Bally 5500 - Jumping Reels

[jthelman]

I got this Bally 5500 machine with reels randomly changing rotating direction. I did a clear ram using J10 and Press and HOLD the PSEUDO COIN and TEST buttons, while performing the ram clear the reels are bouncing around for about 10 -15 minutes before they stopped and then got the message CH C in the winner paid window. The machine plays fine until I power it down and let it sit for a while then power it back up and the reels would be dancing for around for 5 to 15 minutes. Then the reels will stop, and the machine will play fine again until I power down and come back the next day to play. Power up machine again and the reels randomly changing rotating direction.

I then purchased a new mpu board with new battery and completed ram clear using J10 and Press and HOLD the PSEUDO COIN and TEST buttons. Have same issues with new mpu board, reels still jumping around. Looked at dip switch JW3 switch 7 controls the reaction of the reels (normal or crazy), tried both ways and did ram clears. I then cleaned the reels where the optics are, still have the jumping reels. Does anyone have any other ideas, or do I have another bad mpu board? The ram clear does not help, and reels are still jumping back and forth.

[Trisail]

Best I can come up with looking at the video - the signals to the reel motors are messed up. Almost like the pulses are missing. The stepper motors are driven more by current than voltage.
I would check the connections for the reels and wiring. I doubt the problem is the mpu board, especially since you've tried a second one with the same results. Has the power supply been looked at? Noise from the power supply could mess up the signals. Recap the ps?

[jthelman]

I’m not sure it would be the signal or wiring to the reel motors since it plays fine after the dancing reels stop.  The reels only bounce around when powering it up and it take a while for them to stop. I have not looked at the power supply. Is it easier to recap or just buy another PS.

[Trisail]

I recap PS's so that's the way I go. If you can, it's worth a try. I don't think I have done any Bally supplies...

Looks like just 5V and 12V with a rectified 24V. There is a link with easy replacement supply here in the forum -

http://newlifegames.com/nlg/index.php?topic=1825.0

I know there are other posts about this as I have mentioned other units you can get from Jameco.

The reels should initialize in one direction only and spin to the last position. Even with the crazy setting they should do that 1st.

I would start with a cheap PS replacement and see where that gets you.

With the problem at power up - I'm thinking the voltages are messed up. The caps are supposed to remove AC ripple on the DC voltages and keep it clean DC.

If you have AC ripple (noise) the 5V to the MPU circuits could look like signals that control the timing and addressing. Also, with it getting to point that the machine plays, the caps are suspect as they take longer to get to 'operation' so to speak. When they dry out - which they do over time - they will work fairly well when they are bad given enough time to 'stabilize' - then one day they give up the ghost and the machine/tool won't work, out of the blue. Then the " all I did is just powered it off and the next time I turned it on it didn't work " situation crops up. It's not like the caps actually instantly just died - they were bad or, going bad from pretty much day one. Enough of my rant.

Check the AC ripple if you like. The replacement supplies are inexpensive and easy enough to do.

On the S+ machines - the edge connectors on the MPU board go bad. Like a cold solder joint. I have, and I believe some of the other repair members are having good luck resoldering the reel connection pins to repair the 'reel tilt' errors on those machines. The cold/bad pin connections cause enough resistance to reduce the current to the reel motors that they don't spin right so the machine throws a 'tilt' error. The stepper motors have to be held 'on' (locked in place) all the time or they would 'rotate' on their own. Because of the current draw - the motors are designed to be held in place under a lower DC voltage (less current draw than what's needed to drive/spin them normally) Reduces heat, increases lifetime and saves energy. If you haven't touched one after the machine has been on a while - they get fairly warm/hot to the touch. Actually, marvels like most of the electronics these days that seem to last almost forever. Gotta love improvements and progress. Another rant.... kind of lol.

[jthelman]

Thanks for the info and I'll look into the power supply and let everyone know.

[jthelman]

Thanks to all, replacing the power supply was the issue of the jumping reels and machine works great.