90’s Univibe, power no signal

[Mr_bibbles]

I have a Univibe that does not produce signal, bypass or otherwise.

All of the LEDs light and toggle correctly. The power source is 18v.

People have documented failing voltage regulators in these, but I am getting 15v off of one lug.

Does anyone have a good idea as to where to start? Trace the signal? Test the regulator more thoroughly?

Thanks.

http://milas.spb.ru/~kmg/files/schem...ic%20(2-2).pdf

[The Dude]

Does anyone have a good idea as to where to start? Trace the signal?

If power supply checks good, that's where I'd start.

[Mick Bailey]

There are a number of voltages; A+, B+, C+ and VBias. Check them all. I've had these pedals in for repair where the 100R resistor in the A+ supply is open. If this is the case then you'll still get 15v output from the regulator.

[Mr_bibbles]

Thanks Dude!

I tried that, this board is really tough to trace.... over and under board traces, no designation numbers... didn’t make it far.

Mick, that’s awesome advice. I’m having trouble locating that 100r-

There’s only one brown/black/brown in the board and it’s no where near the dc in. Do you remember roughly where it would be??

[Mick Bailey]

It's a couple of years since I last had one for repair and I can't recall the specific location, It's straightforward to check if the supply is there though on the ICs it supplies - U3-U7 & U10.