Bally Mata Hari (Bally, 1978) problem

[JimMcGowanInlet]

The house I brought the previous owner left a Mata Hari game in the basement. The game had the service manuals and after doing the tests in the manual I suspect the MPU board is bad.

Following the manual, I get 5 flashes on boot. The procedure says check for a short on U9 pin 4 to U11 pin 37 and 38. I have a short from 4 to 37 and 4 to 38. Between 4 and ground I have 8k. From another forum recommendation I also checked F4, it is good.

I have serious corrosion around the battery that has spread into the board which I have read usually makes the board toast but the instructions say to replace U11.

I see replacement boards on line but I am concerned that if I install a new board I may fry it since I do not know the condition of the rest of the boards. Plugging the unit in, i get the 5 flashes and nothing else. Since everything powered up and didn't smoke and nothing else appears damaged or burnt, is it a safe bet to replace just the MPU or do these machines often fail as a system.

The rest of the machine is in very good shape except the rubber is dry rotted and a few bulbs are burnt out.

My electronic skills are as old as the machine so any heavy repairing is not an option for me, but if there are any inexpensive things i can try on the old board first, common part failures, ect. I could try U11 and also replace the battery and clean the corrosion if the odds are in my favor. Any advice on getting the machine in working order is appreciated.

Jim

 

[Rod71]

Easiest to just replace the mpu with an aftermarket one.

In the meantime you could test the voltages from the rectifier board which is also a weak point on these games.

 

[spalmer]

I have certainly seen boards in worse shape (judging from your picture). Check for voltage at TP3. It should be about 22 volts. If there is no voltage there, you will not get the sixth flash. Also, disconnect the sound board and try booting with it disconnected. It can also cause it to lock after the 5ht flash. I have several of these boards and a test bed. If you are willing to ship the boards, I would be willing to test each of them and give you an idea as to if they are worth repairing. These boards are pretty simple and easy to fix. Send me a Private Message if you are interested. I may even be able to walk you through a few steps over the phone.

Can you post a better picure of the lower left corner (area to the left of the battery).