Hi, thanks for reading!

Just got a TM, was working before it shipped, not now - what it's doing is it will start up, play the "Time Machine" song - just plays the words "Time Machine" and then no more sound, nothing on the displays. All the GI lighting is good.

Looking at the MPU board, looks like one of the PIA 6821s was replaced some time ago, as it was socketed, the others are not. Have replaced that socketed PIA with another, system status hasn't changed. Was going to socket those other PIA chips, but also wanted to look at the power side of things.

The trouble there is I can't read the scanned/photocopied manual on the IPDB site.

Does anyone have notes or a better schematic for the PSU board? What voltage levels should I be reading and where?

Thanks in advance!

I'm getting 4.920 volts on the test point of the MPU board, I'm assuming it's good. Looks like the prior owner used a WMS system 9 PSU board.

Got 'er working ok, but display is borked up. The reason the game wouldn't boot was that SRAM chip - had legs bent under by previous owner.

I got past that part - I'm wondering if I should put up a new thread as there's a new problem - display is scrambled. The two displays at the bottom are more legible, but top two aren't. It's not the display or the PSU, as I have new boards from Rottendog for each. I'm thinking it's something with the PIAs or maybe RAM?

I'll try this tomorrow and see where it gets me. Thanks!

It's probably too much to post a video here, but I'll link one also from my onedrive account.

@pinballmaniac40

IMG_0521 (resized).JPG

IMG_0522 (resized).JPG

IMG_0525 (resized).JPG

https://1drv.ms/f/s!AvCqcjWCTr808SPqi9W1aC079c8p

There's the link for the TM video as well as the pictures (originals).

Update: I got it.

Bad ribbon cable.