1941 : Counter Attack repair log #2

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Dec 092017
 

Got this 1941 : Counter Attack (Japan release) B-BOARD for repair:

Game had some graphics issue on backgrounds:

I swapped the C-BOARD with the one from a Street FIghter II : World Warrior which mounts the same ‘CPS-B-05’ ASIC :

GFX issue disappeared so the fault was in the C-BOARD :

I was asking by owner to transplant the ASIC from the donor C-BOARD to original one, here’s a step-by-step collage:

The operation was successful :

Board 100% fixed and aesthetically like genuine, appearances count too…

 Posted by at 4:47 pm
Dec 072017
 

Received from USA this Pac-Mania ROM board (Namco System 1 hardware) for repair :

According to the owner board played fine but mute, this was confirmed once powered it up.Using my audio probe I could hear sound on the input (pin 2) of the two LA4460 amplifiers but nothing on outputs:

At closer inspection one of them was literally blown up:

So I proceeded to remove both:

and installed two new spares and some thermal compound on heatsink:

Sound restored and board 100% fixed.End of job.

 

Update:

After converting this board to Splatterhouse I found that voices and other sound FXs were missing:

I quickly pinpointed the fault in a bad TL084 OP-AMP, replacing it cured the issue:

 Posted by at 4:22 pm

Defender repair log #2

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Nov 302017
 

After reparing my Defender ( see this log: https://www.jammarcade.net/defender-repair-log/ ) I noticed that the screen had some horizontal lines of different brightness.

At first I didn’t give much attention but then I decided to look at this issue deeper.

Moving the screen left and right with the monitor commands I noticed these defects:

 

 

Having the experience of a similar problem on my Burnin Rubber ( https://www.jammarcade.net/burnin-rubber-repair-log/ ), to me it was clear there was a video blanking problem

With the schematics in hand I found this circuit:

Signals from 7420@5C were good so I started probing the 7400@4B

 

All signals were good except that pin 10 was floating.

Looking at the above mentioned schematics, pin 10 is tied to the nearby pin 11!

I checked the board and found out that actually the pcb has no trace connected the 2 pins togheter!

 

No broken traces, it is actually simply not there!

I connected the two pins and…..

 

Game fixed!

Now I am wondering if my CPU board revision has a production error.

Searching on internet I haven’t found a similar problem therefore I would like to have a feedback from other owners of Defender if their pcbs has the trace or not.

Liquid Kids repair log #2

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Nov 302017
 

Received this Japanese version of Liquid Kids for a repairĀ  running on a different F2 hardware.

 

The game was playing fine but hadn’t any sounds.

Amplifier and preamps were good so I started to probe the sound circuit logic.

The Z80 sound cpu ram had some weak signals

After replacing it , the sound was restored.

Popeye repair log

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Nov 302017
 

Quick repair this one.
Received this board recently from a great eBay seller.

It was sold as faulty and indeed it was. On power up I was greeted with this static screen.

As the Z80 is already socketed on these boards I hooked the Fluke 9010 straight up and did a RAM test. As I was expecting, this failed.

The main RAM is located next to the 4 program ROM’s. One socket and one new RAM chip and we have a nice easy fix.

 Posted by at 8:15 pm