I have a Spiderman Gen 1 CPU I am converting or attempting to convert to a Gen 2 CPU for
use in a Mars God of War.

When looking at the game ROMs, U2 and U3, the files appear different in size between the Spiderman
and Mars God of War.

In addition to the wiring changes to the board do I need to burn some new U2 and U3 game ROMs? and what
chip would apply?

I have read that the game roms should work until later games, but it seems I have a problem somewhere. I have got the board to boot with the U1 MOGW eprom, -- into attract, but no controls will be accepted such as the test button and coin switches. I know they reach the RIOT by seeing a state change with a logic probe.

Quick Scan will pass. But I have hosed that up by attempting the match the board with the Mars God of War Schematic in the area of the U1 PROM.

Hi Chris,

Thanks for the response. I did the procedure outlined in pinwiki. I found two problems. Connections to the PROM2 pins were dead-ended and did not complete the circuits for A10 and A9.

I added a wire from PROM2 socket, pin 21 to Z12 pin 10 to complete BAB10. (step 3 of Pinwiki info)

I added a wire from PROM2 socket, pin 22 to Z10 pin 10 to complete BAB9. (step 4 of Pinwiki info)

PROM2 pins 21 and 22 only went to PROM1 where the original traces were cut.

I just burned MGOW PROM1 into a 2716 Eprom. It verified fine. As I have the complete data files for both Spiderman and MGOW, I noticed that the U2/U3 files were different sizes.

If I remove my 2 added wires, the Quick Scan passes. With my wires added as above, Quick Scan goes into error 8. I believe this is because with the added ground the PROM1 is ignored - good or not.

Without the added wires I can get the machine into attract, but then no inputs are recognized. That's when I did the circuit investigation regarding the conversion process and found BAB10 and BAB9 were dangling off of PROM1.

What's going wrong with this??? Do you think I should burn another 2716? What do you think about the necessity to add wiring to complete the BAB10 and BAB9 circuits?

Schematic for MGOW follows:

img045.jpg

The board has been modified precisely per the information as provided by Pinwiki to upgrade to G2. The problem remains the same. There must be a problem with the board unrelated to the G1 to G2 modifications.

The board boots consistently using the Quickscan on the bench. There are no error indications. I have replaced the 6802 processor and all three of the riots in working this problem. The 5101 is replaced as well in a grasping move for a solution.

In the machine there is a weird problem. When powered on the board generally doesn't boot up with either the Quickscan attached or normally. If the reset pin 40 of the 6802 is grounded, nothing happens. If the power switch is toggled, it generally doesn't help but sometimes it may work. HOWEVER, if the power connector is removed and quickly replaced the board boots every time. The power supply is measuring 5.08VDC, with less AC than my bench supply - measured at the CPU board. It seems software related more than the reset circuit and the 5VDC supply.

With the Quickscan attached in the machine, the displays do not display. When the board boots without the Quickscan, the displays are working. The control lamps work well when the board boots. Machine will not coin up, nor will the test button function in the game mode.

As a side note, this is a nice clean board, with no corrosion -- just doesn't work correctly.

Also, MGOW uses only one 2716 eProm located in PROM1. I may try a different eProm to make sure it isn't a faulty device.

Any ideas on what to try next?

Yes I meant 6502 for the processor.

The displays were toggling between high score and zeros. I changed the switch settings and now the scores are zeros with no switching. I will have to check the switch settings again.

I will check on Ed's U2/U3 adapter.

I will try a different game PROM.

Yes the game is unresponsive in attract where the controlled lamps are cycling.

Hi Steve,

I can see the test button state change at the U4 Riot pin using a logic probe. I suppose
there still could be switch matrix problem causing the ignored state change. I will make
a connector as you have to see if that will work without the other switches connected.

I also hear the double relay click upon entry to attract which sounds like normal.

Thanks all -

Barry

Thanks all...board is now working. I bought one of Ed's U2/U3 adapters, burned a 27512 eprom with the combined images and this solved the problem.

Cro-pinman was on target with the U2/U3 as possible cause.

I still have to sort out the power up problem likely associated with either the machine power supply or the reset circuit of the board.

To repeat, if I power up the game it doesn't boot. If I ground pin 40 of the 6502 nothing happens. However, if I pull the power connector and replace on the CPU board, the board boots.

I find nothing wrong in the power supply, the 5V is measuring a bit less than 5.1V at the CPU. There is almost no AC measured on the 5VDC.

When powered on with the Quickscan attached. There are weird results in the display. The numerics look OK but are moving rapidly with an F inserted somewhere between numerals. The display is too fast to ascertain what might
be getting "F'd" A quick removal of the power connector and reconnect and the quickscan is running fine, no errors.

I thought the same and replaced it a while ago. I have replaced the cap down in the cabinet bottom, and it was
oversized, maybe 10,000uf or 12,000uf. I also replaced a shorted bridge rectifier. Just a weird problem.

Thanks for pointing me to the little replacement board for the U2/U3. I didn't know about that device and it solved the problem.

Chris,
I agree, I'm going to try it in my Black Hole and see what happens. Otherwise you are going to have to
make visit down my way and help me sort this board. It might be time you make a visit to Branson.
Barry