T2 game boots and starts up. Everything looks fine. Start button isn't starting the game.

The game was playing fine then I went to play another game and the start button would not start.

It tests out and works properly and even is detected in the switch edge test.
I unplugged all the cabinet switches and re-booted. In the test report i'm still getting a Row 2 grd short. The whole row is lit up in the matrix.
This locates the problem to within the MPU and not the cabinet switches.

My next issue is what to do next. Based on the schematics I decided that switching out U18 was the best place to start as Row 2 goes directly into it. I replaced the IC with LM339, and a socket. Re-installed the board after checking all the traces were still good from the IC back to each component. Booted the machines, and entered the test report and I'm still getting the same Row 2 grd short. Not really sure what to do next. Replace U19 and U20??? I'll post some pics of my progress but any suggestions help would be appreciated. Or should I just invest in a logic probe to diagnose which IC is the issue here?

I'm sorta stuck now at what to do next. I know I could just buy a replacement board, but I'd really like to learn how to solve and fix a problem like this. (My first time doing board work).

Capture (resized).JPG

U18 (resized).JPG

Well I'm not super comfortable but I was able to replace U18 last night. Had a little warm up soldering tutorial on replacing a header on another DE power supply. IC removal is not easy. At elast for me it wasn't. I actually bought that IC as well, so I guess I might as well go ahead and replace it too.

Thanks! I'll give that a try. and yes I still had the short with all the connectors disconnected.

I have lots of experience soldering just not on boards. either way I went at it and replaced U20. I wish I had watched your video first that needle technique looks way easier. Yes I did cut the chip off before. Anyhow long story short, this U20 chip had been replaced before. It already had 3 jumpers on the back. It was in rough shape. I got it out, and only lost 3 more holes in the process. lol

Regardless, I got it back in and into a socket. no way I'd ever not use a socket. I jumped over all the broken traces to there proper spots and then double checked them all with the DMM.. They checked out as should I believe.

Popped the board back into T2 and now my Direct switches don't work. I have nothing on the coin door working. Seems like my start button is now working though as when I press it it responds by saying CREDIT 0. Can't enter the test menu without the error button.

Any idea on where to go next?

Replacement board is about $260 here in Canada. Not the end of the world, but i'm enjoying this challenge of learning electronics and gaining soldering skills.

Thanks for all the help and tips guys.

ps. german-pinball, what was the cleaner you sprayed on the board after? I didn't catch it in the video. The brush thing that you clean up with.

I was told on another site to check U16 pin 3 for 12v as this is provided for the direct switches on the coin door. I'm missing 12V at this pin.
Anybody have a good suggestion on where to jumper 12v to this point from?

I'm definitely trying to learn to read and understand schematics. I took an introductory electronics course back in first year engineer. That was about 15 years ago, and it's mostly a blur but some of it is coming back. Either way I can read basic stuff I think but sometimes things get confusing.

Like for example, how come U20 doesn't show what pin 9 & 10 are connected too? Is it just assumed to be something?

Anyhow I totally hear all you guys on the fragile state of these boards. I learned that first hand. Had to jumper 3 new traces, along with 3 that were already damaged from the last repair. Which LM339 would you suggest jumping the 12v from? Or should I just grab it from the rail where the original trace looks to be going to.

U20 (resized).JPG

Hi guys,

I'll give an update. I will admit I was the problem when testing the pins. I was reading the pins wrong on the IC's. Only realized it when I pulled up the data sheets. I was testing pin 10 of U16, which as it turns out is a ground. U16 pin 3 has now been jumpered over to pin 10 of U20. Success. The direct switches work now. The test report is coming back with no errors.

Okay so the board work was a success, however encountered a new problem. The start button now works, however when pressed the game would say "PINBALL MISSING" and start a ball search. (YES I HAVE 3 BALLS INSTALLED). Anyhow, I went into the switch matrix edge test and the three trough and outhole switches were no longer being detected in the test. Also when I was pressing the Start button, it was showing up in the TEST as the "Right Flipper". Left flipper would not register in the edge test. All other switches seem to be working fine however.
I have noticed that somebody in the past has ran a wire from the outhole switch all the way along the harness up into the backbox and have connected it to J207. I assume this was the wire for the outhole switch.

Not sure what is going on exactly now. but looks like i'm not registering a bunch of switches in the column #1.