What the heck is happening with this TC 2290 PSU???

[Sammas]

I have a TC 2290 on the bench... and it is a bit of a head scratcher. Symptoms = No sign of life. No lights. Nothing.

The PSU is nothing like I've seen before (usually just run of the mill linear psu stuff). Attached at the bottom are the schematics. I've never seen TIP31 & TIP32's before... what the heck are they? They are component number Q703 & Q705 on the schematic

And strangely enough... IC85 & IC86 are 7905 & 7805 regulators? For +/- 15v rails?

IC63 and IC84 are both LM324's.

The current state of the unit is, no lights at all. Regulators, Bridge rectifier and TIP31/32 are all brand spankers.

I'm getting an astronomical 22ish volts on the input of the 5v regulators. When I measure the voltage coming out of the transformer, I get 19ish volts AC between the primary and center tap (brown wire to black wire).

Any words of wisdom? I've never seen this unit functional. It could be dead as a doornail.

 

[owel]

They're dual tracking regulators. As you adjust V+, the V- follows suit.

Have you replaced the LM324s?

TIP31/32 are medium power transistors.

 

[Sammas]

Hey Owel, thanks for the reply!

Nope, I haven't replaced the LM324's yet. I'll give it a crack tomorrow.

 

[Sammas]

that did the trick!

Thanks Owel, you are the man.

This is officially the best $100 effect unit I have ever purchased!  ;D

 

[okgb]

I bought one in the 80's for live gtr  [ it switched amp channels
as well as effects ] Always loved it , great deal
I'd buy another for that , have fun & enjoy !

 

[owel]

Cool! 

No problem.

 

[mushy]

$100???  That kills me.  One of my favorites.  There's really nothing else out there like it.

 

[leadpoisoning]

hmm - i was having the same symptoms as the OP mentioned - took the advice on the LM324s as their output seemed dead and replaced them but still getting 26v or so into the LM324s ... you would think the problem is UPSTREAM of this i guess ...