Hello, this is my first post on Pinside but I've read hundreds.

So, I just got a Xenon. The game was working fine when I picked it up but after getting it home now it does not start up. Only the GI lights come on. The LED on the MPU does not flash. I've been reading thru the forum trying to figure out what to do. I have disconnected everything from the MPU except the J4 with the same result. I understood the next step is to test the power supply. That is an AS-2518-54 board. I tested by putting the black lead on GND and using the the red lead to touch TP1 - TP5. I got the following readings:
TP1 7.8V
TP2 O.L
TP3 0.2V
TP4 O.L
TP5 O.L

Then I read somewhere to unplug the output connectors from the board and to switch to AC voltage for TP4. After doing that, I get the following results:
TP1 7.9V
TP2 184V
TP3 13.3V
TP4 7.3V
TP5 45.6V

I also have Bally KISS with the same MPU board. I took the board out of Xenon and hooked up the J4 from KISS. I got 7 flashes. I take that as a good sign for the MPU.

I am assuming I have an issue with the Xenon power module. It looks like I can get a replacement board online to replace the AS-2518-54.

Is there something else I can test regarding the power module to verify that it's the board itself that is the problem and not something else?

Thanks. I have measured the voltages again with only the J6 connected. Previously the J5 was also connected.
Now I get:
TP1 8 VDC
TP2 2.9 - 4.2 VDC (way off from 230 VDC listed in the schematic)
TP3 13.3 VDC
TP4 7.3 VAC
TP5 45.6 VDC

Are the results from TP2 indicating a fault with the board?

Wow replacing those diodes would be a lot cheaper than replacing the board. The fuse(F2) seems ok - I took it out and there is continuity across it. R3 is measuring 199 ohms. But looking at the schematic closer, isn't it the J5 connector for TP2?

With both J5 and J6 plugged in the voltage at TP2 is 184 VDC. The schematic says 230 VDC then (UNREG 190). Is the resistor dropping the voltage appropriately or should TP2 really be 230 VDC?

The game was fully working. I played a few games on it before buying. Not sure about a driver board. Is that the power module or MPU module? Block diagram in the manual shows the MPU's only input is from the power module.

On the power module after plugging everything in, TP2 is 194v. On the MPU board(with all the connectors plugged in) I am definitely not getting 5v. TP1, TP2, and TP5 all read 0.25v. TP3 reads 0v.

With Xenon's board hooked up to the J4 from my KISS the LED does flash 7 times. Hooked up to the Xenon - no flashes. This leading me to believe there is a problem with the J4 connector. I'm kicking myself because onsite I had unplugged it from the board when I did not need to.

Yep. I mis-connected a connector on the SDB. I had disconnected onsite then realized I did not need to do that and reconnected it back right away. This connector is split into two connectors and I think it misaligned the bottom one. I found this when testing voltages as advised by @Knxwledge. Unfortunately, the game did not boot even after connecting it correctly. Will be posting the results in response to @Knxwledge.

I found the driver board and I see now how it inputs to the MPU board. I did not getting any voltage readings at TP5, TP3, TP1. I saw in the schematic where J3 powers those points so I inspected that connection and found that I misaligned one of the two connectors as mentioned in my previous post.

I got it connected correctly and... progress. When I powered on the machine I heard a solenoid engage and also heard a loud buzzing in the cabinet. I went to check the voltages again and they were still zero (TP2 was at 185v though).

The coil that engaged is the one for the top saucer - and it does not disengage. I powered down the machine and see that the F2 fuse is blown. This is a 3/4A fuse. I could not find this locally, but I did find .5A and 1A fuses. I've put in an order for 3/4A fuses from Amazon.

Can I continue testing with either a .5A or a 1A fuse? If so, is there something I should do before powering up again?

Looking at this connector(s) more closely, I don't think it's a broken connector but one that has been rebuilt previously. It's two 12 pin connectors. Matching the wire colors to the schematic, it looks like pin 13 should not be connected when using the two connectors. That would be a brown/green wire coming from pin 25. I see the wire coming out of the connector from pin 25 but not going anywhere. It's snipped and wrapped around the other wires.

Hopefully that means I can skip rebuilding the connector and just make sure I seat it correctly. Unless I need to do something with the brown/green wire?

EDIT:

".. it looks like pin 13 should not be connected when using the two connectors.."

This wrong. The two connectors are for the first 24 pins. The 25th pin has no connection. Realized this testing continuity from the power supply to the connector as I paid more attention to the wires. You guys are so patient.
.

Yes, will rebuild it with a kit from Big Daddy. Not something I've ever done before. Looks like I'll need to get some tools too - crimper, extractor. I think I've seen some posts on here with good advice on how to do it.

I checked the schematic and it definitely looks like it needs pin 13. I was wondering how the machine had been working so I pulled the board and on the back there is wire soldered from pin 25 to pins 13 and 14.

While I had the board out I put it in my KISS to test voltages. I did it with only J3 connected.
TP1 .03V
TP3 .03V
TP5 13.62V

The KISS SDB is much better - 5.37, 5.37, 15.29 respectively.

So I take it the board itself has a fault. Not sure I have ruled out the connector, though. I don't think putting the KISS board(to test the connector) in the Xenon will help as it doesn't have the hack on the back. I guess I could try to do the same hack as lacking in soldering skills as I am. Just afraid to have two broke SDBs.

I got brave and decided to try to add the jumper wire on the back of the SDB from KISS to test in Xenon. I flipped the board over and it too has the jumper wire. LOL, I didn't even check for that last night.

I plugged the J3 connector(s) into SDB and tested the voltages. TP1 and TP3 read like .03V. I switched the machine off right away to prevent any damage to the board just in case.

Now I'm thinking the connector is bad and hopefully not the board. While waiting for the new connector, is there anything else I can test to verify the fault is not happening prior to the connector? Like maybe testing the connector in the wire harness.

And possibly the connector(s) have a fault as well. Seems the KISS SDB should work in Xenon.

With the KISS driver board in Xenon, the voltages at TP1 and TP3 are low 0 - 0.003v. I plan to try and test continuity and voltages from the J3 connector back to the power supply. I have an order for new connectors and pins as well.

Xenon boots!

Thank you @Knwlege and everybody.

It boots using the driver board from KISS with the J3 plugged in correctly. A couple coils don't fire. I think the components may be bad. And KISS doesn't use them. Thinking of replacing them.

As for the Xenon driver board I'm going to start with replacing the 5v regulator.

Xenon plays!

I added the two missing transistors to the KISS driver board that I'm using in Xenon and that got it going 100%.

Will try to fix the Xenon driver board and of course fix the J3 connector when that comes in.