I did see that ceramic cap but it wasn't in the schematic I was using. Sure enough that was the issue. I removed it and replaced with a 100nf ceramic cap and now the RTC draw is below what my meter can read. I also replaced C70 for good measure but that wasn't the original issue. I believe my RISCPC is now fully working. Thanks for the assistance.If it's a Rev3 motherboard there's more than one decoupling capacitor for the RTC - an electrolytic and a ceramic (probably 100nF).
Ceramics can fail partly-shorted, especially after battery leakage. It's near the RTC physically but doesn't look like it's wired to it.
1.5mA against a 1.2V battery is about an 800 Ohm load, which is right in the ballpark for that particular failure mode.
Statistics: Posted by Merrickd — Tue Sep 02, 2025 7:16 pm