madbeanpedals::forum

Projects => General Questions => Topic started by: sdb guitars on February 22, 2013, 12:11:26 AM

Title: PT2399 oscillation question
Post by: sdb guitars on February 22, 2013, 12:11:26 AM
Can runaway oscillation (in, for example, a Sea Urchin) damage the PT2399 chip or other assorted parts in the circuit?  I assembled a Sea urchin last night, and it worked, though was a bit noisier than usual.  When playing around with allowing it to self-oscillate, suddenly it stopped echoing and started just passing signal.  Tried power reset, waited 5 minutes, etc., it wouldn't start working again.  I then tried no fewer than 4 other PT2399s before I was able to get one working again.

Also, is there a way to volume-limit the oscillation so that it doesn't kill the pedal/amp/listener?

Thanks,

Shawn.
Title: Re: PT2399 oscillation question
Post by: gtr2 on February 22, 2013, 01:34:09 AM
I doubt it's the oscillation, I've had pt2399's oscillating overnight by accident (amp off, delay on)  You most likely have a batch that locks up.  Try connecting pins 3 and 4 on the pt2399 and see if that works.  If so just solder a jumper there.
Title: Re: PT2399 oscillation question
Post by: sdb guitars on February 22, 2013, 09:40:26 PM
Oh, I've been soldering a jumper between pins 3 and 4 on all of my PT2399's just to cover that base... it's just weird that it would work for a while and then stop.  Drives me crazy.  At least it isn't boxed up yet.
Title: Re: PT2399 oscillation question
Post by: gtr2 on February 22, 2013, 09:43:28 PM
Maybe a faulty regulator?
Title: Re: PT2399 oscillation question
Post by: gtr2 on February 22, 2013, 09:44:05 PM
When its not working see what voltage you have on pin 1 of the pt2399.
Title: Re: PT2399 oscillation question
Post by: sdb guitars on February 23, 2013, 05:04:07 AM
An excellent suggestion, sir! I will keep my meter handy next time I plug in and test the board.