should have bought a HOMEPIN rectifier board.  
The name "ROTTEN DOG" says it all.
these after market boards that are not made in Australia are nothing but trouble or at least just a patch up job until you can find a proper replacement.
when you have seen as many as i have and the trouble that they cause you will understand what i mean especially when you have to send boards back because they just plain forgot to include must have components on their boards and instead of doing a recall they just wait until some one sends their board back then they supply a replacement.

I have lost count of how many machines i have repaired where the customer has bought an after market board and installed it to find out there are problems and they tell me "must be something wrong with my machine because it's a brand new board".

I don't know but i recon  for legal reasons we can't start a thread with a title "after market board name and it's know design fault"

there is one driver board that is designed and marketed by one company that causes a ridiculous amount of led ghosting on the playfield in any wpc95 machine that it is fitted in that has leds on the playfield inserts.
the ghosting is so bad that if you have standard incandescent lamps fitted instead of ghosting the lamps filaments of the lamps that are not supposed to be lit GLOW RED        
When i contacted the manufacturer this was their reply
Hi Andrew,
thank you for your mail.
There is a software bug in all Williams7Bally WPC machines. In the lamp matrix the light time to the next column is overlap the old one. That mean the next column starts to light up before the old one is completly off.
With normal lamp bulbs you didn’t notice that. But if you place LEDs to the inserts you will see this effect because the LEDs are “faster”. Additional our board is usung MOSFETs instead of normal transistors. This will increace this effect too.
 

FYI it was for a Medieval Madness (wpc-95 not wpc)

and another one from another company

Hi
I am in the process of repairing a XXX-XXX Bally Voltage Regulator / Driver Board and I have a question regarding Q17 to Q19.
The gate for these 3 fets on the continuous solenoid circuits are directly connected to Connector J4 pins 9, 10 & 11 and use a pull down resistor on the gate.
All the fets are controlled through a 74hct154 binary decoder and a 74hct240 buffer invertor.

My problem is Q17 to Q19 need +5 volts on the gate to operate the solenoids they control but the output on the mpu board will send a low (0 volt) signal to these 3 fets so of course nothing happens.

What I would like to know is if I am correct in my above statement?

I have noticed that on the XXXXXX schematic the part of the circuit that controls these 3 fets have been modified to fix this problem so the voltage to the gates on these 3 fets are inverted so when J4 pins 9, 10 & 11 are pulled low the gates on Q 17 to Q 19 respectively are pulled high

If I am correct then I will modify the circuitry on the board I have to correct this problem.

Regards,
Andrew

Andrew.  If you have a solenoid driver board with XXXXXX printed on the board, return it to me and I will replace with the correct board.




hope these photos and link help. the photos are of a space invaders rectifier board and transformer with some modifications on the out put side

http://mirror2.ipdb.org/files/2252/Bally_1980_Space_Invaders_Manual.pdf