Thank you for all?the helpful comments.
I have removed, cleaned, and reseated all the socketed?IC's a few times with the same results. I also see no visible breaks in the PCB?traces.?
Thanks for the offer to send me the?OS?files.?Unfortunately, I?have no IC programmer and cannot burn new chips. ?I'll check the traces around the ACIA chips as suggested.
On Tuesday, February 9, 2021, 2:06 AM, Vladimir <shtirlitzz11@...> wrote:
Hello Joey. Could you do the dump of the new OS chips for comparing it. Or I could make the dumps of two OS chips and send you binnary) surely if you have the programer. UART and timer signals come from HD63 ACIA chips, did you check traces around those?
