(Topic ID: 297184)

System 1 Dead Displays - Short?

By MaxAsh

7 days ago



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  • 9 posts
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  • Latest reply 4 hours ago by MaxAsh
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#1 7 days ago

Hey All - Working on a Gottlieb System 1, and I have run into a strange issue. I picked it up not-working (just GI was on). It has a brand new ni-wumpf and a Xpin power supply (previous owner had those installed). I replaced the connector between the MPU/Driver, and now I have it booting / playing, but the Displays are all dead.

* I swapped displays into my System 80 James Bond and they work, so I know the displays themselves are good.

* Note: I don't remove connectors when the game is on, so whenever I mention that, don't worry the game is off!

I removed A2J3 from the Power Supply board and tested the voltages. They all read about what they should:

Repair Guide / My Reading
A2 J3 pin 1 = 60 vdc / 62.1 VDC
A2 J3 pin 3 = 42 vdc / 43.9 VDC
A2 J3 pin 5 = Ground (common)
A2 J3 pin 7 = 4 vdc / 3.89 VDC
A2 J3 pin 8 = 8 vdc / 8.0 VDC

Now, I plug A2J3 in, power up, and take a reading from the back of the connector (as well as the wire destinations on the displays, etc.) Nothing. The 60 and 42 vdc are simply gone. The reference voltages (8vdc/4vdc) are still there. For some reason, whenever I plug in the connector, the voltages disappear.

I checked, and when the connector is plugged in, I read a short between 60 VDC (white/blue wire) and Ground (black). This is true even when all the displays are disconnected. If I unplug A2J3, no short between 60VDC and Ground. If I plug it in, short.

I'm a little stumped here. I checked the fuse in the cabinet and found that it was the wrong rating, which I know is bad. It was 1-1/4 Slow Blow, should be 1/4 Slow Blow. I swapped it out, put everything back together (but only hooked up one display I know works fine) and it immediately blew the fuse.

I have (1) 1/4A fuse left, so I want to try and figure this out before popping that in there (ordering more).

Anyone have thoughts as to what might be going on? I'm puzzled as to how I could read a short only when the connector is plugged in, when all the voltages read fine on the header for that connector with the connector off. Even if I check the wires on the Display end, they show continuity/short whenever I plug A2J3 connector in at the power supply, and no short when I remove it.

#2 7 days ago

More testing today, here's where I'm at. Please note that I unfortunately do not have the schematic currently, so anyone that has it and could provide direction would be great.

On the back of the display board, there are a couple of junction boards for incoming/outgoing wires. The High voltage ground (black) comes into these boards, and gets distributed individually to each display. The same is true of the 60 VDC (white/blue). Including a picture from when I started to de-solder the black wires. The second junction board is not shown (that's where the white/blue 60vdc goes).

I disconnected all of the Ground wires from the board and tested them. There are 7 Wires. I thought I would have 6 wires: (1) incoming from power supply high voltage ground and (5) going to the displays (Players 1-4, Credit). Finding 7 surprised me.

With the game off, I connected each wire individually back to the power supply Ground (A2J3 pin 5). I kept my meter on diode/continuity setting and had it connected to A2J3 pin 1 and A2J3 pin 5.

- All of the display Ground wires, when jumpered back to the power supply, caused no issue. The 7th wire (which doesn't go to any of the displays) immediately causes a short when jumpered back.

- Upon further testing, this 7th wire is actually normal Ground for the game. It goes to all the other grounds in the game, the MPU, the cabinet ground, etc.

So, from what I'm seeing, it looks like the general Ground is connected to the High Voltage Ground at the junction board. Is that normal? It looks like it's always been that way, the wires I desoldered looked to be original, and untouched.

* I connected one display while the 7th Ground wire was removed from the mix and there was 62vdc at the display finally... but it still didn't come on (again, I tested it in my System 80 and know it's good)

*** EDIT: The extra black wire goes back to the MPU at A1J3 pin 4

Cleopatra_Sys1_WireJunc (resized).jpg

#3 7 days ago

I have the schematics in hand now, and looking at a snippet here it appears that the Grounds from A1J3 and A2J3 do indeed connect together.

So the question is, why does introducing the standard ground from A1J3 into the mix cause the voltage to disappear, and the 60vdc/Ground to show as shorted together? If I remove it, I have 60vdc at the displays, if I add it back in, the voltage disappears.

Sys1_Cleopatra_GndDisplay (resized).jpg
#4 6 days ago

Hi Max,

It seems to me that there would have to be a short in the harness if you still it with all displays unplugged. This is because the 60v doesn’t go to the cpu board, so it can’t cause that short. Maybe someone did some repinning before you and made an error?

Dave

#5 6 days ago

I just decided to backtrack towards the beginning and look at the XPin power supply. I know it's an older model (no fuses like the newer Sys 1 models they sell).

* With everything unplugged from the power supply board, I continuity tested A2J3 pin 1 and the GND on the power supply board. I showed continuity, which seemed odd to me. I flipped the board over, and yep, Pin 1 of that header is part of the ground plane.

* So I hooked only incoming power back up to the supply and tested ... +62vdc if I test Pin 1 (red lead) and Pin 5 (black lead)

* BUT because Pin 1 and board GND are connected together on the board, if I move my lead from Pin 1 to the board GND I get 62vdc as well. What the heck? Am I missing something? That seems wrong?

XPIN_psu_back (resized).jpgXPIN_psu (resized).jpg
#6 6 days ago
Quoted from dgAmpGuy:

Hi Max,
It seems to me that there would have to be a short in the harness if you still it with all displays unplugged. This is because the 60v doesn’t go to the cpu board, so it can’t cause that short. Maybe someone did some repinning before you and made an error?
Dave

dgAmpGuy Hey Dave - thanks for the reply! Someone definitely messed around with this game over time, but a lot of the connectors look original and untouched. You never know though. Check out my most recent post above, does that seem strange to you?

#7 6 days ago

UPDATE: After noticing the above, I reached out to XPin. I received an immediate response (great customer service) and they told me to send along some pics of the board. Apparently this model was recalled, but some slipped through the cracks and were sold. This is one of those, sadly.

In an awesome customer service move, they are sending out a replacement free of charge. Now my only concern is: did this defective power supply take out parts of the MPU?

#8 6 days ago

Tough to tell until you get the new power supply. Since it was shutting down voltages, that probably saved you. Just do the same step by step testing when you get the new supply.

I recently joined the system 1 club with a joker poker and had to repair part of the 60v supply, so I learned a lot about how they worked.

Dave

1 week later
#9 4 hours ago

Circling back with an update/closure on this topic.

First off, BIG thank you to the Customer Support at X-PIN. Not only did I receive an immediate reply to my question/issue, within a few minutes they identified my power supply board as a defective/recalled board that slipped through the cracks, and immediately set to work getting me a new one sent out. It arrived quickly, and was an easy install.

The games boots and plays great, and the displays (aside from one) are all working great now. The single dead display was killed during testing with the defective power supply, but to be fair that was because I was trying to make it work, and likely fried something on it. Sourcing a replacement now.

** Just so everyone has the info, the recalled/defective X-pin System 1 Power supply was labeled: XP-GTLB-SYS1 Rev C . ** A picture of the board is attached to this thread. If you have that board, or purchase one that looks like it, do not use it and reach out to X-pin Support!

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