Mortal Kombat 2 pcb all kind of problems

chinitosoccer · Mar 4, 2015

I have this Mortal Kombat II pcb, 3.1 revision with 8mbit mask rom chips (no extra rom board) which is giving me all kinds of troubles:

First of all, I can't get the game to boot at the first try, sometimes it gives me a ram error, sometimes a few of the mask check as bad, after a few tries turning the power switch on and off the game boots, the test menu shows all chips as good and the game starts just fine, but the sound plays in "Chip & Dale" mode :keke:

, it sounds like when you overclock the sound cpu in mame, the music plays faster and the voice samples..well... take a look:

ReplicaX · Mar 4, 2015

Check your -5v on load as far as the sound.

RAM errors is usually corrupt CMOS settings or the batt is almost dead. Try tossing coin settings to DIP instead of CMOS. Pull the battery as well and test it.

chinitosoccer · Mar 4, 2015

I'm running the board without battery, and I have tried the pcb on 3 different cabinets and on my supergun as well, can't be an issue with the -5v, isn't it?

Tacitus · Mar 4, 2015

chinitosoccer said:
I'm running the board without battery, and I have tried the pcb on 3 different cabinets and on my supergun as well, can't be an issue with the -5v, isn't it?

Very likely.

That boardset run for Midway (and I'll even say more specifically MKII) is extremely fickle. It hates anything but absolutely perfect power and resolution on the monitor.

It's a major pain in the ass. I've lost two MKII soundboards over the years.

Check the connections on the ribbon cable as well. They get old and may lose contact. Reseat the whole connector on both ends. I've seen that occur a few times.

theMot · Mar 5, 2015

What voltage is it supposed to be set to?

chinitosoccer · Mar 5, 2015

@theMot This board needs 5.3v,

I think I fixed the rebooting problem, it was the main cpu socket that was a bit dirty, a bit of rubbing alcohol with a tooth brush and now the game starts at the first try, but the sound is still doing the same, I will try with another sound board from another T-unit and see if that changes something.

chinitosoccer · Mar 5, 2015

I think found the problem with the sound, it seems that the previous owner was doing some repairs on the board and for some reasson he swapped the oscilator in charge of driving the ADSP, causing it to run at a faster clock, it appears like I'm gonna need a 10mhz one, at least that's how is listed on the system16 webpage: ADSP 2105 @ 10Mhz

Can anyone with this same board confirm if this inforrmation is correct?

ReplicaX · Mar 5, 2015

chinitosoccer said:
I think found the problem with the sound, it seems that the previous owner was doing some repairs on the board and for some reasson he swapped the oscilator in charge of driving the ADSP, causing it to run at a faster clock, it appears like I'm gonna need a 10mhz one, at least that's how is listed on the system16 webpage: ADSP 2105 @ 10Mhz

Can anyone with this same board confirm if this inforrmation is correct?

U1: ADSP-2105 KP-40
Y2: 10Mhz Crystal

If its not 10Mhz thats your issue.

Your RAM issue is likely cause there is no batt. So you should be in DIP Coin anyway.

DIP 2: SW1 = OFF

chinitosoccer · Mar 5, 2015

Thanks, how can I meassure the crystal? is that even possible? the lettering in this one is covered with solder, where did you get the dipswitch settings for mk2? those that I have found through a google search were either wrong or for MK1.

ReplicaX · Mar 5, 2015

chinitosoccer said:
Thanks, how can I meassure the crystal? is that even possible? the lettering in this one is covered with solder, where did you get the dipswitch settings for mk2? those that I have found through a google search were either wrong or for MK1.

You can measure crystals with an oScope. I got the dipswitch settings from my MKII Manual.

mikejmoffitt · Mar 5, 2015

Just because an IC is run at a specific frequency f does not mean the oscillator runs at f. I would check against a known good board for what frequency its oscillator is. I'm not saying that isn't a possible cause, but it would not be good to jump to conclusions. The Neo-Geo CPU runs at a division factor of 2 off of the master 24MHz clock. There is a chance the oscillator is meant to be 20MHz, 40MHz, etc. and is divided for the ADSP.

ReplicaX · Mar 5, 2015

mikejmoffitt said:
Just because an IC is run at a specific frequency f does not mean the oscillator runs at f. I would check against a known good board for what frequency its oscillator is. I'm not saying that isn't a possible cause, but it would not be good to jump to conclusions. The Neo-Geo CPU runs at a division factor of 2 off of the master 24MHz clock. There is a chance the oscillator is meant to be 20MHz, 40MHz, etc. and is divided for the ADSP.

If the Crystal is at the wrong f then what the ADSP does is irrelevant as the CLKIN is wrong. The ADSP on this board was designed around a 10Mhz CLKIN. Checking the CLKIN off the Crystal would be the first troubleshooting step and is common sense, unless it has an overtone circuit, which you would have to calculate.

However, looking at the schematic it has no overtone circuit, looks like a standard Pierce.

ECZangief · Mar 5, 2015

mikejmoffitt said:
Just because an IC is run at a specific frequency f does not mean the oscillator runs at f. I would check against a known good board for what frequency its oscillator is. I'm not saying that isn't a possible cause, but it would not be good to jump to conclusions. The Neo-Geo CPU runs at a division factor of 2 off of the master 24MHz clock. There is a chance the oscillator is meant to be 20MHz, 40MHz, etc. and is divided for the ADSP.

Hmm. I can see what you're thinking, but your'e missing something.
Personaly I've never seen an AUPAGE to set that high. I'd check the ABQ 0hmz on a Romsputen, if only to rule out an X-Factor. Set the credentials firmly as a precaution. If you don't have a Romsputen, use something different, like a toaster. Humm a few bars from your favorite musical, or it won't work.

Thanks.

chinitosoccer · Mar 6, 2015

I know the crystal isn't stock because the solder points are a mess, it has big globtops of solder on each leg, and stains of flux on the solder side, I have to go and pick up another MK2 sound board today. if that solves the problem then I'll look into replacing the crystal.

chinitosoccer · Mar 7, 2015

It's fixed! I removed and cleaned the crystal and it reads 12 mhz, I swapped it for a 10mhz one and now the sound is working at the correct speed/pitch, now I have a spare soundboard which I don't know what I'm going to do with it.

ReplicaX · Mar 7, 2015

chinitosoccer said:
It's fixed! I removed and cleaned the crystal and it reads 12 mhz, I swapped it for a 10mhz one and now the sound is working at the correct speed/pitch, now I have a spare soundboard which I don't know what I'm going to do with it.

There you have it. Nice job Chinito, enjoy!

Mortal Kombat 2 pcb all kind of problems

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