In search of P&M 25CENT DRAW POKER machine information

[Trdstarlet]

Could be I'll give that a try as well. The dc board for the crt has india as country of origin so it could be a coincidence 🤔

[Chris-socal]

DC board for the CRT? What is a DC board?

[Trdstarlet]

There is a broad that has another board that has dc instead of ac current. I'll verify in the morning.

[Chris-socal]

I can’t see much but I can see the board is AC in and DC out…the monitor does not use DC in….it runs on isolated AC 120v.

I now have a new theory. Did someone bypass the low voltage transformer and converted the machine to a Switching DC power supply? It would make sense and many games from the late 80’s are being converted to get rid of the old transformers….it would answer why you have wires coming from the transformer that don’t go anywhere. That is probably the power supply you should be checking. It probably has 5v and 12 volt or something like that….just find the common ground and verify that each voltage header works. Maybe the 5v line pooped out in that and thats why your game doesn’t start.

But again, that monitor runs on isolated 120vAC….maybe that is why they left the big transformer in there because it has an isolated 120v coil for the monitor.

Chris

[Trdstarlet]

Hey Chris, thanks for the reply. Yeah, I’ll be testing the board shortly. Considering the output voltage is 5V, I’m thinking it’s for the game board — which would explain why it’s not booting up if it’s not providing that 5V output. I’ll circle back in a bit, as I just found the spec sheet.

[Chris-socal]

Be very careful with that open, there is high voltage around the big capacitor and it can hold charge after being powered off.
Always discharge the big capacitor if you are going to be handling it, many of them self discharge but some models don’t.
It should put out around 5.1 to 5.2v. Sometimes they start low and ramp up, this becomes more pronounced as the caps age. Easy to check.

Chris

[Trdstarlet]

Yeah, the reading came in low — I got a 1.580 V output. There’s also a high-pitched sound, which leads me to believe the capacitors and/or the shunt voltage regulator IC might be bad.

[Trdstarlet]

Shotgun approach perhaps instead of chasing down  individual capacitors?

[jay]

Switching power supplies are like $25
Swap-tronics

[Trdstarlet]

Do you have a model recommendation in mind?

[jay]

Not really - you just need to find one with the same output voltages and a slightly higher wattage rating that is there now.

If you google JAMMA boards - you will get to arcade sites and there will be power supplies
JAMMA = Japanese Arcade Machine

The original Packman, Galaga, Donkey Kong machines all had JAMMA harnesses that ended in the same edge card connector.
This plugged into a 2 or 3 layered board set that were often as large as 6 x 8 .....
These boards often died a painful death - either TTL logic gave up the ghost or a battery leaked or a soft drink etc.

You can now buy Galaga on a small board and the original harness snaps right on and the old classic is back in business.
In reality it is more common to find a 23 in one  board, 60 in one...  or even 1001 in one  with all of the classic games with people turning these units into a multi-cade.

OR .....

You buy the board, the harness, a power supply, and some buttons and build your own.
Anyways the purpose of the post was to point you to power supplies.

Amazon is also full of them.

[Trdstarlet]

Thanks, Jay, for bearing with me. I’m still deciding whether to go for a full restoration or just get it operational. At this point, I might do both — by installing new components to bypass the old ones for now, while I work on restoring the original board and components.

[jay]

It was my understanding that between yourself and chris-socal that your original power supply appears to be replaced by a switching power supply.... and the latter is somewhat ka-put....
My meandering post was to suggest rather than try and play with individual caps (and the time/patience to do so) on the power supply you simply swap it to another switching power supply as they are low cost.

It would be my conjecture that the reason for the pooched power supply might have been draw and getting one with higher wattage would be a good idea.

The arcade sites and by extension Amazon have switching power supplies enmass.

[Chris-socal]

It was my understanding that between yourself and chris-socal that your original power supply appears to be replaced by a switching power supply.... and the latter is somewhat ka-put....
My meandering post was to suggest rather than try and play with individual caps (and the time/patience to do so) on the power supply you simply swap it to another switching power supply as they are low cost.

 It would be my conjecture that the reason for the pooched power supply might have been draw and getting one with higher wattage would be a good idea.

The arcade sites and by extension Amazon have switching power supplies enmass.

Agreed:
Simply following the wires from the switching PS would tell you very quickly if that is what's powering the board now.
I have worked on a lot of SMPS in attempt to fix them and my success rate is about 25% at best. I have changed every cap, usually 1000uf or 2200uf only for it to start momentarily and blow an IRF840 or something else on the board. Everything usually checks out so I give up. If the PS has an IC, trdstarlet has a point, it might be bad...but it could be multiple caps, an unmarked zener diode and a broken trace. I would just replace it, the board does not consume a ton of amps.


Chris

[Trdstarlet]

I’m still a novice with these slot machines, so I don’t want to do anything that could damage it further. My main concern is that I don’t have the schematics, so I could accidentally connect something incorrectly. Parts are scarce, and it’s possible the previous owner did some troubleshooting and may have hooked up a wire in the wrong place.

Right now, my plan is to add the new proposed 5V power supply, but I still need to power the rest of the unit — the CRT, coin mechanism, hopper, and all the other components. Interestingly, the isolated portion for the CRT includes something new to me: an EMI filter. I hadn’t heard of that device before.

Looks like I’m in the right place, and I really appreciate the help here.

[Trdstarlet]

Well I was looking this thing over a bit closer and saw this missing capacitor... If not the cause it's a culprit.

[Chris-socal]

Probably not an issue. They likely used the same board for different voltages and that cap is used in another version. Unless you see something indicating the cap is physically broken off and the leads are still soldered in.
Those EMI filters were only needed in casinos, not typically important in a home environment.as long as they are passing power its ok to leave it.

The monitor works so what is there to figure out? Its obviously getting power….if it wasn’t you would not get the color setup screen.

[Trdstarlet]

The transformer is smoking, and it crackles if I leave it plugged in for a few minutes. I’m sure it would fill the room with the smell if I let it run any longer. I’ll have to find a way to bypass it as well. But from your comments "as long as they are passing power its ok to leave it" so should find other power source and deed it via the EMI to then monitor?

[Trdstarlet]

@Chris & @Jay — Clearly, you guys are more experienced with these types of devices. I’m just trying to be cautious so I don’t cause any more damage to key components.

I’ll have hands-on time with the rest of the machine tomorrow when I get home for the weekend. Now that I’ve got a game plan for the 5V portion of the power supply, I need to tackle the rest of the cabinet: CRT monitor, hopper, and lights. Am I missing anything?

How would you approach that portion of the machine? The more I think about it, the more clarity I get: power sources (two or three), monitor, game board, hopper, and lights. Maybe I’m just overthinking it.

[jay]

The CRT seems to have good power, the video input signal will come from the MPU.
My current hypothesis is that the test pattern is either being generated from the MPU or is a default of the monitor when it is absent a signal video signal.

Most of the other functions such as coin acceptance, bill acceptance, lights, sound etc will likely fall into place once the MPU board comes back online.

IF you think about this in terms of a car.
If your transmission falls out. You get the transmission replaced.
Its unlikely your going to have problems with the sound system, headlights, starter or other aspects of the car.

While we might be overly optimistic it seems like you have a power supply problem. Lets get that sorted and then go from there.