SOLVED Cepheid chorus no effect strange voltage in tl022

[Locrian99]

Kinda funny I commented on a trouble shooting thread for this build last night out mine together and I’m having an issue.

I get signal no effect. I played around with the trim pot a ton, nothing. I think I have a lead on the problem but not sure what would be causing it.

I’m getting 7v at pin 8 of the tl022. I thought maybe I had a bad 9v1 so I replaced that same. Used one of these in my Caesar buikd months ago and it works fine there. Traced back through the power section. Positive lead of the 220u cap where it meets with +9V also 7v. One side of the 33 ohm before that also 7v other side is 8.81. Mine 4558 is getting the 8.81, though the other pins are all showing half of the 7v supply.

Any tips on what would be causing this? I thought I had some 1w 9v1’s on hand to try but can’t seem to find them to try a different part for the diode, or am I barking up the wrong tree thinking it’s the diode.

Lfo is working I shoved a led in the rate area just to check. I pulled a known to be working pair of 3207/3102 from another pedal just to check that as well. I’m thinking it’s connected to the 7v power but not sure what would cause that.


Thanks

 

[Locrian99]

Omg I just saw it looking at the pic I have a backwards electo!

 

[Locrian99]

Well solved. Unfortunately I think I fried 2 sets of chips. Thankfully I have some spares.

 

[Locrian99]

Still doesn’t exactly make sense to me. On one side of the 33r I was getting the 7v on the other I was getting 8.89. But that side getting the 8.89 is connected to where I had the part backwards the 47u between vref and ground by the trimmer. I would think it would affect both side of that 33r. Which would’ve made it easier to figure out other than opening my eyes and looking at the board obviously . Anyways, pedal working time to throw it in the pile of boards waiting for me to drill some enclosures. Aka board purgatory.