My Easy UMK3 Arcade Board Fix

Patrick McCarron

TRMK Admin, Co-founder
Staff member
I had bought a UMK3 JAMMA board a few months ago off eBay that was said it wouldn't power up. Due to some problems with my arcade cabinet I never got around to troubleshooting it.

So today I replaced my arcade monitor with another newer brighter one (long overdue) and then decided to fix my cabinet problem (another issue due to my multi-game setup needing too much power).

So I finally pulled out the "broken" UMK3 board, to find it was in fact not working at all. No PCB lights, no sound, no video. I was puzzled as the board looked flawless except it was missing a battery. I figured it would still start up without a battery. I reset a few ROMs, still nothing. So I finally decide to dig up my arcade board battery stash and put one in the board. I flip on the switch and...

BOOM I see lights and the board chimes. There was an audio ROM checksum error, but it worked perfect with no issues.

So moral of the story is, make sure your arcade boards have a battery in place. Doesn't have to be good, just needs a battery in the hole.
 
Haha! That's awesome. How much did you get the board for? Compared to one that was indeed working?
 
Haha! That's awesome. How much did you get the board for? Compared to one that was indeed working?

The prices on MK3/UMK3 boards are all over the map these days. I paid less by around $50 maybe because it was said to be broken.
 
Two questions:

1. I thought MK3 and UMK3 were different boards. I guess the UMK3 info was just an extra rom on the regular board?

2. I saw the pic you posted on Twitter of your old arcade CRT. Holy crap, did you just leave it running in attract mode for the last 10 years? Looked like you had the entire intro burnt in that poor SOB, lol.
 
Two questions:

1. I thought MK3 and UMK3 were different boards. I guess the UMK3 info was just an extra rom on the regular board?

No they have the same board, but they have different chips on the boards.

2. I saw the pic you posted on Twitter of your old arcade CRT. Holy crap, did you just leave it running in attract mode for the last 10 years? Looked like you had the entire intro burnt in that poor SOB, lol.

No I didn't own this machine until maybe 2006/2007? I bought it for $350 and it had an already burnt in monitor, but the rest of the cabinet was in decent (non mint) shape and had UMK3. I had MK2 and MK1 boards already that I ran via my TV. So this cabinet was a great fit for what I wanted.

Now my new monitor cost me around $450 but the price on old CRTs are increasing and this monitor will also do higher resolutions (I actually want to be able to run The Grid and MAME on it for instance).

Now that I almost bought what I needed to turn this extra UMK3 board into a MK3 board, I found I already have a MK3 board. I got too many arcade parts clearly.

So anyone need a UMK3 board? ;)
 
Requiring the CMOS battery for board start up is not necessarily true. If the battery has been removed for a long enough period that the CMOS chip dumps ALL it's info, then yes, the board will be dead. If the battery is removed temporarily and the CMOS chip has plenty of juice stored up, then the board will work fine without a battery. You'll just have a CMOS error telling you that your factory settings have been restored. That's been my experience anyway. I base this on the fact that I have had MANY boards work fine without a battery, but I get the CMOS factory settings error.
 
Requiring the CMOS battery for board start up is not necessarily true. If the battery has been removed for a long enough period that the CMOS chip dumps ALL it's info, then yes, the board will be dead. If the battery is removed temporarily and the CMOS chip has plenty of juice stored up, then the board will work fine without a battery. You'll just have a CMOS error telling you that your factory settings have been restored. That's been my experience anyway. I base this on the fact that I have had MANY boards work fine without a battery, but I get the CMOS factory settings error.

The long duration without a battery is must of what caused the board not to even power on. Always a good thing to try if a board is being problematic.
 
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