You could have a little AC ripple from the 48+ volt bridge.
Spiking is definitely coming from the flippers.
You could also have a bad flipper diode.
I would try/test the flipper diodes 1st.

Future Spa, KISS, and Space Invaders use a unique power supply to these three games. This may have something to do with it. I think everyone so far is spot on from my experience. The little flicker does occur on pretty much every Bally to one degree or another. I'll let the engineer types chime in but I'd bet that the multitude of windings in the transformer to derive the different voltages plays a part. When the draw from four flippers happens on the +48v line, the emf puts the 7.5vac GI string sine wave out of kilter. Add that LED's are for the most part off or on, whereas incandescent filaments take a while (milliseconds) from cold to glow. Probably exacerbates the issue on this Future Spa. Anyone with a scope want to see what the 7.5vac GI line looks like when four flippers are energized?

Care to elaborate on the blacked out score windows?

I have an Eight Ball with incandescent GI and I see the same effect. I also have a Future Spa and it behaves pretty similarly with LED GI. LEDs are current driven so they will dim with current changes, but without the same delay as a regular bulb. The GI winding is AC output and not regulated so very brute force design. I am not sure there is much you could do to change it. I also have a Xenon and a Flash Gordon and both have the bigger transformer in the cabinet with the rectifier board next to it. They do this a lot less. I suspect Bally beefed up the 6.3VAC winding on the transformer, maybe the old one was near its saturation point.

They aren't blacked out. The game is just off in the photo.

Is there no way to use capacitors or some kind of capacitor circuit to solve these kinds of problems?

Simplest thing to do is use a separate AC power supply and connect the GI to it. You could use a DC power supply which is likely easier to find since the GI circuit doesn't care if it is AC or not.
After doing all that I suspect there will always be some subtle effect from the flippers.

Does this sound like a PCB problem? Paragon boots (7 flashes). Put a quarter in and game racks up a credit. Credit button starts a game but none of the switches add points, no sounds, and no solenoids fire. It's like everything is dead. If I run the self test the lights flash, displays work, and the solenoids all fire. Any ideas?

Is it the playfield switch connector that feeds into the CPU?

Yeah sounds like your playfield switches are all unplugged or otherwise not registering

I didn't notice before, but the tilt light comes on after i start a game, and when I perform the self test, the tilt switch (one of three) is shown activated. Visually the switches are all open. I tested the diodes across the switches and they test good. The cap across the plumb bob doesn't appear to be shorted. What am I missing?

Have you checked all the tilts?
There's the plum bob, ball roll, coin door slam, and under-playfield slamp.

-Hans

Yes, checked them all. Also checked at the MPU for closed switches and found none. Wondering if I am not checking something correctly? I checked across A4J2 pins 1 and 14. Checked across A4J3 pins 3 and 16, then across pins 2 and 15.

Could it be the capacitor on the tilt?

Yep! That was it! I checked it for shorts deenergized and it was ok, but when energized it conducted. I cut it out and game works!

I think I fixed this. There are no caps on the rollover buttons. There are some on the 5 switches for the star inserts. When inspecting things I found a diode on one of those 5 that had one end pop free very easily when given a slight tug. On another it was already broken free and the other side was spinning freely, but snugly held inside the hole of the switch tab. Re-attached these 3 leads securely and tested a bunch of times and no free 500 point events happened.

Anyone have any recommendations on how to get rid of the yellow discoloration on the early Bally SS white chime boxes (is it even possible)? I've got my tilt board apart and decided to clean up the chimes in a Bally Black Jack. Ultrasonic cleaner took years of dirt and grime off of all the parts, and now I'm tumbling the metal bits over the weekend. I've got a chime rebuild kit for when things are ready to be re-assembled.

With the dirt and grime gone, the white chime resonance boxes show yellow discoloration. I've tried scrubbing with Mean Green and other cleaners, as well as Magic Eraser, and even tho I didn't expect that to help with the discoloration it did improve it slightly.

Can the discoloration be eliminated/further reduced somehow? Painting it doesn't seem like a good idea.

IMG_7281 (resized).jpg

Peroxide & UV method seems to be the way for this problem. Plenty of info on the net about it.

http://www.retrofixes.com/2013/10/how-to-clean-whiten-yellowed-plastics.html?m=1

Retrobriting is the way to go. Use liquid hydrogen peroxide over the paste.

Isn't there a new MPU replacement board out there that custom ROM can be used with? Alltek are definitely out, and so are Weebly board right?

This one? https://pinside.com/pinball/forum/topic/mypinballs-custom-pinball-controller-for-ballystern-games/

Check w barakandl but the weebly mpu's do have an extra socket to run external roms

Yes, @barakandl's replacement Bally/Stern MPU board has a socket for an optional 27512 ROM that gives you 61k bytes of usable ROM space (up from the standard 8k bytes) and also increases the standard RAM size from 384 bytes to 3968 bytes.
If you're writing custom code you won't have to worry about running out of ROM/RAM space.

No other after market native 6800/6802 MPU board offers these expanded ROM/RAM features.

Able to coach me on this? QUENCH? barakandl? others?
https://pinside.com/pinball/forum/topic/bally-2518-17-led-locked-on

ok so that was the only one i found as well:
https://pinside.com/pinball/market/shops/1055-nvramweeblycom/01281-new-universal-bally-stern-replacement-mpu-

I was just worried it wasn't going to be a straight pass through of custom ROM since there is only one socket (You know that cool Bally ST custom ROM comes in 2x 2732 chips )

Bally viking... cane with a NGS sound ROM installed. Had a new ROM burned and the center saucer isn't making a sound, but the speaker does make a little "pop" when the switch is activated. Bad rom, or is there another likely culprit? Replaced all caps and reflowed the sound board.

Hey guys, I have a Bally Sounds Plus (AS-2518-56) board out of a Xenon that I'm having a hell of a time with... I'm seeing the below and am relatively stuck on where to go next...

SYmptoms - no sounds (or vocals)

1 - Took the board out - Cap kit was done prior to my involvement (looked new and correctly connected)
2 - repinned the connectors and replaced the POT
3 - Voltages are 13.6 and 5.17 on 1 an 2 (14.9 on 3, 3 on 5, and 13 on 6 if that matters, but I believe the 5v and 12v are the keys)
4 - Replaced each chip on the board with ones out of my spare MPUs and/or working 51 board (I'm back home testing in my Mystic...)

Still - no sounds. I do hear hum when the playfield lights shift around

Any expert advice on where to go next? I'd recommend just replacing the stupid thing if it didn't need to be that special board to mate with the vocalizer. (and it's for a sweet elderly couple that have had it since the mid 80s, so I'm kinda pro-bono on this one and trying to resolve it in house)

Hi!
Looking for a hires picture of the Bally Playboy backglass. Any help appreciated.

Maybe your program prom(s) are bad/corrupt?

The sound worked for one game session, next tune I turned it on it wasn't there again so it exists on the ROM, any ideas?

Is there any oxidation on the DIP leads for socketed parts? Also what kind of DIP sockets are used? Some are known to be troublesome. I'd also check the headers and the connectors that plug into them.

The chips all look clean, although the sockets that are used are the cheap older kind. The headers were all reflowed. No amount of pressing or twisting chips or wiggling connectors is making a difference.

I use these, just to be sure. Order a few and break off the length you need. Go in easier and more reliably (zero solder bridges in the several jobs I’ve done) for me than full sockets

https://www.marcospecialties.com/pinball-parts/SIP40

Yeah that's what I usually use I just dont want to shotgun them on the 300 or so pins on the sound board! Rainy day project I guess...

Only the lower half of the gi on my Lost World is working. (Yes I know that there are no bulbs in them anymore lol)
Inserts don't work at all.
Anyone got a clue?
Contacts are cleaned.
20191129_212115_HDR (resized).jpg

For the insert lights, this was a really helpful post that taught me how to check individual lamp sockets all the way up to the driver board:

https://pinside.com/pinball/forum/topic/flash-gordon-lamps-flashing-in-unison-when-they-should-be-solid#post-5286660

For the GI, I’m less certain, but perhaps a broken wire somewhere in the chain.

I would also check to make sure the insert lamps are getting power. I believe they are all fed off of a common wire stapled to the underside of the playfield.

Thank you @Nokoro! Will look at those things

I put in 5v switching power supplies for LEDs in the GI. For one flat smooth DC eliminates the 120hz flickering when the AC goes across zero which my eyes perceive as a strobe light effect when the ball moves quickly. It also completely eliminates the dimming of GI lamps when the flippers fire. I have them in almost all my games with GI led and it makes a big difference to me. 5v is still plenty to light up the LEDs and running them at a lower voltage will improve their lifespan and use less current. Usually you can adjust the switchers up to about 5.5v with the trim pot on the power supply.

Because the GI is across earth its not the easiest to install in a bally game. You have to splice into the GI wires after they leave the rectifier board. I add inline plugs so the transformer assembly could still be removed or have the head taken off the game depending on where you put things. Really easy to install in WMS games near the transformer. Remember to de-rate the fuses too. I saw some pictures of an LED melted that burned a playfield.... they can short out.

Do you have a model # or link of what you use?

Last ones I bought where 5v 20a from here.
ebay.com link: AC 110V 220V TO DC 12V 24V 5V 10 20 30 33A Switch Power Supply Adapter LED Strip

I use the 5v 20a cheapies. I bought a name brand (mean well i think) one once and it still was full of Chang / Chong/ ChingXing / Donhpauh generic electrolytic capacitors so I just go for the China special and just massively overshoot the current rating to be safe.

I havent had any 5v power supplies fail in a game, but two 12v ones running LED strips around the house have failed (cheap caps exploded tops). The ones that failed where kind of enclosed in things which may have overheated them. I do have one 12v china power supply that has run 3 years now 24/7 for LED strips under the kitchen cabinets. Its still going on strong and last time i looked at it none of the caps are getting puffy.

Thank you! I'll try this.

Wire the line voltage to be past the cabinet switch so it only turns on with the entire game.

For the switcher V+ and V- connections i pull the PF and backbox GI wires out of the connectors. Add an inline connector and fuse to the GI wires and and connect the GI bus to V+ on power supply and the GI return to V- on power supply. I put a separate 4a fuse in line fuse for each the bacbox and pf lamps.

Some things to keep in mind. The Squawk and Talk uses the GI voltage to make -5v. You would have to run a new wire for that and any other cases that use GI AC voltage that I can't think of. Games using a TRIAC to blink the GI may be a problem too, never tried to wire up one of those.

I also usually leave the cabinet on normal AC GI. Its just the coin slot lamps.

In Williams system 3-11 games its really easy to install. By the transformer there is yellow and yellow with white stripe for GI wires. You just remove those yellow wires from the transformer and connect to the switching power supply V+ and V-.

Here is a switching power supply installed in mata hari. Fork terminals for sw power supply connections. Each run of GI bus is individually fused(1.25a sb) with a sss board. Connectors allow you to separate the head and cabinet without cutting up the wiring harness. I pickup the 120vac from the rectifier board cabinet connector. I can adjust the sw power supply up to 6vdc with the trim pot.

Masking tape flags indicates where the wires were and what they carry. It's a bit messy but could be reversed without looking at the schematic.

I also fused the chime box and the knocker which is not fused like the PF coils are. I think that was an oversight by Bally not to fuse those solenoids as they can burn before the 5a rectifier fuse blows.
20191203_182921 (resized).jpg

That looks like a very clean example - nice steal at $400! Black Pyramid's inline drop target multipliers are reminiscent of EBD from around that same time period....always liked both games.

Under rated game for sure. I have one and quite often get comment that they enjoy it.

People probably see a relatively simple playfield and that puts them off before they play it.

My Dolly Parton was working just fine yesterday and today it's doing something I haven't run into yet. Each digit of the display that should show some info (and maybe even some that wouldn't normally) was showing a "3". It has an Alltek MPU, so I'm hoping that isn't where the issue is, but since it is on all 5 displays I wouldn't think it's a chip on a single display.

Give your connectors the wiggle test. Could be a bad connector or cold solder on your displays.

Or just sell me your dolly at a great loss. Awesome game.

Will do, thanks.

No way, sorry. I really like the simplicity and challenge of this game.