Killer Instinct 1 PCB repair

[MickyMac]

I have a killer instinct board that is not booting up fully.

The screen has a few vertical lines of blue that start to fill the screen downwards then it just freezes.

No bong sounds.

On the board I get the HDD LED light solid red, nothing for the sound LED.

CPU pins are all perfect under a microscope and heat sink looks fine.

Here is what I have done so far:

1. Replaced a large 2200uf 16v leaky cap at c63
2. installed a new U98 and CF HDD replacement kit
3. Re-seated all ROM chips. Some pins looked corroded.
4. Pulled and read all roms chips this morning (mame says they are 27C4001 EEPROMs) and all are apparently bad except the new U98 and U34. MAME romident does not recognise the other ones.

Would these bad roms be my problem? The mame source says these are for sound so this may not stop the game from booting up.

Any advice is welcome.

Thank you!

 

[ekorz]

http://solid-orange.com/1758

 

[MickyMac]

Thanks, I was looking at that earlier. The symptoms don't match exactly any of the ones listed on that excellent site but maybe the nearest match is the bad ram diagnosis?

Here is what I am getting at power on:

If it is the RAMs there are 16x 71256 RAMs on this board and they are €6 each on ebay. Can you even test these SMD rams in a chip tester?

 

[nem]

4. Pulled and read all roms chips this morning (mame says they are 27C4001 EEPROMs) and all are apparently bad except the new U98 and U34. MAME romident does not recognise the other ones.

That sounds really weird. But you're right, the eight roms in the corner are just for sound.

 

[ekorz]

View: https://youtu.be/PHx995b6Hrk


usually a solid blue line starts at the top and traverses left to right and then continues left to right down the whole screen. I don’t see any blue line in your video at all, so I’m thinking cpu. The video above shows what the blue line looks like.

 

[MickyMac]

Thanks for the tip. I checked each cpu pin again under a microscope this time nudging each pin with a scalpel. Sure enough a couple at the side facing the HDD in a row were lifted. I reflowed all sides and now I get a solid blue screen like the above video with with some static vertical lines. It scrolls down approx 4/5ths of the way then freezes.

A few of the IC's on the board look like this:

 

[ShootTheCore]

I'd scrub those solder joints clean with IPA & a toothbrush, then touch them up with a soldering iron.

 

[ekorz]

Hear a bong now?

 

[MickyMac]

no bong sadly.

I'll clean up the board and burn new sound ROMs tomorrow.