Did the VMU just damage my Dreamcast?

[Mumford67]

Moving this from another thread at the request of a user on the forum.

Pulled my Dreamcast out of storage this weekend and noticed the VMU batteries had died. Replaced them with new CR2032s this morning.

I booted up the system with the VMU outside of the controller and got the date/time set screen. I inserted the VMU into the controller and then both the screen and VMU pulsed twice. Picture disappeared from the screen, red light died on the console and the Dreamcast became non-responsive.

Pushing the power button now has no effect unless I remove the plug from the back on the console first. If I remove and reinsert the power cord, the fan will come on but the red light faintly flickers, the drive doesn't spin and there's no signal being sent to the monitor. Anyone ever experienced anything like this before? Is the system salvageable? Or should I consider it dead and start searching eBay for a replacement? <sigh>

FWIW, it's been suggested that I check the pins on the power board, which I'll do tonight. I've done that previously for random rebooting issues so I'm comfortable getting inside the unit. This just seems significantly different than that issue.

Best,
Mumford67

[Anthony817]

Well, it isn't recommended to plug in controllers while the system is on as it could blow a fuse on the controller board. But I never heard of a VMU frying a system. Sounds like the batteries might have blown the PSU maybe? Not really sure how it would happen with the proper batteries though.

[Mumford67]

Controller was already plugged in when I booted it. Was just the VMU that was added while it was on.

[Farmhouse]

Just a guess, but I think the Dreamcast, after sitting for so long, some of the circuits probably oxidized. It powered on enough to show signs of life, but when the VMU was added, the Dreamcast probably accessed power though a resistor which probably fired when accessed.
If you have the experience, I'd open the Dreamcast up and look for signs of fried components.

Again, just a guess.

[Anthony817]

Controller was already plugged in when I booted it. Was just the VMU that was added while it was on.

Yeah and I clearly said I have heard of a resistor frying on the controller boards ONLY from plugging in a controller. NEVER the VMU's. Hence why I said that you plugging the VMU in lead me to think something similar might have happened unlikely as it might sound. And like the person above me said, letting it sit for so long could very well have let the internals become oxidized messing something up.

If you know your way with building/working on PC's you could also run the machine from a PC PSU to see if it would even power up without the PSU. Also there should be a fuse on the original DC PSU you could check to see if it was blown.



And PLEASE I can't stress this enough, be careful when messing with something like a PSU. If you attempt this, please make sure you ground yourself first.

[Mumford67]

Quick update: System is up and running. Opened it up and a quick examination showed no physical signs of damage to the CPU circuit board. Fuses and capacitors all looked healthy. So, before putting the CPU back in place, I took a chance and adjusted the pins. Put it back on and voila. It boots up and is running fine.

One interesting thing I did find, though. After rechecking the VMU, it appears I shouldn't trust the packagers at Duracell. The pack of CR2032s I bought actually contained CR2025 batteries instead. My dumb fault for not checking the engravings on the batteries. That is likely why it pulsed...slightly lower amperage and the batteries not making the right connections in the VMU. Not sure if that actually did anything to the board or if it was just coincidence, but I'm just thankful to have my DC up and running and thanking my lucky stars the system didn't potentially sustain more damage.

And a lesson learned. Always err on the side of caution and check the markings on the batteries themselves.

[Anthony817]

Awesome to hear that! Hopefully you enjoy all the latest homebrew ports like Cave Story and Volgar the Viking, which was released last year and is the full game same as on Xbox and PC.