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Hey folks,

Well, I fired up the amp today...no heartbeat. Something's not right.

I've gone over the layout and doublechecked all the connections...everything seems ok...

Both channels seem to be dead. I'm getting a *very* *very* faint sound when plugged in (barely anything at all, when cranked)...but for the most part, it's just not putting out anything.

I've tested voltages up to the el84s and the PI, I believe...they all seem to be inline...I'm going to test the hwole amp later...

Regardless, can you guys offer any suggestions that might help me get in the right direction?

Thanks,
Frank

Assumining your voltages are OK.


If both channels are dead, then it's probably around the PI, unlikely it's the EL84 but possible.

Are all your tubes good? Replace the PI & try again.

Do you have heater voltage on all the correct pins (4 & 5 on the 12 AX7s)?
Touch the input pins of each stage with a little insulated screwdriver and see if you get a decent 'pop'. Work back from the EL84s. If one stage doesn't give a good 'pop', suspect it.

Check the resistor values around that stage or even the tube for the correct values. Could just be no gain. Maybe suspect the bypass cap on V1. Remove one end from the board.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Well, I spent the past hour tripple checking every connection....it's all good. Then I fipped over the amp to pull the tubes....and I noticed the problem right away...

The red lead (center tap for the primary) of the OT pulled from the OT.
That *has* to be the reason!!!

So I'm going to have to get this fixed before proceeding...


Blocked at every turn!

anyway, when I get this sorted out, I'll get back to you guys...

-F

I hope it's not too hard to fix. You will probably have to dig into the tranny to grab a lead to re-attach. Good luck at that! Fill it with epoxy after you've repaired it.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Hey guys,

s2 talked me through the repair on the tranny and I got the center tap on the OT primary reattached.

Just fired up the amp and all is well!!! The plate leads on v1 are reversed, so I have to plug into the normal inputs to get the TMB channel and vise versa...but this is a 2 second fix that I'll do in the next 10 minutes...

needless to say, this thing is going to get a workout tomorrow morning!

-Frank

Fantastic. It might be useful to know how you reparied it. It's going to happen to others. I suppose you did a photo essay on that, did you?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Actually, that I didnt....too bad...

I was more aprehensive over the OT going down, so it never occured to me to record it with a series of photos...

But I will definitely write up something about the repair...

Frank, it's already tomorrow morning ...

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps