-----Original Message----- From: Neil Cherry via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> Subject: Re: [vcf-midatlantic] Repair Workshop reminder 1/14 & 1/15, 2023

Reset sees a low (/RST) every 3s. So there is a watchdog timer setup. I traced it back to a MC14584B (yea!) which is a hex schmidt trigger (what? ;-) ). So I have to do some more tracing but the MC14584B is socketed so I'll build a manual reset circuit and figure out what is going on later.

Ahh, the Schmidt trigger.  Pairs of those gates are good for fixing marginal amplitude issues and/or "squarifying" a less-than-square waveform.  If the RST signal looks well-formed, then the problem is probably upstream of the Schmidt trigger. -Jonathan