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Hi All,

Just an update, replaced the 220 uf Electro CAP, still getting some white noise in the output, but maybe be due to background interference. Will box it up and see if it goes away.

i think the main culprit was my 9v power plug power supply. Running on an isolated 9V supply, the voltages on IC2 is staying constant and circuit is working well. Also replaced a few Electro caps along the way in my troubleshooting so not sure if they also contributed to the fix.

One thing i can say is the quality of the PCB is really good, multiple desoldering and soldering of the same components in some cases, pulling out components, the PCB solder pads and tracks have held up really well.

Thanks again for all the support

I've had some success running the pedal with an isolated power supply, getting a modulated output and it's been running on a loop for a few hours now. However there is a fair bit of white noise coming through as well.

I will replace the 220uf electro capacitor (I think for power filtering, I used an old one I pull out of another test circuit), with a new one that's coming in this week, hopefully gets rid of the white noise. I have already replaced the two 100uf caps on either side of the 78L15.

That's the type i am also using  . I just powered up the pedal just then and it's working perfectly. Disconnected power  and reconnected, working as expected, voltages on IC2 all check out as expected values . But if i keep it running for some time then the problems start. I will next power it with the isolated power supply from my pedal board, see if it makes a difference. but will also replace all the remaining electro caps from tayda with panasonic ones and hope by some luck it fixes it .

Hi Mate,

non of them are below 25V. But what I am planing to do is replace all the 22uf caps with Panasonic caps and also replace the 220uf cap as well. Should get them by Monday. This replaces all the electro caps from Tayda.

Keeping throwing forward any ideas, all appreciated and will be tested [emoji51]

Hi Scruffie

I've been trying to troubleshoot further, checking for an shorts or bridges and at the latest check of the voltages on IC2, I see The voltage on pin 5 and pin6 of IC2 is now at 1.2 V and pin 7 still on 14 volts. All the other pins on IC2 are as per the expected voltages. I've reflowed all the solder joints as well. Audio probing the signal path it does work up until the output of pin 11 and 10 of IC2.

Really scratch my head with this one [emoji848]

Hi Scruffie

I removed IC1 and IC6, and upon startup voltage on pin7 of IC2 was sitting at 7V, and after a couple of minutes it's now sitting at 14.15V, and remaining at this voltage.

No good, after a few hours Pin 7 is now sitting on 14V and sometimes drops to 7V and then back up to 14V. I've got some 22uf electro caps on the way, going to replace all of the caps so there will be no Tayda sources electro caps on the board. Will check in again in a day or so [emoji28]

Here's the update [emoji3]. I replaced IC2 socket, replaced c4, c6, c7 with Panasonic caps and evening put in a new ne571, same issue, wasn't working. Replaced C27 thinking it's linked to IC2 might help, didn't solve the problem. I put back in original v571.

Was about to throw in the towel. But Scruffies comment on Tayda caps kept ringing in my mind, so on a whim decided to replace C54 and C63, the two 100uf caps, with Panasonic caps. No logic behind it.  And circuit started to work as expected and it's been running now for 3 hours the voltage on pin 7 has remained stable at 7V and getting a modulated output.

Will keep it going for a few more hours and see if any issues come up. It's only been running in the flanger mode.

Was trying to read up to see how the caps for the voltage regulator could have an effect on the NE571, would be interesting to know.

So should I throw out all my tayda electro caps [emoji28][emoji51]? Never had an issue for my other builds until this one....

I've ordered some Panasonic electro capacitors and will replace all the electro caps connected to IC2. I'm also going to replace the IC socket for IC2 just to rule it out. Also got a new NE571 on the way. Although this is frustrating, I'm learning a lot and looking at this as a challenge to get this working. Will report back on how I go in a few days, thanks again for the support Scruffie and Jimilee

I've replaced both caps and pin7 voltage is really intermittent, sometimes it goes to 6.2v and sometimes it drops to 2V, and sometimes it's just fluctuating Between 2 to 4 V really weird. I've left it running and will see in the morning again. Also ordered two more N571 just in case....😕.

I just a minute ago replaced C6, same issue And will try replacing c4 as well and see how it goes. And yes some of the caps are from tayda. I see how I go and maybe get better caps if problem still persists. Hey man thanks a lot for your advice and support, I appreciate it.

Coming back to the same situation, it runs ok for a while, all voltages check out but gradually pin 7 on IC2 starts to drop to 2V and then no output, no changes made just running it On flange mode through a looper...

I replaced c29, c7, c12,r5 and r6 out of frustration and seems to have fixed the issues and flanging again, pin 7 of IC2 is sitting around 6.8V.  I'm leaving it run for a while to see how it fares [emoji3]. I had some weird readings earlier where pin 7 shot up to 14V. I cleaned up the solder side with a toothbrush and alcohol and Seemed to have stabilised now.

Hmmm.... seem to be back in the same position, where voltage on Pin 7 drops down to 2V. When I reflow the joints or clean up the solder joints with some alcohol, it starts to work, I get effected output and the voltage on PIN 7 sits around 6.8V, but I notice that as I leave it running the voltage on Pin 7 gradually starts to fall and once it gets down to 2V, just get a lot of static. Still trying to figure this out...? Hmm strange one. Could it be a defective Component around the pin7 region?

Thanks so much for your Patience, help and support.