December 2015 – Page 3 – JAMMArcade.net

Street Fighter II – The World Warrior repair log

Dec 152015

I got this Street Fighter II – The World Warrior PCB from my friend Joachim for a repair :

SFII_PCB

Gameplay was fine (strange thing since CPS1 hardware is higly unreliable) but sound samples were missing or played randomly :

Samples are played by an OKI MSM6295 chip located on A-BOARD which take data from a ROM on the B-BOARD, looking at it I noticed some sign of reworking with a jumper wire too:

MSM6295@14D

Continuity of traces was good so I opted for replacing the chip :

MSM6295@14D_replacing_

This restored the sound samples, end of job.

Gryzor repair log #1

Dec 142015

First I would like to thank hezkezl and channelmanic on the KLOV forum for their help when I started diagnosing this Gryzor PCB last Year.

I finally got it repaired…

1) I got first stuck at this screen on boot:

gryzor0

Dumping the program ROMs at 17A and 18A and comparing them with the ones from MAME revealed the checksum for the one labeled 633J2 at 17A was bad so I burned the rom from MAME on a 27C512 EPROM and put it in place but no changes.

While checking the PCB with a scope, I traced a suspiciously weak signal from a couple of TTLs (which seemed ok) to a Fujitsu MB8464A RAM. Pins #7, 8 and 9 on this RAM were not pulsing (signal was stuck at 1,7 V).

These pins are address lines. They are connected to:
– Pins 7, 8, 9 on 18A and 17A (program ROMS)
– Pins 9, 10, 11 on 22A (63C09 CPU)
– Pins 114, 115, 57 on 10E (custom chip)
– Pins 114, 115, 57 on 18E (custom chip)
– Pins 1, 2, 3 on 14D (LS138 – Address decoder for I/O ports)

Replacing the LS138 at 14D didn’t change anything, not really surprising as it was related to I/O (but I didn’t really know that back in the time when I did it) so next I decided to replace the 63C09 CPU at 22A… And the game booted ! …with big graphical issues and no sound:

gryzor2

2) Graphics roms are the 4x 40 pins mask roms located at 7D, 7F, 16D and 16F. I’ve read online some people having problems with these chips and needed to replace them. The content of these roms is 256kb but I only had 512kb 27C400 EPROMs (equivalent pinout to mask roms) so I needed to double the size of each original 256kb roms to fit my 512kb EPROMs. A few tries revealed I had 3 bad roms (the ones at 7F, 16D and 16F) among the 4. All the graphics were now fine:

gryzor3

3) Good progress, but still no sound…

There are 2 chips in the sound part (located at 11A and 11B) that have their reference writings scrubbed, probably in factory to avoid bootleggers reproducing it. I’ve looked online to see if I could find pictures of other PCBs that could still have these labels visible, but all the ones I found had their writings scrubbed.

Anyway, it looked like these 2 chips were the sound generating chips. Looking in the MAME driver and on datasheets revealed it was a YM2151 coupled with a YM3012 D/A converter.

Looking at the pins of the YM2151 with a scope, I noticed there was no output signal on it (pin #21) while most of the other pins on the chip had pulsing signals. I desoldered it to put a new YM2151 in place and got a pulsing signal on the output pin… But still no sound.

I then started looking at the pins of the 63B09 sound CPU at 15A and found 2 dead signals at pins #16 and 18. These are address lines so I suspected the CPU and changed it. The sound was finally back. Everything is working fine now !

Here is a picture of my PCB with all the bad chips I replaced in red:

gryzor4b

Heavy Unit repair log #1

PCB Repair Logs, Repair Logs Comments Off

Dec 142015

I got a dead Heavy Unit PCB with a white screen on boot:

hvyunit1

Looking at the MAME driver for that game I could see where the program roms were located (5C for the main program rom and 5P for the sub program rom).
I started probing around the CPUs and program roms. The CPUs (2 x Z80) seemed active and the program roms had pulsing signals on most of their pins. A few were inactive and connected to nearby GALs (labeled MD-500 and MD-501). All the I/O pins were stuck low on these two GALs while they had pulsing inputs.

There are 3 GALs in total on that board, MD-500 is connected to the main program rom, MD-501 is connected to the sub program rom and MD-502 is connected to the sound rom.
Surprisingly all these 3 GALs had inactive I/O pins. I got a working Heavy Unit PCB from a friend, compared the signals on the GALs and saw that almost every I/O pins were pulsing on the 3 GALs.

These GALs were not available online so I started desoldering them on both PCBs.
I put sockets on the dead PCB, socketed the GALs from the working board and the game booted ! …but with partially missing graphics (I had colored squares instead of sprites):

hvyunit2

Looking at the PCB I supposed the main program rom at 5C was not original as it had no label. Dumping it revealed it was from a US version. Looking at the MAME driver, I could see that every of the 4 versions dumped in MAME had a different ROM layout and my version was not dumped (the numbers on the labels were not in MAME). Particularly, there was a 512kb ROM at 2F on every versions in MAME that wasn’t soldered on my PCB, although I found its content spread on 4x128kb ROMs at other locations. The main program ROM was probably looking at the wrong location so I soldered a socket at 2F to put the 512kb ROM (from one of the MAME dumped versions and labeled B73_08) and the sprites were back. 🙂

hvyunit3

Here is my PCB with the added 512kb EPROM from MAME at 2F (equivalent to B73_17 + B73_18 + B73_19 + B73_20 on the left):

hvyunit0

ps: I’m still looking for the original program ROM for my PCB (labeled B73_24 and located at 5C) to be dumped so I could remove the 512kb at 2F and use the original 128kb ROMs already present on the board. I suppose it is a japanese version.

ps2: I wanted to dump the GALs from the working board but they were protected. To dump protected GALs I needed to use a method by Charles MacDonald. First, I used this adapter in order to read my GALs as 27C020 EPROMs: https://techno-junk.org/files/adapter-v2.png
Then, I used PD.EXE and WinCUPL to recreate the GALs from my raw dumps: https://dreamjam.co.uk/emuviews/readpal.php
These GALs are now available on https://www.jammarcade.net

Irem and Konami PAL dumps update

PAL Updates Comments Off

Dec 132015

In the past days the user ‘PJW’ sent in a couple of PAL dumps from an original IREM Ninjia Baseball Bat Man PCB.These PALs seems to be specific to this game and are located on the ROM board.Original devices were two PAL16L8 whose dumps have been converted by him into GAL16V8 with PALTOGAL utility and successfully tested on PCB.Thanks to him.

Yesterday I dumped the PALs from an original Konami Aliens PCB.The devices, two PAL16L8, were unsecured so I could read them in a programmer and then convert into GAL16V8.Both dumps have been successfully tested.

Space Invaders (Taito) 3-Layer repair log #1

PCB Repair Logs Comments Off

Dec 102015

I was recently given a Taito 3-Layer Space Invaders boardset by a friend to look over. The problem was that it was not running, completely dead with a clicking sound coming from speaker (sounds like watchdog barking to me).

I powered up the PCB stack on the bench and checked the status of the 8080 CPU. I could see right away from probing pin 19 (SYNC) that the clock circuit was not running.

On the ROM board, I could see that the crystal was intact, so I checked the 74S04 (IC1) which I was sure was drives the clock next to the crystal. I found that most of the pins were floating. Replaced it and I now have a clock (note to myself, 74HC04 will not work), watchdog no longer barking but still no display.

ace_si_1

On further probing, found a bad 74161 counter at location IC6 with pins 11 to 15 stuck HI. Replaced this and I now have a display, but it appears to be doubled up;

ace_si_3