TOTAN blowing CPU board chips

(Topic ID: 201237)

TOTAN blowing CPU board chips


By TheLoungeKing

1 year ago



Topic Stats

  • 10 posts
  • 4 Pinsiders participating
  • Latest reply 1 year ago by mschonbrun
  • No one calls this topic a favorite

You

Linked Games

#1 1 year ago

I have been trying unsuccessfully to get our TOTAN running again for the last 6 months. The problems started with switch matrix shorts. I replaced U20 and things were resolved for a short period (maybe a few games, I don't remember, it was months ago).
Then more switch matrix problems. Checked the play field and couldn't find any wires touching where they shouldn't. Had to replace U20 and U23 to get it working again. And it again worked for a short while and broke again. This time G10 error. I found a small amount of green on one of the battery holders so I just bought a Rottendog CPU board and replaced the board. Still had the G10 error, so bought a shifted bits G10 chip. That resolved the error and we were able to get about an hour of play time before another reset and G10 error.
At this point what is the best course of action? Inspect all the coil wires from the playfield to the backbox?
If it's any sort of clue, the last couple times the game reset it was within a second or two of shooting the ball which seems like maybe more than a coincidence. But the first time it reset (6 months ago) I'm pretty sure the ball was in play,in the top left.
Any help appreciated.

#2 1 year ago

I think the approach that I would take is to rule out the playfield by disconnecting any and all of the playfield connectors to the CPU and allowing the game to be powered on for enough time that an issue would have occurred previously. If you do not get a new issue, then you have narrowed down the search window. The CPU chips usually don't have issues like this unless you have voltage being applied to the switch matrix. The other thing you could do is take the switch matrix connectors and go and look for voltage on the pins. I don't recall what voltage the switch matrix runs at, but you're looking for something that's out of whack, and in the coil voltage range (18-50 VDC).

Good luck -- interesting problem.

Marc

#3 1 year ago

agree with Marc, what I would do is get a volt meter, and with the switch matrix connects off, and game on, look for any voltage on the disconnected switch wires. Very much sounds like you have a switch making contact with some other power source, could be a GI light or a coil.
The switch matrix runs off 5 volts which comes from the mpu.

#4 1 year ago
Quoted from wdennie:

The switch matrix runs off 5 volts which comes from the mpu.

Thank you so much for confirming that. I thought it was 5, but didn't want to give bad forum advice

#5 1 year ago

Thanks for the responses. I can't believe no one's created a module, with fuses or opto-isolators, that you plug in between the ribbon cables and the CPU board to diagnose/protect from high voltage issues.

#6 1 year ago
Quoted from TheLoungeKing:

Thanks for the responses. I can't believe no one's created a module, with fuses or opto-isolators, that you plug in between the ribbon cables and the CPU board to diagnose/protect from high voltage issues.

It would be a lot of work for an issue that's really not all that common (and it's certainly a good idea). Maybe you can make one—most pinball tools are passion projects.

#7 1 year ago

I'm thinking about it. It's been 20 years since my TTL class and it's totally not coming back to me.

#8 1 year ago

Hmm, these are cheap enough that maybe I'll get a bunch of them and try inserting them between the connectors.
amazon.com link »

#9 1 year ago
Quoted from wdennie:

... The switch matrix runs off 5 volts which comes from the mpu.

Quoted from pintechev:

Thank you so much for confirming that. I thought it was 5, but didn't want to give bad forum advice

NO !
The logic on the CPU board is indeed 5 volts powered : the Security Chip and the output latch (U23) are TTL. But this command an ULN2803 driver, that switch ground signal. There is then pull-up resistor connected to +12 volts. So there is either ground (active strobe) or +12v (inactive strobe) on the matrix switches.

On input, a diode filter only grounded signals - and there is LM339 comparators using again pull-up resistors to +12 and this voltage as reference. Note that, by this way, the pulluped 12 volts goes also to the matrix through the diode (when no switch establish connection to ground strobe).

Sending a high voltage on the matrix will usually not burn the input stage. As a diode protect the LM339 (U18/U19) inputs. But it can burn the output stage, as the ULN2803 (U20) may drive at the same time, a ground signal.

#10 1 year ago

Thank you for the correction

So, look for anything much higher than 12v on those pins.

Promoted items from the Pinside Marketplace
$ 69.95
Cabinet - Shooter Rods
Super Skill Shot Shop
$ 53.00
Playfield - Toys/Add-ons
Lermods
From: $ 42.00
Cabinet - Shooter Rods
ModFather Pinball Mods
$ 129.00
Lighting - Led
LED OCD
$ 15.00
€ 95.00
Lighting - Led
FlipperLED
€ 40.00
$ 40.00
Lighting - Other
Rock Custom Pinball
From: $ 16.95
$ 999.00
Flipper Parts
Mircoplayfields
From: $ 799.00
Hardware
CPR Playfields
8,250 (Firm)
Machine - For Sale
Oklahoma City, OK
$ 35.00
Electronics
Ewe22 Security PIC Chips
From: $ 9.99
From: $ 369.95
Boards
PinSound
$ 4.99
Playfield - Plastics
ULEKstore
$ 35.99
Lighting - Interactive
Lee's Parts
8,000 (OBO)
Machine - For Sale
Oxnard, CA
From: $ 22.00
From: $ 9.99
From: $ 29.00
Boards
KAHR.US Circuits
$ 115.00
Cabinet Parts
Merf's Pins
Great pinball charity
Pinball Edu

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside