Bally gamemaker CPU from a slant top into an upright not working. Mains?

[bobinphx]

I have a perfectly working 1995 Gamemaker upright. I have refurbished everything, including new caps everywhere. Recently, I ran across a slant top gamemaker from 1996 for next to free. I now have a lot of spare parts for the upright. One of the things I wanted to do is have two motherboards (cpu's), but I cant seem to get the slant top motherboard to work in the upright.


Here is what I have done so far.
I have replaced the 4 caps on both motherboards.
I have replaced the batteries on both boards.
I have moved all the game chips to the upright motherboard and they all work great!.
I have verified that both boards are revision "F".
I have checked for bent pins and bad solder joints on both boards, none were found.


When I put the slant top board in the upright, I get all the green lights to come on, the reset comes on and goes off, the bill acceptor does its startup dance, but does not light up fully. The hopper jogs a little bit and the hopper board flashes 1 time. The screen does not come on and everything just stops.


I have tried a clear/debug chip, with various combinations of dip switch1 (all, 8, 7+8, 6+7+8, etc) to no avail. I have tried the reset button on the motherboard. I have tried the reset key.


In reviewing the two boards, all jumpers are the same, the graphics chips are the same,,, but the mains (m0 and m1) are different. Here is the breakdown.
slant top M0= v7m1002f0004-24, M1= v7m4002f0004-24.
upright   M0= v7m1000c2104-24, M1= v7m4000c2104-24 (these work)
for reference the graphic chips are  G0=v7g00000004-14 and G1= vg200000004-14, on both boards.


What's your opinion? Did I miss anything? Can I swap the mains from one board to another for testing?  Do I need to find the exact same mains as the upright or is the a universal main set? And finally, where can I get new mains?


Thank you in advance for looking and helping.

[shortrackskater]

Swap the mains and check the other board that way. I believe you'll have to do a clear again though.
If that works but no games are recognized, add one game from the board where the mains came from.
I'm definitely NOT a pro at this so another member may need to chime in!

[bobinphx]

I had thought of that, but I was not sure. I am worried that it might change all the settings on the mains (which I have since written down, just in case) if/when I put the mains back in the working board. Yea, I am a bit cautious!

[bobinphx]

changing mains in the slant top board resulted in no change. changing the graphics chips resulted in no change. Reseating all socketed chips resulted in no change. I am at a loss.

[Slotman]

Going off memory there was a V7000 and V7200 variant.  Are both boards the same?I can tell you that the board is shared upon platforms.  I have a few Bar Tops back in the day that I took the board out and moved it to an upright.  The board tray had to be changed is all.I do recall a small 6 or 8 pin chip that was the jurisdiction chip and if that was not compatible the game wouldnt boot.  It has a dot matrix printed label on it.
Also, I have a working v7200 board with Multi Denom mains on it if you ever need it.

[Slotman]

Going off memory there was a V7000 and V7200 variant.  Are both boards the same?I can tell you that the board is shared upon platforms.  I have a few Bar Tops back in the day that I took the board out and moved it to an upright.  The board tray had to be changed is all.I do recall a small 6 or 8 pin chip that was the jurisdiction chip and if that was not compatible the game wouldnt boot.  It has a dot matrix printed label on it.
Also, I have a working v7200 board with Multi Denom mains on it if you ever need it.

Here is your jurisdiction chip.

[Slotman]

Also, if you are running any 512K EEPROMS your pin #1 will not start at the edge of the notch but will be indented toward the other side (if that makes sense).  The 1MB eeproms have enough legs so notch to notch.  The 512K just line up the "back end" to the back end.I cant recall if just that one game wont be recognized or if the whole board will fail to boot.Just brainstorming and throwing out ideas.

[bobinphx]

Looks like I try the jurisdiction chip swap from the working upright board to the non working slant top board!!

As the the chips with less legs, thank you for the reminder and I have been very careful to be sure the game chips that are "short" are back from the "U" in the chip socket.

btw. a historical thank you to the bally engineer who made the call to use the more expensive milled sockets!!! the non milled sockets, like in pinball machines, are the worst!

[bobinphx]

Swapped the working u3 chip from the upright board into the non working slant top board. no change when installed in the upright.. still nothing.

So, I am starting to wonder if maybe the monitors between the slant top and the upright (working) are different. Maybe the mother board is up and working, but not able to light the monitor?  I also did notice that the back plane board was different on the slant top. maybe that is a clue. I did just now check the monitors and they are both tatung vs14428 model numbers. The upright has its plug (molex) under the monitor and the slant has its plug (a slide in) at the rear. Maybe thats also clue?

[bobinphx]

additional observation. The red light on the Motherboard is lit at start up and it does go out. That would tell me that the power is good and that some part of the motherboard thinks it ok and is running.. still at a loss as to what the problem could be.

[bobinphx]

gave up on the additional motherboard. Without better documentation was to what is what on the board, I give up.