Messages

what caps are you using in c3 and c33?  (2.2 UF np)

It is interesting that you have this result from 3 separate builds for the pedal. 

In addition to checking for continuity to the voltage pin(s) for IC5, check to see if the pin is shorted to ground. 

if it worked and stopped, I'd start with swapping out transistors if they are socketed.  same for ICs.  mostly because they are more prone to failure than the other parts, and because it is easier to try those things before you start troubleshooting the circuit in earnest.

what was the problem with your build that you found and fixed?

glad you got it working. 

Seems like you are losing the chorus because the delay chip stops getting the power it needs.    I would try swapping out the regulator, although if you see the same behavior after that try checking/changing c19 and c20.    Something that briefly works may be tied to a capacitor that is breaking down after being powered momentarily.

Don't worry that you do not yet have a working project.  You picked a very difficult build even for an experienced builder, and it would not be unusual for that person to have to find and fix problems to get it working. 

Your board is (probably) not bewitched, but it is a complex build that might have more than one issue in it that you will need patience to find and fix.  You already have corrected the big problem of trying to build the board with two different sets of memory chips where only one of the two sets is supposed to be used.   Any time you find and fix a problem you can see if the board works, and if it does not start over looking for the next problem.

Go back and measure all or your voltages again and see what you get because removing the extra set of memory chips may have changed some of those voltages.  Then check to make sure you have good ground connects on the board for the different parts of the circuit diagram that shows a connection to ground.    It may take a while to work through these issues, so don't worry if you set it down for a while and go build another project where you might learn a bit more that will help you get this one working.  It helps to realize that you probably have 99% of the board put together correctly and you just need to find a fix a few things to get it working.

If you think about it, it makes sense that if you see a discrepancy it is more likely that the build document was updated to work with an existing PCB, than it would be if a new version of a PCB was issued without updating the build document.    Odds are pretty good, though, that either part will work in the build even though someone decided a different part might work a bit better.

I don't recall, have you tried swapping out the transistors in the LFO?   The transistors are reportedly working under stress when the circuit is working correctly, so maybe one of them failed while getting the other parts of the power to the transistors sorted out.

Thanks for posting the two videos.   Pondering what to suggest.

It sounds like the socket for the IC may have a bad solder connection.  Try touching up all of the solder points for the socket, making sure you heat each pin enough to remelt the solder.  So long as every pin on your IC is in the socket and the IC is evenly inserted, it is likely seated OK.   For your SPDT switch you can try touching up those connections too.  If you have any visible holes around where the SPDT posts meet the board you might want to add a bit more solder to those points.

Does your bulb light up when the effect is on?   Or does it remain off? 

Setting your rate control at the slowest setting (fully counter-clockwise), the intensity control at mid-point, with the gain and offset trim pots set in the middle of their rotations, using your DMM, what voltage do you get at the bulb when the effect is plugged in?  Does the voltage change or is it constant?    If it changes, what is the range of the volts?  Does your reading change if you set the intensity control all the way clockwise?  If it changes, what readings are you getting then?   

Are you getting those volt ranges when testing at the bulb?   I would think that those diodes in the circuit would cap the volts at the bulb from going that high.  And are you using the bulb for the light and not an LED?  (I mistakenly referred to an LED in my earlier post)

I see the range of voltages you measured.  Now, if you put the trim pot for the flashing circuit minimum/middle/maximum and just measure the voltage at the bulb while the rate control is set to the slower part of its rotation, are you getting a fluctuating voltage for each setting?    (and my apologies if that is what is on your chart and I did not understand it).  Since it is an LED you only need something that falls below and then goes above the LED turn on point.   It may be that you have a fluctuating voltage going to the LED but it is either above or below that threshold.