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Strider repair Log

Jan 072016

I received a CPS1 Strider for my personal collection (B and C board only) from my friend Roger this week. The board was sold as not-working, and when I fired it up, it was sure enough not working:

As you can see above, there were heavy jail bars present in the background sprites. Experience with CPS1 hardware told me one of three things was going on – bad C board, bad mask roms or bad/corroded sockets. The C board is the B-01 PPU variety, which is functionally equivalent to the B-21 PPU. Since I have known working B-21 boards on hand, this was an easy starting point. Swapping the board did not have any effect, so I knew it was either the mask roms or the sockets at fault.

In order to verify the mask roms, I removed them from my board, and set my Superpro 580u programmer to HN27c4000g (which are pin for pin compatible the HN6204P mask roms capcom used). Strider is a very strange board in that the etched rom numbers DO NOT match with the PCB. I turned to mame source code to determine which rom file correlated to which mask rom. Sure enough, the FIRST rom I tried to verify complained about Pin 12 not having connectivity. Some times when you read mask roms as eproms, there are pins internally disconnected, and that is OK. This was not one of those times. I referenced the HN27c4000g datasheet to determine that Pin 12 was actually for Address 0. This address line is 100% required for the rom to function.

Today happened to be my lucky day. I had ONE and only ONE 27c4000g eprom on hand. Burned the mame binary to the rom, popped it in Strider, and the game was back in action!

I played a few games, did not observe any other abnormalities. I wish all repairs could be this easy! Another great Capcom game has been preserved!

CPS2 Xmen Children of the Atom repair log

Jan 072016

I bought a really trashy copy of Xmen Children of the Atom off of eBay out of sheer curiosity. The auction’s description indicated that the B board was bad, and had caused the previous owner’s power supply fuse to blow. WHOAH! Sounds like more than just the normal suicide issue most “dead” CPS-2 boards have. I decided to take a gamble and won the auction for a whopping $8.

Upon arrival, I opened the PCB and was greeted by an old abandoned mud-wasp nest. GROSS! I gave the PCB and shell a good bath to get all of the nest remnants off of it. At a first glance, outside of being dirty, the PCB looked to be OK. The original battery was still in place, and read 0.0v (thankfully it did not leak). Clearly this board had suicided. I decided to try out Razoola’s suicide tester in rom socket 3 (very handy). When I booted up the game, I could hear the 1st track of the audio playing (a good sign), however the diagnostics that should display were COMPLETELY blank. I had an entirely black screen.

At this point I decided it was worth while to try the decrypted Xmen program roms on my PCB, just to see if I got any signs of life out of the B board. After installing the Team Avalaunch decrypted rom set, the game would boot, eventually show the “mild animated violence screen”. After displaying that screen, the CPS2 would hang, reboot and repeat. No other sprites or text would display outside of the animated violence screen and it would not progress past that portion of the demo loop.

I took the board into direct sunlight to see if I could find any discreetly burned components. Sure enough, the diode at position D1 was burned clear in half. Replacing it did not have any effect on my symptoms, however it did give me a clue that a major power fault had occurred on the board. Previous experience with the CPS2 told me that the issue was more than likely due to a bad custom capcom IC. Also from previous experimenting and experience, I know the custom Capcom IC DL 1927 (CGA) at position 7M is partially responsible for graphics generation. Since that was pretty close to the burned diode, this became my prime suspect.

I pulled a parts CPS2 B board out, and decided to attempt swapping the QFP120 DL 1927 IC.

MUCH to my surprise, after swapping the IC and verifying there were no bridges or floating pins, Xmen fired RIGHT UP. All graphics restored. Not bad for an $8 eBay pickup 🙂

In retrospect, I think the original owner may have put the Jamma edge connector on slightly misaligned, and sent 12v down the 5v power rail, taking out diode D1 and the QFP at 7M. Another great Capcom game has been preserved!

Forgotten Worlds repair log

PCB Repair Logs, Repair Logs 3 Responses »

Jan 072016

I received a very nice condition Forgotten Worlds PCB from a friend of mine, intended for my personal collection. The PCB showed up in spectacular shape, there wasn’t even any dust or grime on it. All original stickers and labels in tact. In fact, this is the first board on the CPS-1 platform where I have seen serial numbers on the A and B board that match:

Sadly, when I fired up the game, the colors were all wrong. Previous experience with the CPS1 told me this was likely a bad custom Capcom IC, or a bad ram chip.

Due to the nature of the CPS1 hardware, and the fact it is very hard to diagnose the motherboard (the A/B double stacked board makes it very hard to probe), I generally just swap the motherboard from a lesser valued game. In this case however, since the serial numbers match, repair was the only option!

With the assistance of the CPS1 Old Hardware Revision A Board schematic posted right here on Jammarcade, and some critical input from Caius, I was able to determine with high certainty where the fault was. In my case, the ram that controls RED was the prime suspect (at location 2D). I did not have any Sony CXK5814 ram chips on hand, but I did have Toshiba TMM2018 which is equivalent. Without hesitation I swapped the IC.

And…. SUCCESS!

If you were wondering, yes I am enjoying this classic with the proper “Rolling Switch” spinner controls.

Another copy of this wonderful Capcom shooter has been preserved!

Final Star Force repair log

PCB Repair Logs, Repair Logs 2 Responses »

Jan 062016

Recently got this Final Star Force PCB with graphical glitches on the sprites.

This game uses a motherboard (pictured above) and has a romboard on the other side fitted with no other chips than the game’s ROMs.

All the ROMs were tested ok on my programmer and cleaning the connectors and looking at the signals, everything seemed fine with that romboard.
The motherboard has a rather simple layout with a lot of RAMs, some ASICs and a few TTLs. After a few hours looking for suspicious signals, I finally found the faulty ones.

There is a row of 12 Sanyo LM33464G RAMs (64k-word x 4-bit). Two of them were bad (the ones at IC22 and IC33). Piggybacking them with new ones partially brought back clean sprites, even if there were a few glitches remaining. These glitches totally disappeared after replacing the RAMs.
As these models of RAMs are a bit uncommon, I took compatible TMS4464 as replacement (highlighted in red):

Here are before and after pictures:

Gunbird PAL dump added and Rohga PAL set tested

PAL Updates Comments Off

Jan 052016

In the past days the user ‘NeTaXe’ posted a request on JAMMA+wanted forum, he was looking for the PAL chip marked ‘3021’ @U69 that was missing from his Gunbird PCB.I accepted his appeal and in my turn requested dump of this PAL on Dumping Union MAME mailing list.Some hours later our member Corrado Tomaselli kindly posted it (as well as others from various Psikyo PCBs) so ‘NeTaXe’ could revive his board.Thanks to Corrado for providing the dump and to ‘NeTaXe’ for testing it .

Today I could successfully verified the Rohga – Armor Force untested PAL dumps made from ‘Muddymusic’ some time ago.I actually tested them on a Wolf Fang – Ku-U-Ga 2001 PCB (japanese version of Rohga) confirming dumps works for both versions.

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