Zero Point SDX Issue

[Droogie]

Hi Guys,
I'm rehousing my "working" (at least it used to work) ZPSDX and I'm perplexed by the fact that when I test the circuit on my tester it works great, but when I put the board in the box, the delay stops working immediately. I still get signal, and the modulation light flashes. When I remove it from the box, the delay still doesn't work. If I wait 24 hours and test it, it works. I'm confused!

Anybody have any ideas?

Thanks!

[midwayfair]

Sounds like some sort of short causing the chip to latch. When you wait, the chip resets and is no longer latched. Look carefully around the left side of the PT chips for anything that might short against it when you put it in the box (back of a pot perhaps?).

[Droogie]

Okay, I'll start looking there. The infamous chip latching.

Thanks!

[Droogie]

That totally solved it! Pot grounding against 2399—fixed with cardboard. Thanks for the tip!

[selfdestroyer]

That totally solved it! Pot grounding against 2399—fixed with cardboard. Thanks for the tip!

I found this happen to a few builds I have done in the past. It good to have some of these laying around:
http://smallbear-electronics.mybigcommerce.com/dust-cover-for-16mm-alpha-pots/

Cody