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I built this a couple of years ago and was working perfectly until a couple of days ago. I get a slight gain boost but no vibrato sound. I built this with the Speed Shift mod and the 45/90 mod. Tried turning the trim pot with no luck. I did record the values on the transistors and ICs and will recheck to see if anything is off. Any suggestions?
Are the transistors socketed. Make sure they haven’t come loose (wiggle test while on). Was there a power surge to the pedal?
Sockets are soldered to the board and not loose. No power surge to the pedal either. Checked all of the voltages and they read the same as when it was working properly.
Hi, he meant to make sure the transistors in the sockets are not loose.
My best advise is to re-flow the entire board and all off-board wiring since that is the most likely cause.
Standard Operating Procedure for such an event.
Thanks Barry. I did socket the 3 ICs when I first built it back in May 2017. I replaced the TL074 IC2 with no luck. I refloated everything and it is still not working. Don’t have any spare TL071 or TL061s to see if that it the problem. Even though the voltages on the 4 trannies seems correct, is it possible one or more of these could have failed?
What is the best way to test the trannies? I have a multimeter that tests for Hfe values.
Just realized that these are FETs.
Looks like I am going to have to remove the trannies and install sockets. I have 7 2N5457 which are supposed to be similar to the 2N5952. Have no way to match them so I will try various combinations to see what I get. I also found a TL071 which I will swap out.
Looks like it was one of the 2N5952s. Put 4 2N5457s (had to reverse the orientation since the pinouts are different) and got a fairly decent vibe sound. Will have to order another matched set of the 2N5457s when they are back in stock.
Hi,
seems that I have the same issue of Dan.
I just populated the board, double checked all the components but when I turn it on I get only a volume boost and no vibrato at all.
It’s my first build for this specific type of effect and I don’t know what can be the standard voltage values.
Can anyone help me?
@ Gio – You should start your own thread.
Just because it is not working does not mean it is the same problem.
Dan sorted his out by getting a proper set of matched transistors.
We need more information like where did you get your transistors, which ones are you using and what are the voltages.
Sorry, I’ll start a new thread. ✌
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