Fixing Moonwalker Issues

c0nn0r

If I could have, My time back, I'd keep it in ma'
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Hey gang, I have a desuicided Michael Jackson’s Moonwalker PCB here that I bought as non-working, and am making the attempt to fix this bad-boy myself.

There are three separate issues:

(1) Missing foreground sprites (bad IC-17 - Sony CXK5814 chip)
(2) PCM audio from the rebranded Ricoh RF5C68 smt chip (rebranded as ASSP 5C68A) is garbled
(3) Board fails half of the V.D.P. test. I’m not sure what this is, nor can I see any adverse effects on the graphics (aside from the missing foreground sprites) - perhaps this is a symptom of the bad IC-17?

Questions:

(1): Where can I buy working replacement parts for the chip st IC-17 - Sony CXK5814 or compatible?
(2): Where can I purchase a working replacement RICOH RF5C68 chip?
(3): What the deal with failing half of the V.D.P. test?


Here’s what I know thus far from my research and testing:

(1) Foreground graphics issue is likely tied to a bad work-ram at IC-17. I know this because the excellent memory test SEGA provided told me (and per this post: https://forum.arcadeotaku.com/viewtopic.php?t=11206). It looks like a previous owner attempted to fix this issue as the current chip at IC-17 is socketed. Looks like they just socketed the same chip as it matches the one at IC-16. I took out the chip, cleaned the pins and re-seated it. Still comes up as bad.

(2) PCM audio from the RICOH sound chip is garbled. FM synth still working properly, so the z80 is probably good. Pretty sure that I need to replace the RICOH chip (as per: http://www.jammarcade.net/michael-jacksons-moonwalker-repair-log/), but am having a tough time sourcing a replacement part. I’d prefer to buy a NOS chip, but as I understand it the same chip is used in the SEGA CD, so I may have to take one from scrap.


I’m hoping that if I can manage to replace these chips I will have a working Moonwalker.

Bad chip at IC-17
IMG_7313.JPG

Failed half of the V.D.P. test?
IMG_7314.JPG
 
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segasonicfan

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Damn, best of luck. This sounds similar to a broken Moonwalker I gave up on awhile back. Doing lots of Internet searching to Source obscure Parts is definitely a pain. Ali express has a lot of stuff, but they also stole my credit card last time.
 
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Xian Xi

JammaNationX,
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For the audio, you just need an 8751 with the right key. Just make sure it’s the 8751 for the set you have. You should be able to get both from buyicnow
 

c0nn0r

If I could have, My time back, I'd keep it in ma'
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Thanks guys. This is some good info.

I have a new baby in the house (first time father here), so it will take me some time to get all this together and attempted. Mark my words though, I will get some time in the upcoming months, and will post a report of the results.

Again, thanks for the support on this.
 

c0nn0r

If I could have, My time back, I'd keep it in ma'
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For the audio, you just need an 8751 with the right key. Just make sure it’s the 8751 for the set you have. You should be able to get both from buyicnow


Thanks guys. I ordered some multiples of the parts from eBay. I took a look on buyicnow, and they did have the items listed, but the only available CXK5814P was 600m rather than the 300m. The weird thing was that the photo of each version of the IC looked to be the same width, so not sure if they had incorrect listing.

Both items are on the slow boat to Canada, so I will report back in when they arrive with an update.

Thanks again guys.
 
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c0nn0r

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For the audio, you just need an 8751 with the right key. Just make sure it’s the 8751 for the set you have. You should be able to get both from buyicnow

I'm about to receive the i8751 in the mail this week, and just now realize that I need to find my old, or buy a new programmer to flash on the correct key. Assuming I have the US version of Moonwalker I would burn the 317-0158.key from the 'mwalku' set on to the 8751? Does it matter which MAME version I pull the .key from? Sadly I was unable to make a backup of my current 8751 before it died. Is there a better source for these .key files?

Also realized I can't remember where I put my sockets. Need to order some of those too.
 

mainman

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I'm about to receive the i8751 in the mail this week, and just now realize that I need to find my old, or buy a new programmer to flash on the correct key. Assuming I have the US version of Moonwalker I would burn the 317-0158.key from the 'mwalku' set on to the 8751? Does it matter which MAME version I pull the .key from? Sadly I was unable to make a backup of my current 8751 before it died. Is there a better source for these .key files?

Also realized I can't remember where I put my sockets. Need to order some of those too.

Unless you have a really old programmer at your disposal you will need explicitly a D87C51 not D8751
 

c0nn0r

If I could have, My time back, I'd keep it in ma'
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Unless you have a really old programmer at your disposal you will need explicitly a D87C51 not D8751

Thanks mainman. I bought a couple intel D87C51FA-1, so it looks like I have the D'C' units you mentioned. Not sure what the FA-1 suffix means.

Anyone know if there is someone on the forum that I could send these ICs to to have them correctly programmed? I wonder if that would be less of a headache than buying a programmer and doing it myself... Although I do need a programmer eventually.

Here's a pic of the unit I bought:
Screen Shot 2019-05-06 at 9.39.26 AM.png
 

mainman

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Thanks mainman. I bought a couple intel D87C51FA-1, so it looks like I have the D'C' units you mentioned. Not sure what the FA-1 suffix means.

Anyone know if there is someone on the forum that I could send these ICs to to have them correctly programmed? I wonder if that would be less of a headache than buying a programmer and doing it myself... Although I do need a programmer eventually.

Here's a pic of the unit I bought:
View attachment 53921

My programmer can handle it
 

c0nn0r

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My programmer can handle it

I tried sending you a PM, but your inbox is full.

Would it be a terrible hassle for you if I were to mail you these chips for programming? Would be shipping to/from Toronto Canada. Of course I would pay any fees & S&H.
 

mainman

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I tried sending you a PM, but your inbox is full.

Would it be a terrible hassle for you if I were to mail you these chips for programming? Would be shipping to/from Toronto Canada. Of course I would pay any fees & S&H.

I won't charge you anything dude, just pay shipping
 

c0nn0r

If I could have, My time back, I'd keep it in ma'
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I won't charge you anything dude, just pay shipping

That would be excellent - thank you. What's the best way to find your shipping info?
 
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