Jan 012020
 

Next up in the box of brokenness is a Pacland.

Visual inspection revealed the amp had blown up

I also saw the usual corrosion on the legs of some of the customs

and the socket didn’t look too great either

As you would expect there were some pins missing from the chip when I removed it

I soldered legs on best I could and opted to fire the board up.

This is a good start and using the error code list compiled by my good friend cmonkey I knew that this was a RAM fault.
Checking RAM 9N I found several address lines were dead

Using the schematics I could see those address lines came from a 74LS32 @ 10J

I confirmed the outputs were bad and replaced the chip.
Now I get this when booting

Game is booting but some scroll issues and some jailbars too.
I could affect the scroll issues by pressing on that custom chip I resoldered at the start. I removed it again and attempted to further clean the legs but I just made it all worse. In the end I opted to solder it into a socket.
It looks crappy but it got the job done

Scroll issues fixed I now turned to those jailbars.
This ended up being an easy fix. I removed the ROM at 6T and checked it in my programmer. Bit 5 was stuck high so I replaced the ROM which fixed the jailbars.

Last thing to deal with was the sound. Obviously I wasn’t going to get far without an amp and I don’t have any spares. Lucky for me, my friend Smarty sent me a replacement gratis which fixed the sound and completed the repair.

Thanks very much to Smarty for the amp.

 Posted by at 10:08 pm
Dec 302019
 

Bought a cheap Desert Breaker for my collection which the seller declared as having no sound.

 

This game is running on system18 hardware. Since the sound was totally missing I first tested the z80 which was good and then I desoldered the SRAM which was

a Toshiba @IC79 , normally very unreliable in comparison to other makers and infact it was faulty.

It fixed the sound but playing I noticed that some sprites had missing lines

 

This problem could be either the custom chip 315-5361 ( sprite generator ) or the srams connected to it ( IC21 and 22)

Since all the address line were good, I proceeded to desolder and test the srams which were infact bad bad.

 

Game was fixed totally

 

Asterix repair log #2

 PCB Repair Logs  Comments Off on Asterix repair log #2
Dec 202019
 

A fresh box of broken boards from Muddymusic arrived recently and Asterix was the first one I pulled out.
Here is the picture I was sent of what it does on boot up

That’s reporting a couple of bad RAM chips but when I did the visual inspection I saw what looks to me like some reflow work has been done in the past and been done badly too. Excess solder and a couple of lifted traces. There were also some bent pins.

I straightened out the best I could and patch a couple of traces too.
The game now passes it POST but I get this in game

At first glance this looks OK and I initially missed it until I ran the MASKROM check from the test menu and it reported a failure at 7K (no picture of this, sorry). If you look at the “ASTERIX” logo there are a few issues around the outline with blue parts.
Going back over those customs and checking all the pins individually I found one pin that needed reflowing. Doing this fixed all the issues.

 Posted by at 9:23 am

BINman update

 General  Comments Off on BINman update
Nov 082019
 

Updated BINman to support IPS patching (v4.6.0).
Recently needed to patch a file so though i best add it. Its not thoroughly tested but im sure bugs will be discovered in time and i will fix it.

 Posted by at 5:18 pm

Ninja Spirit repair log

 Repair Logs  Comments Off on Ninja Spirit repair log
Oct 262019
 

I have a ninja spirit on my collection since more than 10 years. I play it regularly but the other day it once powered up the foreground layer had some vertical black bars crossing the screen for the complete height on the right side.

After a while also the left part started to blick glitching ( cannot be seen on the screenshot below unfortunately)

The board is an irem M72 and the background and foreground layers are handled on the bottom board. The circuit for both playfields is completely the same.

Schematics are available for Rtype which is the same hardware minus the C board.

I checked immediately the circuit which draws the foreground and decided to check a couple of TTL

With some luck I immediately found one 74ls283@10A (IC 78) which was glitching badly the left part of the screen  when testing with the probe on pin 10.

74LS86@7B ( IC50)was also glitching the screen when testing with the probe on pin 6

The HP logic comparator gave me bad outputs on some pins of these TTLs.

After desoldering them I tested on my TTL tester and they were declared good!

I decided to solder back  new ones to be on the safe side and to my surprise the game was fixed.

Turns out that the TTL tester didn’t catch the subtle faults of these ICs ( not Fujitsu parts!)