Early Game King MPU won't boot

[badlanding]

Greetings! I'm a tech savvy guy with an extensive electronics background as both an engineer and technician and I'm attracted to the electronics of the nineties and two thousands, my heyday!  Anyway I am based in Vegas for my job now and have plenty of time on my hands so I started buying cheap used Game Kings. What a hoot! I've been disassembling them and restoring them for fun and I've put new Ceronix monitors in a couple of them. We all have fun playing them.


Anyway I have an early Game King with the interfaces mounted on a tray above the mpu. For some reason my iPad won't won't switch to number mode but the mpu is a zero thirty eight.  I stuck a new Ceronix monitor in the box and I get a confetti screen.  The red light on the MPU flashes which I understand indicates that the CPU is not booting. Memory battery is new, I get the keychip menu when I put a zero forty in it. I took a zero thirty nine board out of another working game king and stuck it in, same confetti screen, same flashing red light, same keychip menu with the zero forty.  Stuck the board back in the working machine and it works properly.


I thought that perhaps the power supply was the culprit, voltages were thirteen and twenty five but I recapped it anyway. No change. I'm beginning to believe that the mpu is looking for some peripheral which it doesn't find but I don't have a troubleshooting manual or backplane or peripheral schematics. There is an LED on the backplane which is not lit and there is another LED mounted to a circuit board attached to the mains distribution box and it is unlit as well. This circuit board is connected to the backplane with a twenty six pin ribbon cable.


Any ideas as to why I can't get an mpu to boot in this box?


Thank you!

[Tilt]

Greeting Badlanding,

  I think it's fun to pick up non-working games and get them running again too.  I actually enjoy that more than playing them. 

You have the classic signs of a non-booting MPU.  The blinking red light and confetti screen.  It's usually caused by one of three things.  Game software installed incorrectly (chip backwards, bent EPROM pin, chips installed in wrong socket, etc), bad MPU board, or bad power supply.

The early MPU board 3802 only supported EPROM based games, the 3902 board supports EPROMs and simm cards.  They're interchangable, but the screen usually shifts due to different screen resolutions of the two boards.  Did the 3802 board work in the other machine?

What type of cabinet do you have, 13" or 19"?  From your description it sounds like it could be a bad power supply, but you said the voltages were +13 and +25 which would make it unlikely. Usually they will be low if the power supply is failing.  If you have another one I would swap it just to make sure. 

You could also pull the I/O try so it's not connected to the motherboard and see if it boots that way.  If it does you'll get some other errors (Coin-in Jam/Meters Disconnected). 

Those two LEDs are normally not lit.  The one connected to the motherboard VIA the ribbon cable is the comm board.  It's used for interfacing with casino back end systems. 

[badlanding]

POWER SUPPLY IT IS! I connected a bench supply set at 13V to the 13V input to one of the 3902 boards and I could watch the LEDs as the board booted correctly.  So I took the motherboard out of the box and connected the 3902 board to the motherboard and repeated the test, the MPU booted correctly. So I reassembled the whole thing, ran a couple of jumper leads out of the lock hole on the MPU, disconnected the Gameking power supply, and powered the whole works from the bench power supply. It booted up correctly and I was able to configure the machine and adjust the monitor and touch screen and, more importantly, play games!


So I need to figure out what is going on with my power supply.  This is the only Gameking that I have with an early style power supply so I guess I'll trace out the schematic and troubleshoot it.  I keep getting a warning to call attendant because the line frequency monitor is not working so there is a little more in that box then just the power supply itself.  Thanks for your help! 



FYI The 13V supply powers the logic and lights, the 25V supply powers the audio output. So you can run the entire machine on 13V without any audio.  It requires 1A +/- depending on how many buttons are lighted.

[Tilt]

Great!  You have more electronics experience than most so you may be able to repair the power supply.  The re-cap didn't seem to help which means it won't be a simple repair.

You're correct, there is another power supply output used by the machine to determine the line frequency.  If it's missing you'll get the line frequency error message that you get when running on your bench supply.

 The +13VDC is used to power the MPU logic, but it also needs +25VDC for some other functions (such as the audio as you figured out). 

Please post a picture of your machine from the outside, and with the door open.  They have to be under 1MB each to post, so resize as necessary.  After I see what type of cabinet you have I can send you some wiring diagrams that maybe helpful to you. 

[badlanding]

Thank you for your help! I replaced the power supply with an easy to find new style, it is the same physical size but required some repinning of the main connector and replacement of the mounting plate. I replaced the monitor with a Ceronix LCD and everything works great!  The bill acceptor even takes new $20s!

[Tilt]

Glad your got it fixed up and thanks for the followup .   

IGT had two different types of 13" cabinets.  The later 13" cabinets had electronic ballasts for the florescent lamps and the newer game king/S2000 power supplies will work in them without repinning anything, but you have to work out the mounting.  The older one like yours had transformer ballasts and starters and to use the new style power supply you have to re-pin the connector so the AC power input is on the correct pins.  You got that figured out though, great job!

You can always upgrade the validator to a newer model if you want to be able to use later series bills.  Enjoy your machine!

[Ash100]

Hello, sorry to jump in late but just found this thread.
I have an early Game King that won't do anything too and suspect it's a bad power supply, but not sure.
The monitor will not come on, the buttons do not illuminate,  the BV won't accept bills but all of the florescent lights come on.
I believe it's an older style power supply, inside of my game looks just like the above photo.
Question is, can I use a newer S2000 power supply in place of that one without re-pinning the plug?
Ballasts were mentioned above too, so to be clear, if my machine uses the Electronic DC Ballast (IGT 195 076 90) I shouldn't need re-pin?
Thanks.