Is it Possibly to Fry a 2399 Delay Chip (2006 BYOC Delay)

[tomer629]

I have an old BYOC Delay that I built in 2006. After a few years it stopped working. Couldn't fix it and it got packed away. I got back into pedal building this winter and dug out the old delay thinking I could fix it this time. Did the standard stuff, reflowed board, completely redid off board wiring. It still doesn't work.

One thing I noticed... Somehow the 2399 IC was in backwards. This pedal worked great for a few years so all I can think is that when I was troubleshooting it way back when, I must have taken the IC out and accidentally put it in backwards. Still doesnt work with IC put in correctly.  Is it possible to fry this chip by installing backwards? Or are they pretty much bulletproof?

Also keep in mind this pedal is 10 years old, so I wonder if the electrolytics are shot? How would I know? They look normal.


I have a multimeter but am still pretty inexperienced with how to use it in debugging a non-working pedal.

[Kipper4]

Welcome back.

It might be more useful to post the schematic you used and some voltages.
Take a lookie see the debugging below thread and report back.

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[vigilante397]

Is it possible to fry this chip by installing backwards? Or are they pretty much bulletproof?

It's been my experience that 2399's are among the more sensitive chips that we (or at least I) regularly work with. I live in a particularly dry area and I've friend them with ESD. I've put a 5V regulator in backwards and fried them with 9V. I've had them show up dead on arrival. I've never fried one by putting it in backwards, but I'm definitely willing to accept that as a possibility.

Question though: Does it pass any signal? On most builds even with a fried PT2399 they still pass dry signal if everything else is still working.

[tomer629]

Got it working. Turns out it was a bad input jack. Wasnt passing signal through at all even though the tip on the guitar cable and the tip connector on jack appeared to be touching. I bent it so its a tighter fit and it now works. I think the old problems I was having were fixed with reflowing and rewiring (and fixing IC orientation obviously) because it used to oscillate really bad and make screeching noises, and this was not the original issue that caused it to stop working years ago.

Anyway it sounds great now, except the middle knob (i think its repeats) doesnt do anything. Solder looks good. It doesnt scratch, crackle or anything when I turn it. Its as if its not even connected (maybe thats a hint )

I get exactly 1 repeat, so its still pretty useable for me.

[vigilante397]

I get exactly 1 repeat

That's my least favorite problem to debug on a delay. It means you're super close but something isn't quite working. There's one trace in particular on a Rebote 2.5 that I always seem to make too thin and if it comes disconnected it disconnects the repeats pot and gives one repeat. It's happened an embarrassing number of times

[duck_arse]

I get exactly 1 repeat, so .....

..... we still need to see circuit dia and build photos, etc, you know the drill.