Bally SS all coils lock on when powered on?

[ddstoys]

Hi guys working on the Bally strikes and spares I won on eBay I've rebuilt the rectifier board and installed an Altek CPU but at power on all the coils fire and lock on?  

Ive tested all the driver transistors with a multi meter before I ran out of time.

    Any suggestion what to test?   After I've finished cooking tea?

[Ballywannabe]

I would suspect the Solenoid Driver Board.  I had one with a socketed decoder chip (the big one) and the chip became unseated while I was working on it.  When I put the board back in the machine all coils locked on.

Happy hunting!

cheers
Ian

[ddstoys]

Thanks Ian sadly none of these ones are seated .   Back to the workbench

[Strangeways]

I would suspect the Solenoid Driver Board.  I had one with a socketed decoder chip (the big one) and the chip became unseated while I was working on it.  When I put the board back in the machine all coils locked on.

Happy hunting!

cheers
Ian

+1

That would be my first guess.

I assume you have all the correct voltages out of the power supply board and you have 7 flashes on the Altek ?

Check J4 on the SD board . Maybe give the connector pins a light sand.

Can you remove the SD board from the Paragon to test ?

[Retropin]

Somewhere you have a path to ground that is common to all your solenoids..... no doubt its on the driver board... i would be testing decoder chip(s) and connectors for shorts or solder splash on back of board

[Homepin]

This era of driver board has a most idiotic earthing arrangement where the main earth is taken back to the power supply board and then returned to the driver board.

I would be locating that and soldering a solid link onto the driver board. This mod is covered in Clays repair guides 

[chris288]

Dan, I would strongly suggest that you do all the necessary ground mods etc ( as described in the Marvins guide ) as well as checking those other things.

I recently had some voltages on a Bally power supply board that were much lower than they should have been, so I rebuilt it and it turned out that something on the solenoid board was dragging down the voltage on the power supply board. Did the Marvin mods and it fixed the problem. Its possible your problem could be related to this.

If you dont have a spare solenoid board, I can send a modded one over to you as I have a few spares.

[chris288]

This era of driver board has a most idiotic earthing arrangement where the main earth is taken back to the power supply board and then returned to the driver board.

I would be locating that and soldering a solid link onto the driver board. This mod is covered in Clays repair guides 

Beat me to the punch