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Big PAL dumps update

PAL Updates Comments Off

Oct 292017

Today we have a massive update.Dumps came from the following PCBs:

Athena bootleg

Porchy dumped the PALs from a copy board and successfully tested dumps back on board.Corrado Tomaselli confirmed dumps are working also on the original PCB.Devices were all unsecured (two PAL16L8 and one PAL20L8) and they have been reversed into GAL devices (for the 24 pin one both GAL20V8 and GAL22V10 replacement available).Thanks again to both them.

Cyberball (prototype with serial #0002)

Dumps were provided by ‘coolmod’ on Dumping Union list from an early revision/protoype of board.Devices were all unsecured PAL16L8.We mark them as “assumed working” since we have no means of testing GAL replacements.Thanks to him.

Locked ‘n Loaded

256KB binary PAL dumps provided by Smitdogg on Dumping Union from a faulty board.I reversed them into GAL fuse map which we mark as ‘untested’ until testing on a working PCB will be done.Thanks to him.

Gokidetor (a mechanical wack a mole type game by Taito)

Dumps provided by Smitdogg on Dumping Union, devices were all unsecured.We mark them as “assumed working” for now.Thanks to him.

Bobble Bobble (bootleg of Bubble Bobble)

I dumped and reversed into GALs the three PALs from this one layer bootleg.All dumps matches the two layer version (dumped by Porchy some time ago) except for one which has slightly different equations.

Tecmo World Cup ’94

Board has six PALs but I was able to dump and reverse into GAL only the one @U64.

Pipe Dream

I dumped the PLDs from a dead board.Out of four devices present one was registered so not dumpable.Dumps are untested for now until we can test them on a working board.

CPS1 ‘DASH’ A-BOARD repair log

PCB Repair Logs 2 Responses »

Oct 252017

Received this faulty Capcom CPS1 A-BOARD, actually the ‘DASH’ revision with a 12MHz oscillator in place of 10MHz one:

Board played with good graphics but sound samples were completely wrong and randomly played, here’s a video made with a Captain Commando B-BOARD/C-BOARD:

PCM samples are played by an OKI ‘MSM6295’ IC which addresses two 1Mbit devices (located on B-BOARD) and reads back their data.Judging from flux residuals the IC was previously reworked on this board as well as other components of audio circuit:

For first I tested all traces to/from it, all was OK.So, most likely, the IC was bad, no wonder since it’s a prone to failure part.I removed it:

Cleaned the PCB from flux and installed the spare:

Time to test:

Board fixed.End of job.

Arkanoid repair log #1

PCB Repair Logs Comments Off

Oct 212017

Got this original Taito (licensed to Romstar) Arkanoid PCB for repair:

Board uses the Taito Classic pinout (used on other games like Bubble Bobble, Elevator Action, Jungle King) so I had to build a proper JAMMA adapter:

On power up I was greeted by this static screen:

The string “WOVO VEM EVVOV” reminded me “WORK RAM ERROR”.I had confirm of it opening one of the program code ROM with an HEX editor:

The WORK RAM is located @IC15 in form of a 2K x 8-bit device but piggybacking it had no changes.There are other two 2016 static RAMs @IC57 and IC58 :

When I went to probe the one @IC58 I found the data bit 2 (pin 11) stuck high:

This is tied to pin 9 of a 74LS245 @IC42 for exchanging data with the other one @IC57 which, according to MAME memory map, is the VIDEO RAM shared with Z80 main CPU:

1   1   1   0   *   *   *   *   *   *   *   *   *   *   *   0       RW  2016 SRAM@IC57
1   1   1   0   *   *   *   *   *   *   *   *   *   *   *   1       RW  2016 SRAM@IC58
AM_RANGE(0xe000, 0xe7ff) AM_RAM_WRITE(arkanoid_videoram_w) AM_SHARE(“videoram”)

PIN11 of the transceiver was, instead, properly toggling :

Piggybacking it restored correct error message:

I pulled the 74LS245 and it failed the out-of-circuit test exactly in the involved gate:

Replacing it fixed the board completely.

Sukeban Jansi Ryuko (317-5021) decrypted

Decrypted Updates Comments Off

Oct 212017

Hi there !

System 16B version of Sukeban Jansi Ryuko (317-5021), using a FD1089B is now available , you can grab it from the dedicated page. I don’t think a lot of people will be interested in it, as it’s a mah-jong game using a dedicated controller …

Cheers !

Toki double repair log

PCB Repair Logs Comments Off

Oct 072017

A quick double repair log of Toki, a funny and addictive platform game released by TAD Corporation in 1989.

The first PCB:

On power up it was stuck on a blank static screen:

Doing a visual inspection I noticed some scratches on solder side:

Using my multimeter in continuity check I found a couple of severed traces in the 68000 main CPU area:

After patched them the game successfuly booted:

But sound was absent, this was due missing YM3812 OPL chip and custom SIL ‘HB-41’ module:

I finished the repair installing the missing components, this restored full sound.Board 100% working again.

The second PCB:

Board booted but backgrounds graphics were corrupted and flashing :

Also here I found a broken trace on solder side:

This restored graphics:

But, while I was testing the board, suddenly I lose sound and I could no longer coin up.The two issues are related each other since on this hardware the Z80 CPU commands the sound system but also handles coins.Indeed, probing it revealed a stuck signal on CLOCK pin 6 where a 3.579545 MHz one should be:

Looking at hardware, the clock is derived by a 14.318 MHz quartz then divided by the custom ‘SEI80BU’ (which also does interface between main and sub CPU) and lastly divided again by a 74HC74 (14.318/4= 3.5795)

I replaced the quartz with no luck , the 74HCT74 was not receiving any 7.159MHz signal so, for exclusion, the ‘SEI180BU’ had to be the culprit.I removed it and took the spare from a scrap Raiden PCB:

This restored sound hence the custom was really bad:

Double repair accomplished.

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