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TOM power issues... what is going on here!

R

RigidCollision

Registered
Joined
Mar 11, 2018
Messages
13
Location
Dorset
Hi guys,
This is my first post on the forum. So hello to everyone!
I have TOM that I have been running for 15 years. My greatest pinball purchase!

Today I powered it on and I got a scrambled display, transformer hum, a single *bing!* and then nothing. No lights on the play field or header. No apparent power to the play field at all, no further sound. I think the scrambled display is power related. It's a new colour replacement screen.

Every time I power on it does the same thing as mentioned above.

The machine has not been moved, is in awarm and dry environment etc.

Fuses all seem fine.
TP1 12v is testing at 13v.
TP2 5v is reading a fraction under 5v.
TP3 12v is just under 12v.

I checked J116, J117, J118. Can't see any obvious loose/disconnects, no scorching. No signs of obvious degradation/dirt/corrosion

Tested J606 with its plug connected.
12v unr = 13v
5v = 4.8v
Checked ground was OK.

I am stumped where to go from here.
Any tips would be greatly appreciated.

Kind regards,
 
Sounds like its fubared. I have wine. How much do you want for it?
 
Locate the connector on the power board below the short Grey ribbon cable. Pull it off and put it back on again. See if that does anything.

I suspect your cpu is not running. One of the leds on it should be flashing if it is running. If not then you either have a poor power supply to it or a data problem ( try Reseatting the top two ribbon cables ) , or a cpu fault.

Reseatting that connector often helps with the power problem but won’t cure it for ever.
 
Popped the connector off and reseated it. No obvious problems with it.
Power on does not produce the flashing "I'm alive" LED as expected.

I reseated all my ribbon cables earlier today.
 
Take off the top two ribbon cables from the cpu. See if the cpu boots then. Display and sound won’t work but if one of the cables is dodgy it can cause the cpu not to boot. It will boot with them disconnected.
 
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You haven’t had battery damage on the CPU board? I can’t remember if this is one that susceptible to it.
 
Hi Neil,
The CPU board I have is the one with the battery pack mounted at the bottom of the board. It had battery damage about 8 years ago. My battery holder is on its own board/stand-off.
 

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Do you have another, working, game that you can board-swap and cable-swap with ?

This would help isolate the problem. If you then determine that the cpu board is buggered for example you could mail it to pinball mania for repair.
 
Unfortunately this is currently my only pin. They come and go over time but TOM is a constant. Right now I don't have a spare for doing swapsies.
 
Right, got an answer!
Looks like my CPU board is dead.
The culprit is a battery leak, but it's not what you might think.
The battery on my board is one of those that is mounted on a seperate daughter board at the base of the CPU board so there is no direct battery contact with the CPU board. Any leak should be contained to the daughter board.
There has been a leak at some point in the machines life and the VAPOUR from the leak has nackered the whole back, lower fith of my CPU board. Totally shot! Looks fine from the front.

Now I need a new CPU board!
 
I'm confused about this.. if it had a leak ~8 years ago, and was presumably repaired, why would it manifest now? Are you saying that by using the pin it's warmed up the CPU board and aerosolised the existing corrosion?
 
That's about the long and short of it. Sounds daft I know, but the lower fifth of the board looks like it has ACNE, so unless I am suffering from some sort of 'board rot' the only culprit that even comes close to fitting the frame is alkaline residue on the battery board not having been cleaned off properly and producing fumes. For that I have to put my hand up - maybe I didn't clean it as well as I should have. Lesson learnt.

Anyway the board has been tested and is dead as a dodo. Certainly an uneconomical repair.

Will get a PINLED replacement board.

It's tedious and an expence I didn't want but on a £5k+ machine the cost of a board isn't a major consideration, especially when I have a 120kg floor weight at the moment. :thumbs:
 
Definitely worth giving it a clean with vinegar/isopropyl alcohol first. You'd probably remove the "acne", and if its already considered dead what's the harm?
 
Paul R Owen said:
Is it beyond repair? Can you scrub the "acne" with vinegar?
Click to expand...

Yeah, it's beyond 'reasonable' repair. Vinegar will only nuetralise the leaked alkaline and prevent further damage. One day when I have enough time to completely strip it apart, clean it and resolder everything I might be inclined to try but to be honest by then I will have a new board in there, I will be heading for Grand Finale and wont give it another thought. :)

For now, a new board and a working machine is my priority.
 
Fair dos.. there is always an element of "how much is my time worth" with these things. :) Perhaps worth sending the board off to someone to get repaired, it might turn out to need less work to get working again than it appears, then you'd have a board you could sell on (or a PinLED one if you wanted to swap it back in)
 
Durzel said:
Fair dos.. there is always an element of "how much is my time worth" with these things. :) Perhaps worth sending the board off to someone to get repaired, it might turn out to need less work to get working again than it appears, then you'd have a board you could sell on (or a PinLED one if you wanted to swap it back in)
Click to expand...
I totally agree. The damage has killed the board. It has been tested as 100% dead. The ROT affects that whole bank of components on the lower half, so its going to be a lot of de-soldering and re-soldering to get it sorted. What annoys me more than anything is not having an 'original' machine with original parts when I swap the board.

The main thing now is to have options and get the machine working.
 
Cheers for the links.the 'untested' looks to be a practical option. The other one comes in at around £300 from the US, which is a bit pricey, but then again what price do you put on originality?
 
No probs.. I've spent far too much time at work looking into this, so need to stop now lol :)

ToM uses a board with a part number of A-17651-50039 (you probably know this already). The untested board is A-17651-50038 but I'm guessing the number after A-17651 refers to the different games it was installed in (zooming in reveals it to be "Dirty Harry"). From a cursory Google search you'd need to swap both the EPROM and security chip from your board to this, but I'd double check / ask on here for advice before buying it.

EDIT: Make that A-17651-50036

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Yeah, that sounds about right. The suffix is machine specific.
I have to make sure that the boards death did not kill any of the chips etc!
 
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There's a WCS being parted out, someone is buying the entire boardsets, but might be worth finding out who and if they want to sell that on for a quick win? If not, the seller has a lot of project pins go through him, may want to part out another.
 
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