Repair Log Killer Instinct 2 Prototype Board

hyperneogeo

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So about 10 months ago I sent my KI2 Proto board to Chad hoping it could be fixed, unfortunately a few days ago he sent it back with the bad news that it was "not repairable".

The problem was the pcb would start up on a solid grey screen and stay there. The 79R4600 chip was reflowed perfectly, however it would still give the same grey screen.

I didn't want to give up on this board as...well, it's a prototype board!

So I started probing around the 79R4600 chip and noticed it was doing jack crap. IE no activity was coming out of it at all...NOTHING! I compared it to a working KI board on boot and there was activity out of that one. I remembered back to when I got the board and recalled there was no heat sink on the chip, so could the chip be fried?

I took the chance and replaced the 79R4600 chip off a good board (with sound problems) and booted it up. Success! I got a rolling blue screen, however it would always finish with a red screen, meaning a bad HDD. So I changed the HDD with a compact flash and a IDE any boot and still got the same thing. No matter what I did, I would get the same result..so I was like wtf?

I thought, well I might as well try changing the ram as that was the last thing I could try and SUCCESS! It worked and I now have a fully working game.

The difference between a normal KI board and a Proto board is the ram is socketed exactly like regular computer ram sims, so it is very easy to change as shown below.

https://www.dropbox.com/s/djg8alucz7th6q8/20170210_161657.jpg?raw=1

So mental note, grey screen = bad processor, and red screen can mean bad ram on a prototype board...noted!
 
Hello, wish I could have saved all the KI boards that came in.
I did manage to bring back 5 of the 7 Ki board sets though!
Awesome stuff you have a great skill there not many people can solder in CPU's with such a fine pitch like that. I did reflow yours before I sent back and had to finally pass on the repair. I wish I would have had more time to dive deep into it. I had spent about a week on Ki repairs and needed to get back to the normal monitor repairs that I am overwhelmed with. Will keep KI on the repair roster as I certainly got comfortable and confident with them when I did the 7 in a row.
 
Hello, wish I could have saved all the KI boards that came in.
I did manage to bring back 5 of the 7 Ki board sets though!
Awesome stuff you have a great skill there not many people can solder in CPU's with such a fine pitch like that. I did reflow yours before I sent back and had to finally pass on the repair. I wish I would have had more time to dive deep into it. I had spent about a week on Ki repairs and needed to get back to the normal monitor repairs that I am overwhelmed with. Will keep KI on the repair roster as I certainly got comfortable and confident with them when I did the 7 in a row.

Yeah, unfortunately these are a real pain in the butt to work with. It's cool that you are getting better at doing it though as not many people work with these...hell most of the time when I get one of these in, I want to toss it like a Frisbee lol.
 
after the surface mount job I did on a Blitz 99, KI will seem like a walk in the park to do now.

I have a friend that runs an arcade nearby that bought a KI2 and didn't notice there were exposed/cut wires on the power supply and I guess touched them together the wrong way .. now the board BONGs but is stuck on a black screen. I don't know if that CPU crapped out or what, the board is still intelligent enough to know whether a hard drive is connected or not though.

it also owes to how thorough I am with new games that come in. lots of people think I'm overkill and crazy -- apparently I do the right thing, cause that exposed wiring thing would never happen on my watch.
 
after the surface mount job I did on a Blitz 99, KI will seem like a walk in the park to do now.

I have a friend that runs an arcade nearby that bought a KI2 and didn't notice there were exposed/cut wires on the power supply and I guess touched them together the wrong way .. now the board BONGs but is stuck on a black screen. I don't know if that CPU crapped out or what, the board is still intelligent enough to know whether a hard drive is connected or not though.

it also owes to how thorough I am with new games that come in. lots of people think I'm overkill and crazy -- apparently I do the right thing, cause that exposed wiring thing would never happen on my watch.

Sounds like a bad cpu. On mine it was on a solid grey screen no matter what,but it would bong as well.
 
Sounds like a bad cpu. On mine it was on a solid grey screen no matter what,but it would bong as well.

yeah, the DCS hardware is another piece that will make that tone when power is applied.

I'm guessing the disk controller chip (the one that's different between KI and KI2) is what gives the thumbs up when the drive is plugged in or not. :p

I can't tell for certain what's wrong with it. they apparently don't care, so neither do I. maybe one day these arcade ops will realize the importance of actually inspecting their games before tossing them on the floor.
 
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