Moonwalker PCB: All socketed chips removed. What to do?

[ifkz]

I had a few more thoughts about this board today, in the end I decided to start rebuilding it.

The first step was to find a good processor for it, a 12 Mhz 68000. Many years ago a friend pulled one from an old Apple Laserwriter printer that was heading for the scrapheap. It is not a common speed of 68000, so I feel lucky to have it; most are 10Mhz.

The second step was to populate the ROM board with jumpers. I needed sixteen! After a quick dig through my parts box I found them. 2/3rds are black and 1/3rd are white. (Pun intended, one of his songs is Black or White).

Finally, I had a 4Mhz Z80 that I wanted to try in place of the 8Mhz Z80. It pumped out sound, so I guess it will be fine. Same manufacturer as the Shadow Dancer one, Zilog! Z0840008PSC (Shadow Dancer) vs. Z0840004PSC (replacement).

I have a 100% functional Shadow Dancer, another one of SEGA's System 18 games. I decided to move all socketed chips over along with the ROM board to see what would happen.

At first power up I heard music! I also had an out of sync screen. Looking over the bottom of the board, I found a few touching pins. At the second power up I had clean video with insert coin text along with music! All graphics are basic or are missing. I don't know if this is normal for a Moonwalker board trying to run Shadow Dancer, or if I still have a problem to two. I could play the board but speech was missing.

Next step will be programming 17 2Mbit eproms and see what happens.

 

[channelmanic]

If the speech is missing, look for a little blue, yellow, or orange rectangular part not much bigger than a standard white jumper. It's probably broken off the board that has no speech.

It's the ceramic oscillator for the clock for the speech chip.

 

[ifkz]

I'll take a look.
In between posts, I took a picture of the game in self test. Good news, all RAMS pass
I also fitted a heatsink for the amp, a very poorly fitting heatsink.

 

[Womble]

Looks like you have RAM issues, Moonwalker is one of the few games that actually has a decent test routine, others including Shadow Dancer only do a very quick rudimentary test and not on all the RAMs, Shadow Dancer missies SRAMS IC16 and 17. I fixed a SD board recently that passed all its test yet was missing gfx, repair log here..

http://retrocomputermuseum.co.uk/forum/index.php?topic=2290.0

With the Moonwalker rom board installed and I got bad RAM reports for the one of the chips the SD test feature ignored, and once replaced the fault was gone. Once you burn the Moonwalker set you should be able to run its test which will flag up issues I would bet. It may also report bad chips that were shown as good on your test, as it is much more thorough.

The EPROMs you need are cheap and easily found on ebay too Make sure you use the Moonwalker ROMset that doesn't use a protection chip, you wont find a spare one of those in a hurry.

 

[ifkz]

Replaced the four ripped out and punctured caps on the ROM board. I also got my junked CPS1 boards ready in case I find bad RAM per Womble's Alien Storm repair log.

Hopefully my order of 2mbit EPROMS will be here soon so I can really get to work.

I also started a want-to-buy post for a dead or alive complete Shadow Dancer boardset so I can get the PALS I would need to rebuild this. I would say any System 18 boardset, but no one would know what I was talking about

 

[Womble]

Good work, those 4 electros are smoothing caps to keep the power rails stable on the ROM board, checkout this repair I did of a Golden Axe board, very odd beviour of the game when these are missing. It has a URL for a youtube video in the middle somewhere, can't embed on that forum so it has be a url.

http://retrocomputermuseum.co.uk/forum/index.php?topic=2111.0

 

[ifkz]

Your Golden Axe was a lot like my first Golden Axe, but I had to tackle sockets with corrosion, a dead FD CPU, and some halfway working EPROMS in addition to busted off caps. Broken ROM board caps are so common on System16 boards. I also have two boards with broken corners. I wonder why they have been abused so much over the years.

Looking forward to those EPROMS so I can get to work.

 

[trol666]

You'll also need this one for the Moonwalker pcb:

http://www.andysarcade.net/store/index.php?act=viewProd&productId=1281

I might have some Sega PAL's lying around, not sure if they are the right ones.
I'll check it this weekend.

 

[ifkz]

I am hoping not because that CPU is actually part of the protection routine. If you look at the datasheet of the i8751 it is just like the FD-xxx CPU protection, it holds a bit of memory the game looks for before it boots. My Altered Beast has this protection scheme. I wish Sega would have used this for all of their games, at least it isn't a battery based scheme; there is nothing to really die over the years on this specialty CPU.

My solution is to simply put an unprotected set on the ROM board. If I am wrong, this is going to be converted to an Alien Storm really quick!

I sure could use the PALs, this board is missing all of them, I am having to steal them from my Shadow Dancer for the time being, which sucks.

Come on tubes of EPROMS....Come on tubes of EPROMS...

 

[trol666]

I found the following PAL's;
315-5390
315-5391
315-5374
315-5375
315-5430

 

[ifkz]

Cool, let's play name that SEGA Pal!

315-5390 - Shadow Dancer, ding!
315-5391 - Shadow Dancer, ding!
315-5374 - Shadow Dancer, ding!
315-5375 - Shadow Dancer, ding!
315-5430 -???

So close, Shadow Dancer and other System18 CPU boards have six Pals. Thanks for taking the time out of your day to look around for this project.

My order of 27c020 chips came in but they came in a package that was a lot different that I was expecting; half an inch square! I placed a new order of chips with some nice folks in China. So, next weekend I should be able to get a ROM board set together at least.

 

[Solder]

More PAL info, etc here:

http://cgfm2.emuviews.com/txt/s18tech.txt

As for 315-5430 :

"Video layer mixing for 171-5873-02B main board"

 

[channelmanic]

Cool, let's play name that SEGA Pal!

315-5390 - Shadow Dancer, ding!
315-5391 - Shadow Dancer, ding!
315-5374 - Shadow Dancer, ding!
315-5375 - Shadow Dancer, ding!
315-5430 -???

So close, Shadow Dancer and other System18 CPU boards have six Pals. Thanks for taking the time out of your day to look around for this project.

My order of 27c020 chips came in but they came in a package that was a lot different that I was expecting; half an inch square! I placed a new order of chips with some nice folks in China. So, next weekend I should be able to get a ROM board set together at least.

OOPS!

You got PLCC chips...

I have a parts Moonwalker somewhere in storage... I'll have to dig.

 

[ifkz]

OOPS!

You got PLCC chips...

I have a parts Moonwalker somewhere in storage... I'll have to dig.

That would be great! A parts Moonwalker combined with mine might be able to be fixed!

The look on my face when I found those Chiclets sized chips would have been worthy of a photo. One more thing to send back through the mail.

 

[trol666]

Just checked my moonwalker pcb, and it's using the same PALS as Shadow Dancer, the first four from my list.
Then game is running fine, so you could use them

Actually, I'm running Shadow Dancer, Moonwalker and Alien Storm on the same mobo without swapping PAL´s.

 

[ifkz]

That is what I thought, just like Sega's system16b line and Capcom's CPS 1 & 2, the bottom board is (mostly) universal. I would need all six PALs, I hope the junker Moonwalker offered will be semi-complete. We'll see, exciting!

 

[trol666]

If you need any of my PAL's, pm me.

 

[channelmanic]

So far I've dug up a couple of System 16 boards... haven't found my 18 ones yet.

 

[kb0jjn]

My order of 27c020 chips came in but they came in a package that was a lot different that I was expecting; half an inch square!

Mike arcade did the same thing to me. I ordered about 12 z80 cpu chips and what I got in the mail was a Nintendo Reproduction 4-way Joystick w/ 30mm ball top.

 

[ifkz]

I was very happy to finally find my package of EPROMS in the mail today from China. I got to work...

I programmed the Moonwalker set that I made and....I now have a slight change of plan....

It seems like Moonwalker is going to want that extra CPU...or my set was wrong (which I doubt). This was not a real setback though, take a look:

Yes, I'll be running Alien Storm on this board, which is fine by me, and a bit less creepy

After some struggles, broken EPROM pins and different speed chips than advertised I got it to play correctly on my Shadow Dancer board.

This only leaves some rebuilding of the bottom board, which I suspect is bad RAM. I don't have a good way to go through the tests though, this one needs a service switch, which I never wired up in my bartop. Now I am waiting to see what scrap boards will come my way for PALS and other parts. I created a funky heatsink for the amp out of a power supply stand off. I think this project is going to make it Take a look.