Phipli
Well-known member
I think I know what is wrong, but hope this helps anyone else that sees similar behaviour.
My dad's Mac classic clock doesn't advance when there is no battery installed, but does when there is a battery. Looking at the schematic, this probably means that the diode D2 is bad, or the traces through it. D2 looks like it is meant to prevent the battery back-feeding into the 5V rail (D1 stops the 5V trying to charge the clock battery). With it not working, the RTC is only ever powered from the battery. This isn't a major issue, but I'll look into fixing it.
In my case I suspect a bad connection because the diode itself tested good.
Here is the pertinent area of the Bromarc schematic. With a correction where they didn't know what VIA stood for. Ignore the red dashes, that's just me marking off traces I'd checked.
My dad's Mac classic clock doesn't advance when there is no battery installed, but does when there is a battery. Looking at the schematic, this probably means that the diode D2 is bad, or the traces through it. D2 looks like it is meant to prevent the battery back-feeding into the 5V rail (D1 stops the 5V trying to charge the clock battery). With it not working, the RTC is only ever powered from the battery. This isn't a major issue, but I'll look into fixing it.
In my case I suspect a bad connection because the diode itself tested good.
Here is the pertinent area of the Bromarc schematic. With a correction where they didn't know what VIA stood for. Ignore the red dashes, that's just me marking off traces I'd checked.