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Troubleshooting bootleg Mortal Kombat

nassekova

nassekova

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I got this bootleg MK1 while ago. When I connect it to my HAS supergun, it pulls some current, but OSSC says NO SYNC ||

I have fully re-capped it and tried to look for any broken traces or legs, but don't see any. Today I measured those cables that go from JAMMA +5V to the board. They seem to be intact. Then I measured the voltage regulator and it took in about 12v and gave out 5,5v. Should it output 6v? It's TDA2003.

I heard some bootlegs might need a bit more juice to work, so tried to amp up my PSU untill HAS showed 5,50V, but still nothing.

One thing that came to my mind was that could it be the OSSC that can not handle my MK1? I remember that real boards had some kind of weird sync or something on them and they needed extra tools to work with OSSC? I have a BVM but it's not "plug and play" setup right now, so I don't wan't to drag this combo to it if there is no way its OSSC.

Any input appreciated how to continue from here! Usual suspects etc. Since it is a bootleg, I bet there is no schemantics laying around...

MK1.jpeg


HAS.jpeg
 
It seems that it is not! Here is a picture of the board and 14th from the right is not ground (marked red). 15th is (which should be "unused"?). Should I bridge the 15th from the right to the 14th and test it out? I'm pretty new with arcade boards and JAMMA so don't want to break my HAS supergun, but video ground is same as ordinary ground right :) ?

jamma.jpeg
 
If you connect your HAS to the board, is there continuity between pin 14 and Gnd?
 
I don't know about bootleg, but using a real Midway Y-Unit MK1 PCB it can be tricky because of the LCD/monitor accepting the very low sync rate.
Typically we use a iScan DVDO for its unlock 60.0Hz function, which corrects the issue but adds another... Lag (its about equal to Framemeister @ 16ms).

Make sure you are using the latest (0.85) OSSC firmware, and be sure its the OSSC that's the problem and not the display (ie take a picture of your OSSC's LCD screen).
If you see this (or a slight variation) the OSSC is working fine, its the LCD that is the issue...
wcqFYRq.jpg


Also notice how low that sync is @ 54.88Hz...
Most LCDs will accept from 58.0 to 61.0, but that is below the cutoff (Freesync gaming LCDs are recommended because they have far more flexible sync acceptance).
 
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My OSSC just says "NO SYNC" so it is not getting video signal from the HAS via SCART (at least one that it supports). I have the latest firmware (0.85) on it. I will check the Video Ground tomorrow with HAS connected to it.
 
Actually now when I looked that JAMMA pinout closely, I calculated those pins wrong. Missing KEY hole on these bootlegs really fucks you up :D And it did not help that pinout picture which I was using had key marked on the right side of the connector.. Need to print some kind of JAMMA cheat sheet like on this picture for later repairs...

But for the problem: Video Ground actually is connected! So that is not the problem...

tolleen.jpg
 
I have the same issue on a pair of Cadillacs & Dinosaurs bootlegs and a legit Mr Driller.
This is with a HAS v2 and I am not sure if it is an 'out of range' issue with the TV, an issue with the boards themselves or something else...
I have ordered a JNX 'Big Red' adapter so I can use Jamma in my MVS cabinet - hopefully the ability to adjust horizontal and vertical frequency will allow for some further tests...

I'm guessing that @jassin000 is also running his board via HAS -> OSSC, so the fact that you only see 'No Sync' can't be good... ;(
 
Yeah, I think I'll test it with my Sony BVM and if it shows no life at all it will get difficult for me to troubleshoot. I don't have any equipment to test any of the chips, so need to start looking on that stuff then. Or as always, it can be some broken trace somewhere hidden etc. I'll let you guys know what the Sony monitor says about it!
 
Does your HAS have a switch to enable/disable regenerated CSync?
Try that and see if your OSSC gives any signal info...
 
Oh guys you can't regenerate the sync, or even buffer it!
The OSSC don't like it if you do and won't lock it.

Nope the only way I've ever gotten it to work is setting sync to raw, and 75ohm then using a 8-pin mini din to SCART cable.
That will lock the OSSC, but then to dial in the image I must set v.active to 300 and v.center to 16~18 depending.

If you are passing into a iScan DVDO you must set the OSSC video output to 3x and use the DVDO's 60.0Hz unlock feature.
 
Well I tried it with my BVM now. Green line flashes fast and thats it. No picture, no sound. At first tried with HAS default settings, and then Csync "unprocessed" and there was no difference (sync level 75ohm). Back to drawing desk with it...
 
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