Here's something a little different. I'm going to start logging repairs on various boards I have lying around that need repairs. I'm mainly going to focus on games and boards I have a lot of experience with, and some repair techniques that I've used over the years.
Solenoid Driver (Bally / Stern 1977 - 1981)This board is typical of the boards that have never been repaired or reconditioned. This is a very important component of the Pinballs of this era and if they are not attended to, they can damage OTHER components of your game - particularly displays.
The problems with this board are not visibly noticeable, and you probably would not know there is a problem until you tested it. I plays fine in my Paragon... But there are several issues with this board....
Look at the large silver capacitor.. That's a factory cap that was designed for 10 years operation.
Look at the large blue capacitor.. again ..That's a factory cap that was designed for 10 years operation, and it is leaking !
Measure TP2 and TP4 to ground... Hmmm.. Both over 200 VDC. This is a HUUUGE problem...The HV to the displays is no longer regulating, and I cannot adjust the pot to lower the voltage to 175 - 185 VDC...
But The boards works ???
It is actually DAMAGING the displays, and if you had an Altec MPU board in the game... That could be nasty...