TZ is haunted

Durzel

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Ok, so my TZ seems to be schizophrenic at the moment.

I moved it from where it was sitting earlier on, where it was working fine, lifted it with my hydraulic table, moved it and put it back down again gently. Turned it on and it went crazy.

Clock kept going around
“Gnd Short Row 1 is Stuck Closed”

Turned it off and back on a couple of times and got a variety of bad results, including:

All three Gumball flashers locked on
Check switch errors for virtually everything.
Auto kicker and/or gumball VUK (?) coils firing repeatedly
Clock not moving
Coin door buttons not doing anything

I removed all of the connectors at the bottom of the MPU, and put them back in. When I booted it next it was behaving normally (clock ended on 12), but all the “check switch” errors remained.

As far as I can make out almost every switch had thrown an error. It seems the test report only tells you about a few of them (6?), so every time I manually activated a switch to clear the errors there would be another 6 showing on the test report.

At this point the Switch Levels (or is it Edge) looked normal, but the game still wanted me to activate every switch to get rid of the error.

After I did this I played a few games and everything worked as normal.

Clearly something isn’t right though. When my GI wasn’t dimming one of the things that was suggested to me was to press down on the ASIC edges. When I did this TZ went crazy then too, and I “fixed” it by tapping on the ASIC - it magically went back to normal.

It seems like something on my MPU isn’t right, but what? The batteries have been off the board for 3+ years incidentally.
 
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Durzel

Durzel

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Durzel

Durzel

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Perhaps battery leakage prior to batteries being removed ...any sign ?

Worth a read also if you havent already
https://www.pinballinfo.com/communi...please-gnd-short-row-1-is-stuck-closed.39701/
Thanks.

The GND short error went away as quickly as it appeared, without me really doing anything.

I managed to fix all the errors by unplugging the connectors at the bottom of the MPU and plugging them back in again, and tapping the ASIC (though I don’t know if that helped or not). I didn’t even lift the playfield which makes me think it’s not a wiring problem underneath.
 

myPinballs

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May be worth removing and reseating the asic in the socket to see if its just a bad connection from years of sitting in the same place. Worth a try first before the long job of replacing the socket or getting a new asic. If you want help with reseating it, or replacing the socket let me know.
 
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Durzel

Durzel

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Think I'd be far too scared to try doing it myself to be honest, and I don't have a puller.

It seems intuitively that the ASIC and/or the socket is likely to be the problem, simply because the errors seemed to be completely random. I don't think I used much force when I pushed down on each edge of the ASIC when I was trying to diagnose the GI issue. Certainly didn't hear anything crack or anything like that. The ASIC didn't look like it wasn't seated properly to begin with though, but I did what was suggested simply to rule it out as the cause of GI dimming problems.

Having said that, clearly something changed because now its gone a bit flakey. As said all I did yesterday was lift it from where it was currently positioned, moved and it and lowered it back down again, and the lift i've got lets you lower very gently, so it was lowered to the ground on the legs with no shock whatsoever.


IMG_3501.jpeg

I'll get some more photos of the MPU tonight, to see if there is anything obvious that jumps out.

Worked ok when I sold it !!
No issues there mate, it was and is still today a minter :) Things go wrong after a while - it's pinball :)
 

PBrookfield

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Just get a puller, my man - PLCC pullers are much more positive and reassuringly solid / easy / safe to use for removal on those kinds of sockets, than those dreadful cursed things they sell for DIP socket chip removal. They can be had for a few quid. The fingers go in the only two sets of slots they'll fit in, and you just squeeze and pull it out. That alone will probably be enough to scrape off the corrosion that would happen in situ, but once out you can also spot hairline cracks, give things a proper clean, scrape.

I bet dollars to donuts that pulling the chip, cleaning all metal pins on socket and chip and replacing will banish these gremlins back to the Zone.
 
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myPinballs

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Just get a puller, my man - PLCC pullers are much more positive and reassuringly solid / easy / safe to use for removal on those kinds of sockets, than those dreadful cursed things they sell for DIP socket chip removal. They can be had for a few quid. The fingers go in the only two sets of slots they'll fit in, and you just squeeze and pull it out. That alone will probably be enough to scrape off the corrosion that would happen in situ, but once out you can also spot hairline cracks, give things a proper clean, scrape.

I bet dollars to donuts that pulling the chip, cleaning all metal pins on socket and chip and replacing will banish these gremlins back to the Zone.

I really dont agree here. Telling someone to 'get a chip puller & pull the asic' if they have never done this before and aren't familiar with repairing boards is just asking for trouble. Changing a transistor is one thing with some practice but removing an asic is something else... Most likely the problem will just be made worse and more difficult for someone who does it all the time to repair or the board damaged beyond repair. From the picture the socket doesnt look corroded so a remove and reseat may solve it, or the asic itself may just be worn out.

Anyway my advice to the op is send to me, pinball heaven or pinball mania (choices) and let whoever reseat the ic and test in another game, before the issue is made worse and you end up buying a new board. my 2p
 

PBrookfield

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Changing a transistor is one thing with some practice but removing an asic is something else...
You reckon a transistor change with soldering iron is easier than removing an IC using an PLCC puller [for a beginner]...? That hasn't been my experience at all, but I will readily concede that you have more experience than me, and absolutely would do with the Williams ASIC in particular.
 
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Durzel

Durzel

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To make it easier - I wouldn't attempt a transistor change either. I am not comfortable doing board work, particularly on boards that are as valuable as these are. :(

Thanks for the help all.

Dumb question - at what point would you lose your high scores from pulling an MPU board? I realise that if I also pull out the remote battery pack (i.e. leaving it all connected up) that it will keep scores until something else is done, but I'm curious as to whether this process is likely to leave me with a factory reset TZ . Not a deal breaker obviously.

EDIT: For what it's worth - I'm pretty sure the LEDs on the MPU were normal while this was all happening. It wasn't like it failed to boot, it was just completely incoherent.
 
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myPinballs

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To make it easier - I wouldn't attempt a transistor change either. I am not comfortable doing board work, particularly on boards that are as valuable as these are. :(

Thanks for the help all.

Dumb question - at what point would you lose your high scores from pulling an MPU board? I realise that if I also pull out the remote battery pack that it will keep scores until something else is done, but I'm curious as to whether this process is likely to leave me with a factory reset TZ . Not a deal breaker obviously.

EDIT: For what it's worth - I'm pretty sure the LEDs on the MPU were normal while this was all happening. It wasn't like it failed to boot, it was just completely incoherent.

Assume a board that is sent for repair will be returned with factory defaults, so all settings and high scores will be lost. Boards are tested in other games when repaired to check functionality so different roms will be put in and this clears any saved data regardless.
 
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Durzel

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Well, this has got a bit of an embarrassing conclusion..

Was playing a game and midway through the game the gumball and upper right flipper flashers stopped working. Turned game off and back on again. Game powered on with all the gumball flashers locked on - like it did before, and the upper right flipper flasher on, a coil firing somewhere and the clock not working...

Powered off game, tapped on ASIC, no difference... ugh

I then noticed that the long ribbon cable that connects the MPU to the extra flasher board was not on properly on one end at the MPU end. It was on, but not pushed down on one end. Pushed it down and everything was back to normal..

Think this was the problem all along.. why does a wonky ribbon cable cause so much chaos? Surely flashers should fail off instead of on?

Anyway at least it looks like my MPU is fine.
 
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PBrookfield

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Well, this has got a bit of an embarrassing conclusion..

Was playing a game and midway through the game the gumball and upper right flipper flashers stopped working. Turned game off and back on again. Game powered on with all the gumball flashers locked on - like it did before, and the upper right flipper flasher on, a coil firing somewhere and the clock not working...

Powered off game, tapped on ASIC, no difference... ugh

I then noticed that the long ribbon cable that connects the MPU to the extra flasher board was not on properly on one end at the MPU end. It was on, but not pushed down on one end. Pushed it down and everything was back to normal..

Think this was the problem all along.. why does a wonky ribbon cable cause so much chaos? Surely flashers should fail off instead of on?

Anyway at least it looks like my MPU is fine.
Haha. At least you sorted it.

why does a wonky ribbon cable cause so much chaos? Surely flashers should fail off instead of on?
Try connecting the ribbon cable off by one row (that is, one row of pins overhanging, connected to nothing.)
Turn on the machine.
All of the coils will lock on immediately, and hard. In less than a second you'll blow fuses.

Remember, sometimes pins go _low_ to signal, instead of going high. And when circuits are floating, all bets are off and it becomes circuit-specific as to what happens.
 
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Durzel

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It’s annoying for sure. Me tapping on ASIC must’ve vibrated the connection enough to make contact briefly, then a vibration from playing the game would screw it up again.

It didn’t look wrong from above, it was only when I was looking at the extra board at the top right of the backbox and following the ribbon cable back that I noticed it.

This is the board that was badly connected. I guess it does more than just flashers.

7339CC89-B9A7-4F20-9511-F6CD2D39E771.jpeg
 
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Durzel

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Ok I’ve got another ghost in the machine :)

Was going to remove the mini playfield today to begin my project to change the switches, thought I’d take photos of everything first so I have a frame of reference, and saw this...


All the switches on row 6 work when tested manually (don’t know how to test “Clock Hour” though, but the clock works fine), and I haven’t noticed any issues or strange behaviour during gameplay, and there’s no errors reported on boot.

I lifted the PF and put it back down again, changing nothing, and it went away with no phantom switch activations for over 5 minutes. Went to close the coin door and it came back again? Could be totally coincidental - row 6 seems to have nothing to do with the coin door.

Any thoughts? A ground short would make the whole row pulse wouldn’t it?

I haven’t tried reseating J206 or anything yet, just thought I’d ask first in case there was an obvious fix.
 

Dex-Jay

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It looks knackered. I will however take that TZ off you for a fee. I await your delivery. Free delivery I hope.
 
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PBrookfield

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Ok I’ve got another ghost in the machine :)

Was going to remove the mini playfield today to begin my project to change the switches, thought I’d take photos of everything first so I have a frame of reference, and saw this...


All the switches on row 6 work when tested manually (don’t know how to test “Clock Hour” though, but the clock works fine), and I haven’t noticed any issues or strange behaviour during gameplay, and there’s no errors reported on boot.

I lifted the PF and put it back down again, changing nothing, and it went away with no phantom switch activations for over 5 minutes. Went to close the coin door and it came back again? Could be totally coincidental - row 6 seems to have nothing to do with the coin door.

Any thoughts? A ground short would make the whole row pulse wouldn’t it?

I haven’t tried reseating J206 or anything yet, just thought I’d ask first in case there was an obvious fix.
Definitely a whole row dropping out. It's not shorting to ground as that would trigger them all, but they instead seem to be losing ground. Or, the switch matrix row connection is marginal / corroded.

You replaced that ribbon cable yet? ;) This is still within the sphere of influence for ribbon cables... especially when we know that they were already flaking out.

If you have already then you need to think about the possibility that you've got corrosion issues on the MPU. I can see in one of your earlier photos that your batteries were moved off-board but there's some clouding that's tell-tale of old acid damage. The stuff is insidious and could even be, just maybe, what is making your IDC connector or even the ribbon a flaky. Of course IDC ribbons don't actually need an excuse to fail... but still.
 
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Durzel

Durzel

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Not replaced the ribbon, no. I'll remove and replace J205 tonight and see if it makes any difference. Will give the pins a rub with a fibreglass pen too. It is very bizarre though, and as you say the haunted nature of it does point towards the MPU.

It hasn't spazzed out like it did before since I properly seated the long ribbon going from the MPU to the 8 driver board, and to be honest I wouldn't have even noticed this problem if I hadn't been taking photos in advance of removing the mini playfield.
 

PBrookfield

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Which ribbon are we on about replacing, all of them or the long one?
Well, to be blunt - any that have given you problems, as a minimum.
But let's take a step back, first - can you catch those switch matrix issues happening if you keep the ribbon cable between MPU and the Power driver board completely removed? The very short, horizontally aligned one to the biggest board in there.

The game isn't going to be playable like this but it's diagnostically relevant. If you can trigger the switch spaz-outs without that cable in situ, then you either have a playfield wiring problem, or you have corrosion/other faults on the MPU.

We're going at this problem completely backwards with this, by the way - I'm only suggesting this because we *know* the ribbon cable is already duff. I suggest this just to eliminate possibilities.

And of course, be careful putting that cable back in place - refer to my earlier post where I mention what happens if you insert it incorrectly
 
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Durzel

Durzel

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:)

I'll have a look tonight. It is very intermittent. As said when I lifted the PF and put it back down again it didn't do it for about about 10 minutes.

I assume if I boot the pin with the MPU to PDB ribbon disconnected it's going to have a bit of a fit isn't it?

EDIT: You said "we know the ribbon cable is already duff".. I'm not sure what you mean here? The original issue I had at the start of the thread was due to the long ribbon cable being off slightly, as in not fully pushed down on one end. Once I did that the problem went away and hasn't come back since.
 
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PBrookfield

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EDIT: You said "we know the ribbon cable is already duff".. I'm not sure what you mean here? The original issue I had at the start of the thread was due to the long ribbon cable being off slightly, as in not fully pushed down on one end. Once I did that the problem went away and hasn't come back since.
I may be getting carried away in that case - I'm very prone to doing that, by the way, so I apologise in advance. In this very thread I suggested you pull the ASIC out just to have a look, after all. I'm that sort of stubborn fault-chaser. I forget that I'm a bit mental gung-ho sometimes and am usually happy to break things as long as I learn something 😰

Anyway, my reasoning was that the sporadic issue you're seeing has a chance of being related to a ribbon cable (though it's usually corrosion on the MPU to be honest - not always of course) so there is a possibility that your ribbon cable was mis-seated and is also corroded/worn - hence 'not really fixed yet.' And 'temporary' fixes for corrosion on electrical contacts can seem anything but temporary sometimes - just think of all the nonsense we all came up with regarding blowing on NES cartridges and suchlike. We were convinced it worked but it was mostly all ********. The only trick that sort of worked was pencil rubbers on the contacts - removing oxidation poorly but better than adding moisture to bare metal would do. And the reasoning I heard of 'adding grip to the contacts'... kids are daft.


That being said - sensible cap on - honestly if it's really not giving you many problems, and it really has shut up with problems for a while since you reseated the cable - leave it alone until it actually does something disruptive, consistently, and not just when you're partially dismantling it.

Don't bother with the ribbon cable removal test. I'll look at suggesting a more precise and safer diagnostic test after I get home...
 
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I removed all the connectors and cleaned the pins with a fibreglass pen and isopropyl on a cotton bud.

Powered it on and left it on Switch Edge for a while (10 mins or so?) and nothing happened. Don’t know if that’s fixed it since it didn’t do it for about the same time before? Maybe it’s just the Twilight Zone...

102188CB-A90F-49A3-8716-CA3F908941A4.jpeg659ADCDD-C2AA-486A-9150-FD648EC6ACD8.jpeg466878A8-04D9-458F-9CD4-7DC39C16605E.jpeg34708240-757D-4589-A1A3-B6BEF4C0723A.jpeg348F55BA-9F5B-4A6F-AE73-290FB8EC2120.jpeg

I noticed one of the pins on J208 is bent slightly, but it seems to go in the connector ok?

And the most boring video ever:

 
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