Bally Playboy - Inoperative Flippers

[Thomast]

Hello, All! Just found your forum, registered and posting my 1st question! I have a 1978 Bally Playboy Pinball machine that I'm in the process of restoring. I just replaced the MPU board with an Alltek Ultimate MPU Board due to battery leakage on the old board. replaced some fuses and repaired some resistors and everything seems to work pretty well except for my flippers. Occasionally they will work, but most often not. They both either work or they don't....., when they don't restarting the machine has no effect. Not sure how to diagnose the problem? Any help would be much appreciated!

[pinballdaveh]

A relay on the solenoid driver board controls the flippers. See or listen to it pull in during self test and at the start of a game. If it does pull in the contacts in the relay might still be bad. The solder connections on the solenoid driver board and the fuse/rectifier board need to be checked for cracked connections. reflow connections as needed. If the relay doesn't pull in , it's driven by a driver transistor on the board that needs to be checked. If I remember correctly the relay coil voltage is 48v(somewhat uncommon) but still should be available from great plains electronics.

[Thomast]

Thank you, Pinballdaveh! Much appreciate the advice! I fired up the machine tonight and I don!t hear or see that relay on the Solenoid Board doing anything at all. The repair manual I have says to 'ground collector of transistor Q15 at metal tab' to see if relay K1 pulls in. Can you tell me how to do that? I'll also pull the board and check the solder connections like you said and see what I find! Thanks again for your help! Really appreciate it!

[pinballdaveh]

The driver transistors are the black square components with a metal tab sticking out of the tops of them. Using a jumper wire with clips on ends or a small length of wire with stripped ends, clip one end of wire to the braided ground wire that connects the head to the body. Use the other end of the wire to touch the tab of the proper driver transistor. Some driver transistors will operate coils and some will send signals to the sound board. Do not ground driver transistor tabs for more than 2 seconds as over heating of solenoids may happen.

[Thomast]

Hey, Dave,
I just grounded the black transistor Q15 and I can see and hear the relay engage. I'm also hearing a note played like on start-up. I can engage the flippers when I quickly ground out thr transistor, but then they quit working again in just a few seconds. I pulled the board and the solder connections look to be good. Does it sound like the relay is my problem and may need to be replaced? Thank you again for all your advice! Very much appreciated!

[pinballdaveh]

It sounds like the relay is still ok. Next 2 connectors need to be checked. On the mpu board, j4 pin7 wire. And on the solenoid driver board j4 pin8 wire. Both connectors should be right side lower on each board. Pin1 is at the top of the connector counting downward. With the machine on and a new game started, wiggle each wire connection and see if the relay pulls in, if it does the wire connections are at fault, and need to be repaired. If the relay doesn't pull in , components of the driver circuit need to be checked or possibly replaced. That will require a DMM and soldering equipment.

[Thomast]

Hey, Dave! Well, with your guidance, I believe I have finally found the problem! Looks like it's a bad connection on the MPU Board on that J4 Pin 7 connection! Also looks like I may have burned out my right slingshot solenoid in the process. It energizes immediately when I turn the machine on and stays kicked out till I power off. Does that sound correct and it will need replacing now? Also don't have my displays powering up now, but found a blown fuse in the F2 position on the Rectifier Board. Almost there I believe! Couldn't have gotten this far without all your help and I certainly do appreciate it!

[Coil_Smoke]

Originally Posted by Thomast

looks like I may have burned out my right slingshot solenoid in the process. It energizes immediately when I turn the machine on and stays kicked out till I power off. Does that sound correct and it will need replacing now?

Sounds like the solenoid is still working OK. Designers expect flippers to be activated for extended periods. With the End Of Stroke circuit working, your coil should be spared the dreaded coil smoke!

[pinballdaveh]

It's possible that battery corrosion tracked its way over to j4 on the old mpu working its way into the female plug. J4 has all the solenoid signal wires that the solenoid driver board decodes to fire each solenoid. So if the flipper relay connection is bad , other connections may also be bad. Repining of j4 female .100 pins needs to be done.

[Thomast]

Dave, I neglected to mention that the MPU Board is a brand new Alltek, so hopefully I should'nt be having any board related issues. But you think something on the MPU J4 connection is causing that solenoid to fire immediately upon turning the machin on.....?
Thanks, Tim

[pinballdaveh]

Usually a stuck on coil when the machine is just turned on is it's driver transistor has shorted. And not data or signal wires related. Has the flipper relay and display problems been solved? Using schematic find which driver transistor operates that slingshot, and using a DMM on resistance range, test the resistance of that driver transistor compared to the driver transistor next to it. You mentioned in your 1st post that a new mpu was installed.