you can also try just one display at a time to rule out a problem display effecting the rest of them. otherwise connector problem at MPU J1 seems likely. also make sure no switches are shorted. you can unplug the switch connectors on the right side of the mpu to see if the display issue clears with them off.

Need some help with an Alltek MPU on Dolly Parton. When I power up both green LEDs go solid green, no blinks. I’m reading it as no 43V, yet the TP for that voltage on the MPU is showing 43V. I don’t get the disconnect. I tried doing the reset with having the dip switches at 01111111 or the other way (can’t remember now) and changing back to Dolly setting didn’t change anything.

Can someone tell me why the ball in play display would move over two digits to the left?

Both Clock Jumpers set properly for Bally (both to the right)? All test points on the Alltek show expected voltages? Was this a working system prior to the Alltek going in? Is this a known good/new Alltek board? This is a 40 year old pin...what are the connectors on the wiring harness like? Have they been repinned?

This board has been in this game for 1-2 years at this point. Everything was working great for quite a while. It blew the 43v fuse at some point on route. I took it home so I could take it apart and clean and re-rubber the game. Changed the fuse and it played great for a few weeks at home. Take it on location, play it 5-6 times and it’s great. Come in the next day and it’s doing this.

Can't start a game on my Lost World.
It does not boot for some reason (not a single flash) and the green led stays on.
All testpoints are getting their voltages and all ic sockets have been replaced and all connectors are cleaned. (It did not fix it)
Also the displays and insert lights stay off.

It's like the machine doesn't get told what to do; broken rom?
Anyone got a clue? Thanks in advance
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Bad 5101 ram chip or it’s socket. Also, could be that the battery has failed and is causing problems.

Those are next two things to check.

Have a spare -35 board coming so I can try and convert my Star Trek board over to conventional EPROM and try a few custom compilations!

Solid LED can also be the reset circuit, look up the test of bridging pins 39 and 40 on one of the chips to verify.

Just set up a new to me Harlem Globetrotters that was working fine when I bought it a few days ago. Now that I’ve moved it it starts a game and kicks a ball into the shooter lane, but then nothing - as far as I can tell no switches register and no solenoids fire. However the solenoids do all reset when I start a game, so I believe this is a switch issue...I feel like I’m missing something simple and obvious. Any ideas? And just to confirm, only 1 ball installed in this game, correct?

Have you checked the connectors for the switch matrix in the back box? Are they seated properly? Does the connector have continuity to the playfield switches when you test it with a multimeter?

Only one ball in the game. Probably cold solder joints, IIRC the lower right connector. Give the mpu connectors the wiggle test and see if you can get some switches to register.

Thanks, didn’t notice the first time through that one connector had been pulled off the board completely by folding the head down. Back in business, thanks!

Not a flash means no program to start.
So, yes rom problems.
Check your solder work again and wire the board to accept 2732 eproms.
Burn new eproms and try again.

Alright, have a controlled lamp driving me batty... I've done the following - any ideas?

1 - replaced socket. Can confirm clipping tab to a neighboring tab works.

2 - repinned connector. Twice.

3 - confirmed connection between socket and wire. Ran a brand new wire just to be safe

4 - replaced lamp board from another 100% working Bally game. Still that same one lamp out in game. (Conversely, other game is working 100% with the other board).

Seems it has to be above that - but given how it all works I can't believe the MPU wouldn't only misfire one single lamp. Any ideas of something I missed before I keep swapping and repinning?

Which lamp in which game?

Strikes and spares has the issue - 2k bonus light (Q29)

Confirming against 18k bonus light (Q29) of a Mystic for reference

Also, MPU is an Altek (was bought new and sold with the game, obv no battery damage)

Q29 goes to J1 pin 1.
That is one of the places most cracked solder joints occur.
Please check the print headers on both boards.

Son of a bitch .. it had perfect continuity and everything, but I reflowed and there it is. I was leery of it being a reflow/transistor issue, that's why I just swapped boards. Very strange both worked just fine without any adjustment or modification in Mystic

Thank you Inkochnito... That's what I get for being in a rush

Lesson number one, always reflow the print headers when a board is out of the game.
Especialy if it is still original.
It solves 90% of the problems.

I'll add that in many cases to get a solid solder connection it helps to remove most if the old solder, clean oxidation and any corrosion off the leads and pads, then reflow with fresh solder.

I hope that someone here can help me identify this Bally test fixture. When I search online all I can find are the dedicated Brown Box testers for the individual Bally boards.

This particular tester looks like it was extremely well built and not just a homebrew unless someone very talented. Inside it has coils for proper loads on the driver board, flipper assemblies and chime boxes. It has 4 7-digit displays of which 3 look like they are very early ones. One 6 digit and a open spot which I think is for another 6 digit display. It needs some TLC but I think this will be worth restoring and will help with board repairs once done. Has spots on top for the MPU, Lamp driver, Solenoid driver, and a sound card.

On the right there is an opening with a bunch of spring loaded pins. My best guess is that there may have been a personality module for the exact game being simulated/tested. It would be cool to locate some of those or at least one as an example.

If anyone has any information on this (docs, pictures, parts, etc) please let me know. I'm really looking forward to cleaning this up and putting it back to use.

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Thanks everyone for your help!

Replaced it and also the 6800 chip but no luck. Measured the battery and it's good.

Sometimes it resets, sometimes it doesn't.. What to do?

I think this is the next thing to do.

Hi all - can anyone recommend the right size pins and a good extraction tool to use to repin a connector on the rectifier board? This is for Flash Gordon, and the board is located at the bottom of the cabinet.

to do just one pin? If you repin the whole connector i usually just use a wire cutter, snip as tight as you can from the old connector, strip and crimp... rinse and repeat, all new and shinny.

The smaller pins on the right of the board are .100 and the larger pins on the bottom and left connectors are .156.

Doesn’t Flash Gordon use the molex connectors? If so, I think those are .84 molex

Just checked. They are the molex pins. Any computer supply store should have a Molex pin removed. I ordered mine from Great Plains Electronics. Ed is good people and helps keep this hobby alive. Big Daddy Enterprises also carries headers and pins. Also good people. Also has an eBay presence

You are correct. I read it as the Driver board not the rectifier board. Thanks for correcting.

update: I realize now that this connector is not plugging in directly to the rectifier board. It connects to the small transformer. I managed to use a very small screwdriver and remove the pin that needs to be recrimped, but I still don't know the proper size. In this picture, the orange wire loops from one pin to another on that same connector. The pin I removed is male, and is the center one of the 3 in a row. Thanks for any help identifying the right size.

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Okay so my Lost World still doesn't boot..
I checked all voltages (all okay), got new cpu eproms and put the right jumpers in, replaced 5101 and replaced the 6800, cleaned all connectors, cleaned all pins and cleaned all ic's.
The led stays on and does not flash once.

Anyone got ideas? (I'm really stuck right now)
All I can think of is the reset circuit, but I don't know how (and what) to measure.

On Bally cpu, it should be 0 then a snap up to +5 volts. Aprox.
*
1) I would check to make sure all data and buss lines have continuity
--- to all components first.

https://www.greatplainselectronics.com/products.asp?cat=92

Thank you vec-tor!
The problem I have is that the game didn't come with a manual, and that the electrical drawings from ipdb are unreadable
So I would need a readable manual or photo from the cpu board drawing first..

Refer to the Playboy schematics on IPDB for a clear MPU board circuit diagram - same board.

That's good news, thank you very much!
I can continue my quest on finding out why it doesn't boot

Have you been to the pinwiki? "Section 5.5.1 LED locked on".
https://www.pinwiki.com/wiki/index.php?title=Bally/Stern

No I have not.
Thank you for the advice!

Centaur at our club seems to be ending your ball randomly when there's still balls on the playfield during multiball. I haven't had a chance to look at it yet. Anything to look for other than funky trough switch issues?

Switch test is your friend. Teach yourself how to use it.

Problem with a -35 board I picked up, perhaps someone can offer a clue before I go digging.

Board will lock up after being on an hour or so. You can play games right after being fired up for the first time. If you hit the credit button during a game and it has been on an hour or so it will lock up.

It will be fine in attract mode (has never stopped working while in attract mode) but when you press the credit button will instantly lock up. All controlled lights go out and displays die. Sometimes the machine will sit there and beep, other times if on long enough do nothing at all. Letting it sit for a few minutes with the backbox door open to cool down will let you fire it back up again.

Looking at the wiring diagram, I wondered if it was a door switch return issue. Triggering the coin switches caused no problem and when I trigger the self test button I was able to step through all test and audits till it went to reset after 011 and it locked up on reboot.

Here is a video showing it lock up when the credit button is pressed. Does not exhibit this behavior when the original board is installed.

No AMI chips are present on the board.

Got a Stern Lightning I am working on... and I also have a Black Pyramid (I think that is the same bally setup isn't it?)

I am sure I will need help on the lightning...

Have you replaced C23?

It would appear from the video that just when it's trying to reset the drop targets, it dies. This is very indicative of C23 failing. It could also happen when you flip both flippers at the same time. Any huge current draw will cause the +5v line to become unstable and the CPU dies.

It's also possible that the bridge rectifier is getting weak and when up to full temperature fails to rectify fully (they become leaky allowing more AC to pass through). Another typical condition with the early power supply boards and small bridges.

The reason for this MPU failing could just simply be that the 6800 in this board is more sensitive to the +5v flux than the other.

1) Brand new bridge board, well brand new a few months ago, new connectors too. Ground mods done. New sound board as well. Major caps on solenoid board replaced.

2) Sometimes it doesn't even get that far starting up if left on long enough you get zero boot flashes. Dead as a door nail till it cools off.

3) If I place a fan on the MPU board so far it doesn't fail at all.

The only time it will lock up is when the reset button is pressed or it is coming out of diagnostics/audits and rebooting after being on for an hour.

Rock solid during play.

I'll try starting a game and walk away from it for an hour and see if it locks. If not I'll play for a few and then hit the credit button.

Started machine, credited up a game, played three balls and let it sit for 45 minutes.

Fired ball four, had a spirited round, ball drained, bonus counted down and machine locked up. Did not even try and kick out the ball.

No displays, no controlled lamps.

Any chance the bridge board is a Rottendog? I've had two Rottendog power boards with failed bridges. Their board construction is fine, but I think the quality of components can be suspect at times. One time the bridge got so hot I couldn't touch it, while the other two were warm but I could keep my finger on them. This was a strong indication that it had failed. Replaced the bridge and it worked fine.

Your problem most certainly does indicate a heat buildup problem. Perhaps it's not the MPU, but the power or solenoid driver board.

Any chance you have a spare game that you could swap transformer/power boards into?

1) It is Rottendog, works fine with first MPU, bridges are cool to the touch.

2) I can swap MPU and problem goes away, I can also leave the backglass off and door open and it gets enough airflow it delays the MPU locking up.

Thought I found the problem- The Hitachi 6821 PIA located at the U11 location. If I wait till the unit locks, shut down and give it a blast of cold air from an upside down container of canned air it reboots instantly. Spraying the other IC's did not seem to have any effect speeding up the time needed to get it to reboot again. I might just happen to have a few in my stash, need to amble out to the workshop and check. Digital temp reader shows no difference between it and the others, maybe getting fussy with old age IF it is the problem.

Edit: No dice on U11 or U10, swapping chips made no difference. Must have been getting something near by as I can get the MPU to reboot instantly with a quick shot of air. I'll pick at it some more tomorrow if I have time after work.

JUST an FYI the only thing on the board that seems to remotely get warm is the transistors located at Q1 and Q5 and even then 90-95F-ish.

Going to try a different set of EPROMs tonight, it has been suggested that one might have a weak flash which I can't say I have heard of but easy enough to do and I have plenty of blank chips and electrons

Burned an earlier revision on 2 fresh chips and its running since 9:30AM, played a few games and now we wait.

Now 11:07AM and still going, just going to let it sit all day and see what happens.