MK4 PCB problems- Now 2 boards won't work!

khabbi

New member
Joined
Feb 9, 2010
Messages
2,058
Reaction score
19
Location
Tampa, Florida
Well, here it goes, I hope someone can shed some light on what the problem may be....

I had a totally working MK4 PCB that had problems with the color red installed in a Z-cab, everything worked fine and the gameplay was great.. except the reds weren't there...

So I developed a liking for the game (damn it!, lol) and decided to purchase a 100% working PCB from a forum member, and upon getting it I installed it in my Z-cab.. It worked great for about 20 minutes, or until it got warmed up, then it started randomly resetting, I could sometimes get into gameplay and then it would reset within the first fight or two.. eventually getting to where it would reset to the point of just seeing the test screen, then it would loop into reset.. test screen, everything green, then reset when it was supposed to move on to the opening screen. Ugh. Ok, I thought I had a bad PCB, so I pulled it and put my old PCB back in the game.. and guess what.. did the same thing now with that PCB!!

So, thinking it may be a power supply issue, I changed out the power supply and checked everything out, and the power to the board looks good (both boards). I figured I had something else going on, so the machine was gone through and I can't find any other problems.

Well I just got a new MK4 cab with an MK2 board, and the MK2 board runs like a champ, and everything works great... so I plug my MK4 board in (the new one) and it starts up cold pretty good, but once warmed up it goes into a reset loop again.

Does anyone have any ideas what steps I should take next? Did this one board somehow create problems for my second board?? I know, wtf am I talking about, but hey, the started doing the same problem once I replaced my working board with the second "fully working" board. I don't know what else to think.

Any help or ideas would be great! Or should I find a place to send my PCB to for repair, and if so, where's a good, reputable place to send it?

Thanks in advance for any help....
 
I don't know anything huge in detail about the security chips for these, but a similar symptom would happen with Mortal Kombat 3. if you had MK3 originally, and simply replaced the roms for UMK3 and left the security chip alone, the game would run and everything, but it would randomly reset. the same would happen vice versa (retrograding UMK3 to MK3)

first area I'd check would be the security chip that it's seated in properly. (on the board that resets)

for the one missing red, I think it's a common failure area on these boards in the video section. that I guess check for broken traces. if it's something easy enough, I think some users on here with surface mount soldering experience could maybe repair it.

were both boards bought in an "untested, as-is only" condition? I made that mistake once with a Killer Instinct board... never again. I only go for equipment that's tested and working.
 
I don't know anything huge in detail about the security chips for these, but a similar symptom would happen with Mortal Kombat 3. if you had MK3 originally, and simply replaced the roms for UMK3 and left the security chip alone, the game would run and everything, but it would randomly reset. the same would happen vice versa (retrograding UMK3 to MK3)

first area I'd check would be the security chip that it's seated in properly. (on the board that resets)

for the one missing red, I think it's a common failure area on these boards in the video section. that I guess check for broken traces. if it's something easy enough, I think some users on here with surface mount soldering experience could maybe repair it.

were both boards bought in an "untested, as-is only" condition? I made that mistake once with a Killer Instinct board... never again. I only go for equipment that's tested and working.

Well, both boards starting doing the exact same reset loop after I installed the 2nd or "fully working" board. Very weird.

So how would I locate the security chip? Anyone know where it's at on the PCB?

One board was installed in a conversion cabinet (the one missing red) and the other was bought as tested/working, but since it worked until it got heated and the second board did the same thing when I put it back in, I thought it was a power issue. I now know that's not the case. I don't think the seller of the second board was trying to shaft me, it was just my bad luck of not having another machine to test the board in at that time. The seller offered me a full refund but I balked because I thought it was the power issue. ugh.

I must say this has been frustrating beyond belief, it seems like an impossibility to get my MK4 machine running properly and with no issues. At least I have my MK2 and UMK3 to keep me busy until then...

Still looking for any and all advice on how to fix this! And if anyone has a working MK4 board they want to sell, let me know (would prefer revision 3).
 
oh, well if they're both doing the reset thing (sorry, reading comprehension FTL) then I don't know what to tell you. trying them both in a different cab yields the same results?

the security chip thing is irrelevant then, but it's a smaller IC chip, usually has a label affixed to it saying what game it's for. or maybe it's silkscreened, I can't remember off-hand.

also, if you installed a new PSU, they ship with the +5 voltage adjustment set exactly at 5.00 volts usually. I encourage if you have a multimeter to at least check your voltage at the JAMMA harness. if you do this though be very careful as you are at high risk of shorting things, and the power section's a bad spot to do it at. :)

PM me if you need help on doing this.
 
Those boards are notorious for popping solder connections on the surface mount chips if the board is flexed at all. This can cause all kinds of odd problems.
 
there he is. :D

I thought that was a problem with these, Zenomorp had a dead MK4 board where the video section was toast for I believe the same reason, I think a discussion ensued on here about it.

chances are most everything I know about games on the technical side now was learned here. :)
 
I would adjust the +5 first. It might be that simple.

That's one of the best features of a Primal Rage board: It has two LEDs on it - one for +5HI and +5LO. When neither one is on it's dialed in just right. Are there other boards that have this feature on them?
 
Back
Top Bottom