November 2014 – Page 2 – JAMMArcade.net

Splatterhouse repair log #2

Nov 152014

First of all I want to thank JROK for providing me all the technical info and allowing its public release, without his help I would not have ever made.Let’s start with the story.

Some time ago a friend of mine sent me his Splatterhouse PCB bought as working saying it got stuck upon boot on ‘ROM TEST START!! PLEASE WAIT..’ message displayed upside down on a screen filled with red zero.So I started to investigate on the net and found that usually this kind of issues are caused by a faulty custom chip marked ’64A1′ @M4 on ROM board.This was confirmed by swapping this IC in another CPU board of Galaga88 with this missing component , in this case I got an ‘EEPROM ERROR’ message which is a further proof of the fault.

Thanks always to JROK we know that this ’64A1′ custom IC is nothing else than a HD63701 MCU with the exception of two custom opcodes not present in original part.You can go deeper into technical reading here:

https://www.jrok.com/hardware/cus60/cus60_an_owners_guide.html

So, programming a blank HD63701 MCU with the available dump from MAME won’t work due the presence of these two custom opcodes.So, patching a ROM is needed.

In the specific you have to change three bytes in the ROM “VOICE0” at a specific offset.For example : in Splatterhouse the offset is $FA8B and the new HEX values are “20 01 56”.

The string to search for in HEX is “B7 C0 00 6E 00” and the first 3 bytes must be changed to “20 01 56”

The patch seems to be needed at offset $FA8B for most games, but not all. Here’s a reference table :

Tank Force – $FA29
Blazer – $FA8B
Dragon Spirit – $FA8B
Galaga 88 – $FA8B
Marchen Maze – $FA8B
Splatterhouse -$ FA8B
Rompers – $FA8B
Blast Off – $FA8B
World Court – $FA8B
World Stadium (and WS ’89, WS ’90) – $FA8B
Bakutotsu Kijuutei (Baraduke 2) – $FA8B
Beraboh Man – $FA4E
Dangerous Seed – $FA8B
Face Off – $FA29
Pisto Daimyo no Bouken – $FA8B
Puzzle Club – no voice ROM !
Quester – $FA1B
Souko Ban Deluxe / Boxy Boy – $FA8B
Yokai Douchuuki (Shadowland) – $FA8B

So, it was only matter to find some real blank HD63701.My first attempt failed since I bought as new some ICs that they turned out to be already programmed and, since they were the plastic HD637B01VOP one-time-progfammable version, they were unusable for my purpose.But then I was luck and found some HD63701VOC UV erasable ones:

So, it was only matter to program one of these MCU with MAME dump using my Hi-Lo Systems ALL-11C EPROM programmer and, at the same time, replace the ROM ‘VOICE0’ with the properly patched one.Once done, I had confirmation of what the good JROK said about. Operation ‘NAMCO custom 64A1 replacement’ accomplished.

Rainbow Islands repair log #3

Nov 122014

First of all I wanna thank the people who donated me this (and other) PCB : “mille grazie” to Mr. Giuseppe (a long-standing arcade operator of my town) and his nice daughters Elena and Antonella!

Now, let’s begin with the log.

When I got this PCB in my hands, I immediately tought it was a Rainbow Islands one:

But I was wrong, it actually was the Extra version (different ROMs and C-Chip).Before start the troubleshooting, I resoldered a wonky TC0070RGB module:

Once powered on, I got a solid white screen with a clicking sound indicating that the watchdog circuit was active:

There was clearly some trouble in main code execution so I started to test with my logic probe the two WORK RAMs and I found some data lines stuck HIGH on the 6264 SRAM @IC25.I desoldered the chip and out-of-circuit test confirmed it as bad:

With a new RAM the board succesfully booted but graphics (tiles and sprites) were all blocky:

This board (and other Taito ones on similar hardware ) uses two custom chips in PGA package which generates sprites (the one marked ‘PC0900J’) and tiles (the ‘PC080SN’).They respectively address GFX ROMs through a couple of 74LS373 latches.Probing the 74LS373 @IC29 I found that all the outputs were absent.So I piggybacked a good one and tiles were restored but sprites were always blocky:

So, I went through the 74LS373 @IC18 and found it had output PIN19 stucked LOW while its input was toggling.Piggybacked this and also sprites were restored.Desoldered the two 74LS373 and they were indeed bad:

Replacing them both back this game to its former glory!

KOFNW and METAL SLUG 6 Atomiswave conversions released

General Comments Off

Nov 102014

Darksoft has released the latest Atomiswave conversions to the masses.
You can grab them here
https://64darksoft.blogspot.co.uk/2014/11/releasing-kofnw-and-metal-slug-6.html

Ive personally played Metal Slug 6 all the way through on several occasions and it was perfect.

Enjoy

Dyna Gears PAL dump added

PAL Updates Comments Off

Nov 092014

‘coolmod, one of our finest members, sent in the PAL dump from his Dyna Gears PCB.Dump was obtained from an unprotected GAL16V8 device and it’s tested as working.Thanks to him for this submission.

Testing Bubble Bobble ROM banks with Fluke 9010

Guides Comments Off

Nov 012014

Recently I was talking to IronGiant about testing the “a78-05-1.52” ROM on an original Bubble Bobble PCB with the Fluke 9010.
As the ROM is banked we cannot test this ROM in one go.
Here is how we managed to do it.

0) Before we do anything we need to disable the watchdog otherwise this wont work properly. This is done by cutting the track on JP6 on the solder side (thanks to IronGiant for the info).

1) Take the ROM dump for “a78-05-1.52” and split it into 4 files using a HEX editor or similar. Each file should be 0x4000 bytes in size.
Run all 4 files through one of the signature calculators that can be found online and make a note of them.

2) The bankswitch lies at address 0xFB40 in the address map.
You need to write a value between 4 and 7 to select the relevant bank.
So start by writing 4 to address 0xFB40.

3) Next we need run a ROM check on between address 0x8000 & 0xBFFF.
This signature should match the first 0x4000 bytes of the ROM.

4) Repeat steps 2 and 3 a further three times incrementing the value written to address 0xFB40 each time. If all the signatures match then the ROM is good.

The ROM is different across each version of this game so make sure you compare it with the right file.
This method will probably work on the bootlegs too with some minor changes to the procedure.

Newer Entries