Author Topic: WMS Model 40x Lower Power Supply Replacement (Read 304 times)

Rock501 · « **on:** February 16, 2026, 06:23:20 pm »

Hello,
I have a WMS Model 40x (non-Dot) "Reel Em In" machine and recently replaced the lower power supply using an ATX computer power supply modification as described in previous posts. When I power the machine on, I get the magic 1 gong, the door, reels and top box light up, and I hear the bill validator, but then no reel spin or messages on the door, and the game will not start. The CPU is new and the I/O board shows all LED's lit (see attached pictures). As a newer NLG member with limited electrical skills, I would appreciate any advice or suggestions on what might be causing this issue (bad chip, CPU)

, and what I could possibly do to get this cool machine running again. Many thanks. EdS. (Rock501).

playklax01 · « **Reply #1 on:** February 17, 2026, 06:29:35 am »

You have the 5 lights and the gong, so that's good news. It's passing the initialization tests but not continuing the booting process. I'd recommend starting with the basics until we can discover more. Pull out the boards and inspect top and bottom for any foreign matter/tape/etc. Check the chips are properly seated and tight. Do you have a clear chip? Would help to do a clear, just to know you're starting with a clean slate.

dragster73 · « **Reply #2 on:** February 17, 2026, 07:43:34 am »

Inside the steel power supply box is separate voltages for the reels and lights. These voltages are fused and separate from the internal power supply you bypassed with the new supply. I would recommend opening that up and checking the fuses mounted to the circuit board inside it.

Rock501 · « **Reply #3 on:** February 17, 2026, 09:07:52 am »

Thank you playklax01 and dragster73 for your replies. I'm away for a few days, but will follow up with your recommendations asap. It is great having knowledgable members and amazing resources on NLG.

Rock501

Rock501 · « **Reply #4 on:** February 24, 2026, 01:22:47 pm »

Hello,
This is a follow up to my recent post about my WMS Model 40x (non-Dot) "Reel Em In" machine. I replaced the lower power supply using the ATX computer power supply modification as described in NLG previous posts. When I power the machine on, I get the magic 1 gong, the door, reels and top box light up, and I hear the bill validator, but then no reel spin or messages on the door, and the game will not start. The CPU is new and the I/O board shows all LED's lit. As recommended by other members, I checked all of the fuses, the boards look good, and the chips are all seated. After powering the machine on, it seems that all three reels "jump" slightly but will not spin. I don't believe that I can clear the machine unless the door messages are working. Could a bad chip be the problem?

I appreciate all of the NLG member recommendations and welcome any additional suggestions to get this cool machine working. Many Thanks! Rock501

dragster73 · « **Reply #5 on:** February 25, 2026, 07:28:50 am »

Did you open the power supply metal box and test the fuses on the PCB board inside of it?

Rock501 · « **Reply #6 on:** February 26, 2026, 11:38:39 am »

Yes Sir, Recently replaced one of the fuses in the PCB board in the power supply box. I think I'm close. The door coins/bet lights are now working. Once I clear the machine, I think it might come back to life. Thank you and all of the NLG folks for the information. This is an impressive site with an amazing amount of resources. Rock501.

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