Dreaded Red LED on 1270 MPU with cycling of VFD Netplex Error.

[Ash100]

NLG really needs a WTF Button in the Message Icon. Lol.

Pulled a non working S2000 out of storage to build. It's parts complete but can't get past this non-boot issue I'm having.

Original 1270 MPU (Varta and U16 removed) and Daughter Card with OEM Software, 6-6-3 Display, Touchpad, Printer, WBA and Backlit Reels. Pretty standard stuff.

Power up the machine and I get all MPU LEDs illuminated with blinking Red in 1 second intervals. The VFD will display the Netplex Link Down Error as the Red LED blinks. It's almost like a power problem the way it flashes, goes blank, flashes, etc.

So, troubleshooting wise, I grab a few spare 1270 Boards and swap over the Daughter Card. No change. Try a different Daughter Card with same Software, no change. Tried different OEM Software, still no change.

Tried different Main Power Supply, no change. Started disconnecting all of the Netplex Devices one by one until I had nothing left connected. Even a few SENET Devices

It did boot once after hooking everything back up, but did It's blink thing 4 times before finally coming online. It booted to the point of giving me Machine Type Mismatch, so I shut it down. Now it's back to the non-booting stage with the Cycling Power/Red LED.

Original Game Chips were 363's, so I pulled them and put in 598's. No difference.
Installed the 224 Clear Chip for grits and shins, have 2 solid green LEDs (top 2) and a blinking amber (3rd) LED. nothing more.

Haven't replaced the Backplane yet, for obvious reasons.  But I guess that's which direction I'll head in next, unless someone has something else to try.

Thanks,

Curtis ash100

[Stayouttadabunker]

wow...you've done a lot so far.
okay...even swapping MPU's didn't work in this "non-working S2k".
My guess it's either a loose, or dying power supply, a loose or broken PDU ribbon cable, or that little backplane 8-pin chip corrupted?
Pull out that lil' chip, thow in a good one, re-install MPU, and see what happens?
I'm guessing you've also tried a known working MPU with known working chips from another known working cabinet?

[Ash100]

Update,

Partially figured out....

Swapped the Backplane, tested solder joints on old one once removed, to include the 2 fuse holders, power in and other connections. All look good. Even swapped EEPROM as Mark suggested prior to pulling Backplane.

Backplane didn't fix it. Went back to MPUs, tested 3 known working ones, still no go. Finally the 4th MPU allowed the game to boot.

Installed the previous 3 MPUs, same problem. Installed all 3 into a working machine, no issues at all. Very strange.

Something in that machine must be out of limits just enough to pull down a weak MPU?

I'll keep troubleshooting and maybe I can locate a questionable component causing the original failures. But at this point, I'm where I can Clear and Key the machine.

Thanks for the inputs.

Curtis ash100

[Ash100]

Latest update....

I was able to get the machine set up and programmed. Everything seems fine as far as actual game play goes. No issues with the Touchpad or Displays, Buttons all work etc.

Sometimes though, upon power up, I'll get all of the MPU LEDs illuminated to include the red one, and nothing more. It just freezes like that. I can cycle power and it boots normally afterwards.

At the suggestion of Lookes, I re-tried  all of the previous MPUs with the Bill Validator removed and Harness disconnected. Unfortunately, those 3 are still doing the same thing. 4th LED (amber) and Red LED both blink in 1 second intervals with the VFD flashing Netplex Link Down with each cycle.

The machine had a dead WBA in it to begin with, but I doubt that was the issue. I was able to put together a good WBA Transport and Sensor Head that works in that machine, and tested a few others I had on hand.

So, I suppose that I'll call this one Topic Solved, although I really don't have a solid fix other than 1 working MPU out of 4 spares. I would like to have the other 3 checked out though, maybe there's really something wrong with them. Although they were tested last year and labeled as Good.

Anyway, thanks for the tips and Happy Thanksgiving!!

Curtis ash100

[Stayouttadabunker]

I marked this Topic as "Solved" for you Curtis although it bothers me that the 3 MPU's work in a known good cabinet,  but not with this one...that's what made me suspect the backplane EEPROM chip.
I must totally agree with you that something in this cabinet makes those other MPU's seem bad.

[Ash100]

Thanks Mark.

I'll keep looking at things, but I'm really just about out of ideas.

Curtis ash100

[dailey]

Ash100,

I hope your problem is solved, but I wanted to throw a couple more ideas your way in case it acts up again. If you have a Spectrum progressive display, keep in mind it's a netplex device and you should try unplugging it. Also, if you have a Sentry bill validator bezel, it is in the netplex circuit. You can try disconnecting and isolating it. The wiring to the sentry can also be pinched by closing of the door if the wires aren't tucked out of the way.

Besides isolating the netplex devices as you have already done, there is also the harnesses to be concerned about. You can isolate these one by one by disconnecting them at the backplane Netplex connectors (4).

One thing I have read about the 1270 board, though I doubt it is the issue here, is that the 22uf capacitor can go bad and cause a netplex down error.