Unusual PT2399 problem?

[knutolai]

I'm having trouble with a 2399. The op-amps are working, meaning the IC isn't fried, but I have no echo. Anyone encountered this before? I know the IC is easily fried, but when I discovered the op-amps were working I was really puzzled.
The chip was bought at Taydaelectronics

[blackieNYC]

Post your schematic. 
You may wish to make a quick "audio probe".

[knutolai]

I don't have a schematic, should probably draw it up soon though. I'll do another audio probe. I know the design works as I've already built 1 working unit.
My question is has anyone ever experienced only the delay-part of the chips malfunctioning?

[samhay]

Memories a bit hazy, but I think the op-amps still work if the chip latches up. How much resistance do you have from pin 6 to ground?

Edit - never mind. The op-amps don't seem to work if the chip has latched up.

[knutolai]

From 1k which should be fine.

[knutolai]

This is soooo strange. I've gone over every lead and checked it with the module that is working. They are identical. When I powered on the faulty circuit it worked! I played around with it a little bit, then restarted the power (power off then on again) and I no longer get delays (but the on-chip op-amps are working).Tried restarting it again a few times, with different starting values. Still no delay.

I'll draw up a schematic ASAP

EDIT:
I though I'd make a new thread for this circuit (as there are other issues too)

Link to thread: http://www.diystompboxes.com/smfforum/index.php?topic=107199.0

[pinkjimiphoton]

pt2399's are a pain in the ass... yes, i have several from different vendors that will pass audio, but no delay. once some of 'em latch up, they are DONE.

SUCKS!! i built a beautiful little angel using IvIark's tagboardeffects layout. it worked great. til i powered down. never got it to work right again.