JAMMArcade.net – Page 114

Pac Man single ROM board

General Comments Off

Mar 042016

After fixing a couple of Pac Man PCB’s recently, the owner of them very kindly let me keep one of the boards. The only problem was it had been stripped of the ROM’s and customs.
Now the customs are no longer a problem for me but the ROM’s are of the 2532 variety and I only have a couple of them free.

As luck would have it user ‘philmurr’ on the UKVAC forums has made a nice little drop in replacement that fits in the Z80 socket and lets you use a single 27c128 EPROM in place of the 4 x 2532 program ROM’s.
I got it today, assembled and fitted it without issues.
20160304_184754
20160304_200325

Game plays as you would expect.
20160304_200330

A couple of caveats. There are a few wire link mods needed to the PCB due to an error but these are well documented in the instructional PDF and the boards are so nicely priced that it really doesn’t matter too much, at least not to me.
The other potential issue is that if your PCB is fitted with the TTL custom replacements then this board just isn’t going to work for you as the custom covers the original Z80 socket.

Really happy with this so thanks to Phil.

Quartet repair log

Mar 042016

Here is a recently repaired Quartet running on Sega pre-system 16 hardware.

quartet1

The 3 replaced chips are highlighted in red. I will explain every step of the repair process below.

1) The game was booting to a garbled screen:

quartet2

The 74LS04 located at 1H (an inverter, manufactured by Fujitsu) had good clock signals on entry pins 11 and 13 but had floating signals on outputs pins 10 and 12. Replacing the chip changed the result on boot…

2) I then got a screen with garbled graphics but with a countdown appearing at the center.

quartet3

This is normal on pre-system 16 games. Normally, after reaching 0, the game is booting. Here, I got a black screen after the countdown.

I noticed that the reset pin on the 68000 had a square looking wave signal, which was pretty weird (it should be a linear signal at +5V). The chip that generates the reset signal is a MB3771 located at 1G (again, manufactured by Fujitsu). Probing its pins made the game sometimes booting. I replaced it by a new 3771 chip and the game was now starting normally.

quartet4

3) The game was working and playing fine except for the FM sound that was inoperative (only the voices could be hear). It was due to the YM3012 located at 1B (a DAC). It had good looking signals on its inputs but nothing seemed to get out of its outputs. After replacing it I got the FM sound back.

Now the game is fully working.

Fluke 90 QuickTools 2.0 update

General Comments Off

Feb 282016

I’ve uploaded the updated version of QuickTools 2.0 (formerly Fluke 90 Controller).
There are quite a few differences. The main ones are its quicker, has some status indicators for the Trace functions and has preliminary script support (which doesn’t work too well right now).
qt2

If anyone has the Z80 version of the Fluke 90 for sale then I would be interested in buying it if the price is right.

Fighting Fantasy PAL dumps added

PAL Updates Comments Off

Feb 272016

Today I’ve dumped the only PAL from a Fighting Fantasy PCB, a weapon based fighting game from Data East released in 1989 (the game is also known as Hippodrome outside Japan).Dump has been successfully tested in a GAL16V8 targeting device.

Rainbow Islands repair log #10

PCB Repair Logs 2 Responses »

Feb 252016

Another Rainbow Islands PCB to repair.

This one had issues with the sprites which were broken up and seemed to be repeating, looked very much like a stuck bit on the sprite addressing;

IMG_20160224_112137583

IMG_20160224_112142174

All tiles and background graphics were fine, so I knew it was something to do with the sprite circuit.

The first thing I did was to look at the area where the sprite data is read from the two eproms. The two 74LS244 buffers checked out fine, but one of the 74LS373 Octal Latches had an output pin stuck HI (pin 9);

IMG_20160224_112155598_HDR