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Twin Peaks Tremolo - No trem from Opto 1

Started by Timko, February 10, 2017, 04:30:21 PM

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Timko

I've had a lot of issues with this build, but I finally got the optos I built working.  However, I think with all of the soldering/unsoldering I did, there are some parts that I may have burned out a pad or somehow messed up a connection.  Right now, the bass only setting doesn't have any oscillation.  I did some probing around the board, and can see that the topmost leg of the LDR on opto 1 has a connection to the bottom pad of R7 (which makes sense according to the schematic).  It also connects to pin 13 of the TL74.  I probed Opto 2, and notice that both pins of that LDR connect to pin 13 of the TL074.

I assume that the other pin of the LDR should also connect to pin 13?  My knowledge of exactly how LDRs hook up is minimal, so I want to make sure I understand exactly what it's supposed to do before I start running wires to repair any damage I did.

Here's the build doc (with schematic) if you're unfamiliar.
http://www.davidrolo.com/wp-content/uploads/2014/11/Twin-Peaks-Tremolo-2.1-build-doc.pdf

Thanks!

drolo

Hi,
None of them should connect to pin 13 (maybe you are looking at TL074 the wrong way around though)
I attached some pictures highlighting the LDR connections but could you perhaps describe more precisely what the problem is?
Is it only occurring with the bass only mode?
Can you check in each mode, by turning the tone pot one side and the other if you have modulated signal, steady signal, no signal and list it here?

Timko

Thanks David!  Like I suspected, the connection between the 2 LDRs show in the 2nd picture was missing. I I added a wire between them and it's up and running!  I should have the etch for the enclosure done this weekend (the first one didn't turn out; the lines were too small). I'm really excited about this one  :).

drolo