the preamp controls on channels 1,2,3 work, but volume 1 and volume 2 work, amp mute works, and fx mix is scratchy and tries to cut volume off at "0" but intermittent scratchy signal still comes thru at "0". Also, there is a high pitched whistle if volume is turned up past "8" on either amp. 2nd amp does not do this when TT50H is not plugged into it.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Just ran line out and record out to another amps input and got a good clean signal. None of the preamp controls on channels 1,2,3 work, but volume 1 and volume 2 work, amp mute works, and fx mix is scratchy and tries to cut volume off at "0" but intermittent scratchy signal still comes thru at "0". Also, there is a high pitched whistle if volume is turned up past "8" on either amp. 2nd amp does not do this when TT50H is not plugged into it.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Just ran line out and record out to another amps input and got a good clean signal. None of the preamp controls on channels 1,2,3 work, but volume 1 and volume 2 work, amp mute works, and fx mix is scratchy and tries to cut volume off at "0" but intermittent scratchy signal still comes thru at "0". Also, there is a high pitched whistle if volume is turned up past "8" on either amp. 2nd amp does not do this when TT50H is not plugged into it.

[ca7922303 Senior Member Find all posts View Profile Close ca7922303]

Wondering if a bad efx mix pot could cause preamp to not function?

[g1 Don't forget the joker Find all posts View Profile Close g1]

Drawing#9357_3 & 9357_4 are main power board drawings, but I cant find anything else online. I guess I'll have to try to email Laney?

Yes, I would contact them and ask if there is a schematic showing the power amp.