Found a weird fix for a Dell Optiplex that kept blue-screening on boot

I had this old Optiplex 3020 from a client in Lansing that would crash maybe 3 minutes after startup every time. I tried replacing RAM, swapped the hard drive, even tested the power supply. Finally I noticed the CMOS battery was reading 2.4 volts instead of 3.0 - put in a fresh CR2032 and the thing hasn't crashed in 2 weeks. Has anyone else seen a dying CMOS battery cause intermittent blue screens like that?

2 comments

2 Comments

robertgreen1mo ago

Wait, wait. You're telling me a dying CMOS battery actually caused blue screens and not just date resets? That is wild. I have to admit I have never seen that in 15 years of fixing these things. I always assumed the CMOS battery only held the clock, but you are saying a low voltage like that made the whole board unstable? Did you check if the battery was leaking any gunk onto the board?

sagep191mo ago

Used to think the same way honestly. Had a similar Optiplex 7010 that would randomly freeze in Windows 7, maybe once an hour. Spent two days swapping parts before I got annoyed and just changed the battery out of spite. Never froze again after that. Still don't fully understand the electronics behind it but I have seen it happen on maybe 4 or 5 older Dells since then. Usually a system that works okay for a bit then just drops dead. That 2.4 volt reading is a good heads up, I look for that now.