Bally Space Invaders (Bally, 1980) Display issue

[sesc33]

Recently purchased a space invaders. The machine had display issues when I purchased it.
The displays flickered and did not score properly.
I resoldered all the header pins and replaced the 1/4watt resistors with the 1/2watt resistors. Displays do not flicker anymore. They score correctly except displays in postion 2, 3, &4 do not display 5 or 9 in any segments.
The credit and ball in play display does not show the digits 2, 3, 5, & 9
Shows only 0 and 3s
When it put it in test mode, the 1st display flashes 0 through 9 properly. Displays 2,3,&4 flash 0,0,2,3,4,4,6,7,8,8
Ball in play display flashes 0,0,3,4,4,6,7,8,8
Tried changing the display location but no change.
Any help or suggestions would be greatly appreciated.

 

[faralos]

Sounds like the driver board may be shot

 

[sesc33]

The solenoid driver board?

I have replaced capacitors C26 and C23 as well as all the components in the high voltage section. i have test all the resistors, diodes, and transistors they all test with in specifications. Have also checked all the voltages at the tests points on board and they are with in specifications. The first display works perfectly. Would it be possible a connector issue, ram, or pia chip?

 

[IBEWBrother]

I'm not an authority.....but what tells the display WHAT to display. That's where I would start. Good Luck.

 

[Shockman]

It sounds to me like a mechanical problem, not an electronic one. I don't know what the switches are. Some are a disc, some are drum. Every contact point needs to be clean enough. This is just a guess.

 

[spalmer]

Recently purchased a space invaders. The machine had display issues when I purchased it.
The displays flickered and did not score properly.
I resoldered all the header pins and replaced the 1/4watt resistors with the 1/2watt resistors. Displays do not flicker anymore. They score correctly except displays in postion 2, 3, &4 do not display 5 or 9 in any segments.
The credit and ball in play display does not show the digits 2, 3, 5, & 9
Shows only 0 and 3s
When it put it in test mode, the 1st display flashes 0 through 9 properly. Displays 2,3,&4 flash 0,0,2,3,4,4,6,7,8,8
Ball in play display flashes 0,0,3,4,4,6,7,8,8
Tried changing the display location but no change.
Any help or suggestions would be greatly appreciated.

U11 on the MPU board controls the score displays. Swap U11 and U10 and see if the problem is the same and report back. Both chips are the same so no worries. It could be that part of U11 is bad.