I thought this repair was the perfect opportunity to show you how to correctly servicing the ‘infamous’ Konami ‘054986A’ custom audio module (obviously this is valid also for the ‘054544’ one).Follow this guide at your own risk.I’m not responsible for any kind of damage!

Let’s start.

I got from my friend ‘supermik’ this Mystic Warriors PCB:

Board played fine but had an orrible sound output, very loud and distorted:

Obviously the culprit was the ‘054986A’ module whose capacitors were replaced by thru-hole electrolityc ones:

But this was not enough to fix the issue.So, instead of troubleshooting the module (the 4558 OP-AMP and the AD1868R DAC undersneath were most likely bad), I opted for its complete replacement using a Premiere Soccer as donor board :

The removal of a module consists in the following steps:

Prepare the board by covering the solderside with some aluminium foil leaving exposed only the pins of the module:

Clamp an IC extractor on the sides of module:

Put the board wrapped in a cloth or pillow  between your legs:

Now, with an hot air rework station do a first preheating of a couple of minutes on the exposed solderside setting the temperature at 100 Celsius degrees.Then, set the station at 250 degrees for a minute or less:

In both cases, you have to move the hot air gun back and forth without stopping otherwise you could damage the board.

After done this preheating (needed to facilitate the solder melting and avoid heat stress) you have to use an heat gun for the last pass.Personally I use a 2000Watt model and set the temp to position ‘8’:

Keep moving the gun back and forth and at same time gently pull the IC extractor:

When the solder will arrive at the melting point, the module will come out easily from its seat:

Next step is the sockets installation, use 1.78mm pitch ones (cutting a single socket in half):

Lastly, mount your good module and you are set.

Ah, I forgot..board 100 fixed!

I got on the bench this Raiga – Strato Fighter PCB for a repair:

Game is a horizontal side-scrolling space shooter developed by Tecmo in 1991.Two were the issues I got when I powered it up.Sound was completely missing ( I got only some samples played randomly) and there were missing vertical lines all over the screen like a sort of scanlines effect:

All video related circuitry is located on he bottom board.Since involved EPROMs and RAMs were socketed I could test them out-of-circuit and they were fine.Then I noticed some dynamic RAMs in form of 12 Sharp LH2464 (64K*4bit) chips.I went to probe them with my oscilloscope and I found weak signals on two data lines of a couple of them (good signal on left, bad on right of the below picture):

So, I removed the two chip and tested into my EPROM programmer where they both failed:

With two good DRAMs fitted, the graphics were completely restored:

So I went to troubleshoot the lack of sound.Main CPU of the audio digital section is a Z80 which commands two YM2203 FM sound synthesis chips for the music and one OKI 6295 for the voice samples.Probing the Z80 revealed random activity/pulsing on all its pins.Besides, chip was wery hot to the touch so I decided to replace it.This was the right move.Board 100% fixed.

 

Got this The Simpson original Konami PCB from my friend ‘supermik’ for a repair:

He told me board didn’t boot showing an error on initial self-test, indeed I got this:

Check reported a bad IC @12 (screen upside down was due this fault) which is, in particular,  a ER5911 EEPROM used to store game settings (you can find datasheet in our section):

I encountered this fault several times and the only option is to replace the IC (probing it confirmed that the only data output was stuck).So I took this EEPROM from a dead board and, after installed it, I performed the initialization procedure that is to hold down the test button while powering on the board and keep it pushed until a message will confirm the successful outcome :

Bart Simpson, eat my shorts! 🙂