assistance on next path for stuck on lights - baby pacman

beerorkid

New member
Joined
Oct 19, 2009
Messages
763
Reaction score
6
Location
Lincoln, Nebraska
assistance on next path for stuck on lights - baby pacman

Got a baby pacman a bit ago and am working on getting all the lights on the playfield working. I replaced a lot of bulbs and have found an issue with two lights that are wired together that remain on at all times.

From reading over the pinrepair page on BPM it seems I must have a bad transistor (think that is the right terminology)

The AS-2518-107 lamp/solenoid driver board often has problems. Most often the 2N5060 SCRs fail causing non-working or locked-on pinball playfield lamps. The 4514 lamp decoders (U1,U2) usually don't fail though. So if some playfield lamps don't work (and its not the bulb or lamp socket), suspect a 2N5060 SCR on the lamp/solenoid driver board connector. Note the color of the wire going to the problem lamp socket. Then find this wire color on the lamp/solenoid driver board connector. Then trace the connector its corresponding 2N5060 SCR. The lower leg of the SCR can be grounded, and the playfield light should turn on. If it does the wiring from the SCR to the playfield lamp is good, and the 2N5060 SCR should be replaced.

Also the SE9302 transistors (TIP102 replaceable) and CA3081 pre-driver (U3,U5) chips can fail causing locked-on or non-working solenoids. The solenoid drivers are decoded by a 74LS138 chip at U4. Also on this board is the +5 volt voltage regulator at Q41 and a 11,000 mfd filter capacitor at C2. This supplies power to the -133 MPU board. Often the C2 filter capacitor needs to be replaced.

I am thinking it must be a 2N5060 that is causing the problem on the lamp/solenoid driver board causing the issue.

I looked over the manual. Link (hosting it myself for faster DL) and it does not seem as informational as the ones for my other pinballs. I cant seem to figure out which transistor it might be that corresponds to the lights messed up.

The 2 and the A I am pointing at in the 2nd row are the ones that stay turned on constantly.

4186102853_c4d0205f68.jpg


bottom view

4186867802_46d0b8ec11.jpg


Lamp board. (can get better pic if needed. Pretty much just throwing them out here for the hell.

4186109625_515b159829.jpg


Higher res pics: http://www.flickr.com/photos/beerorkid/sets/72157607200160470/

If I pull the board out how can I test the transistors to see which one is bad with a DMM? If you could assist me how to go about finding that information it would be extremely helpful. I am not too DMM or reading schematics savy. Could it be the little diodes (once hope my terminology is correct) on the lamp sockets themselves?

I am ready to start doing this work myself and hope you can give me a few ideas.
 
Last edited:
Last edited:
Thanks Lindsey. Looks like I have some reading in my future.

after skimming that it seems the schematics will show which one it is and how to test.

Will update when done.

Trying to figure out as much as I can before I ask for help. Glad I found this place.

I did not take pics of it, but one of the drop targets where the captured ball gets hit had some paper taped in there and made the drop target stick up. No clue why someone did that, but it seems way before troxel had it from the age of the tape. Baby is going to shine here soon.

Thanks again. Saw your edit.
 
Last edited:
Steve, if you want any on-site troubleshooting assistance, just drop me an email. Always happy to help.

Amos

Thanks man. Gonna see what I can figure out sometime. seems radio shack does not carry that 2N5060, but I need to place a small order anyways. Noticed a broken flipper :(

My arm looks hairy in that pic. I feel quite manly now ;)
 
i replaced a few of those SCRs on my baby pac. All you gotta do is do like the guide says. Look at the color of the wires going to each lamp. Find the connector that has that same color wire. Note which pin of the connector that the wire goes to. Now trace it up to the corresponding SCR. Replace SCR.

You will probably have to pull the board so you can follow the trace on the backside.

Really only takes a few minutes to replace them.
 
i replaced a few of those SCRs on my baby pac. All you gotta do is do like the guide says. Look at the color of the wires going to each lamp. Find the connector that has that same color wire. Note which pin of the connector that the wire goes to. Now trace it up to the corresponding SCR. Replace SCR.

You will probably have to pull the board so you can follow the trace on the backside.

Really only takes a few minutes to replace them.

Nice. I know the two wires and which connector they are in. Was thinking that would be my first way to figure out which one it was. Thanks for the tip.
 
Replace the SCR at Q24.

Edward

So finally got around to this almost 8 months later. With my limited knowledge of WTF I am doing I tested All the SCRs and Q24 seemed bad. The issue I am trying to fix is still there though. if both lamp sockets have bulbs in them they both stay on and are 2X as bright as they normally would be. If only one lamp socket has a bulb in it, the lamp works as it should. Something must be connecting the two lights and causing a problem. These are the smaller 2N5060 SCRs so they should only control one light. I replaced the SCR and the issue was still there. I turned off the machine and tested the SCR again and it seemed fine.

Going to try and provide as much information as I can.

I was using the guide Lindsey posted. http://www.pinrepair.com/bally/index3.htm#lamp

How I tested the SCRs
On my DMM I used ohms setting and connected the C and G. Then I switched to the diode setting and got better results testing C and G again. Set to diode most SCRs would show .66X and on the one I replaced it was .006 That is what I based my checking on. All others were at .66X so I figured they were good.

This pic shows a 2N5060 circled in purple.

4852902641_d0c034aaf4_o.jpg


here is a schematic of them

4852809005_c3677bc1d2_o.gif


My DMM

4852808969_622f1b497b_o.jpg


Here is a pic under the playfield. The purple arrows make it just a bit more clear which sockets are having the issue. The green is a wire that runs between them both.

4853538906_31261fd6d1_o.png


Seems all the lamps do have wires running to another and then their own wire that must go to the SCR. Is it possible that the diode on the lamp socket is bad? There is one wire that is still connected, but by only a few strands which I will attach better. Just wondering where to go from here.
 
Last edited:
Sounds like you have a bad socket or diode on the socket itself. Remove one leg on of the diode from the socket and test the diode via your multimeter. I'd start with the dimmer socket. If the diode(s) are good, suspect the socket. You'll need to replace it and resolder the ground braid.
 
Sounds like you have a bad socket or diode on the socket itself. Remove one leg on of the diode from the socket and test the diode via your multimeter. I'd start with the dimmer socket. If the diode(s) are good, suspect the socket. You'll need to replace it and resolder the ground braid.

I agree. I think it's a shorted diode or diodes on the lamps. Here's why:

It's important to note that Baby Pac-Man and Granny And The Gators use a different MPU than the other Bally pinball machines. There is only one component different between them but that one component made a pretty huge difference.

The difference between the 2 systems is the -35, -17, etc... MPUs generate the zero cross detection from the solenoid voltage (rectified, unfiltered 43VDC). The -133 MPU generates the zero cross detection from the AC switched illumination voltage (6.5VAC) going to the playfield. It's important to remember that there is AC (unrectified) switched illumination voltage going to the playfield in these games. This is a departure from the old system of rectified but unfiltered DC switched illumination voltage going out to the lamps.

It's also important to remember that there are 2 voltages called "switched illumination" on the schematics. One is the conventional switched illumination and the other is straight AC going to the playfield. I'm not sure that the original switched illumination voltage is even used in the game but it's present on the schematics.

With this change the MPU -133 can not only tell when the AC is crossing zero like the -35 but it can tell whether it's about to swing positive or negative as well. Now you can connect 2 lamps to each SCR output with a diode in series with each lamp and one lamp connected to each side of the 6.5VAC tap on the transformer and drive each lamp individually through software. One lamp can be energized on the positive swing of the AC and the other on the negative.

They doubled the number of lamps they could control. Pretty brilliant actually.

Now you can see how a shorted diode could cause this problem. The lamps are both being turned on twice as frequently as they should be so they're brighter. Quite an interesting problem and a good excuse to explain the difference between the -35 and -133 pinball systems :)
 
Last edited:
Awesome. Thanks rcranetx and Lindsey. I was hoping if I provided enough information it would help one of you assist. Been looking up how to test a diode online and have a grasp on your reply. It does make sense and explains how they are doing two lights on one wire now.

Going to read through the manual BPM page at pinrepair to figure out what diode to pick up as a replacement. Doubt radio shack will carry them, but I need to place an order at pinballlife anyways.

Thanks for the tips. Will reply when fixed.
 
Last edited:
Awesome. Thanks rcranetx and Lindsay. I was hoping if I provided enough information it would help one of you assist. Been looking up how to test a diode online and have a grasp on your reply. It does make sense and explains how they are doing two lights on one wire now.

It was quite a revelation when I discovered how this works. Happy to share the info.

Going to read through the manual BPM page at pinrepair to figure out what diode to pick up as a replacement. Doubt radio shack will carry them, but I need to place an order at pinballlife anyways.

It's just a diode blocking a pretty low voltage. Pretty much any old diode (1n4001-1n4007) will do the job but if you're buying diodes you might as well go for something like a higher voltage rating. You might want to use them for something else and the price difference should be negligible. I'm sure Clay (pinrepair) suggests something specific in his guide. Go with that if they have them at Radio Shack. I'm sure they will have basic diodes.

EDIT: The schematic shows 1n4148 diodes (100v 200ma). Those are some pretty crappy diodes. I would go with what I've suggested above.
 
Last edited:
EDIT: The schematic shows 1n4148 diodes (100v 200ma). Those are some pretty crappy diodes. I would go with what I've suggested above.

Damn Lindsey you rule. Was searching through the manual and not having much luck. Went and looked at them over lunch and could not find a number on them, but they look like the 1N4148 ones. I will pick up some beefier ones tonight.

Thanks again for the help.
 
All of the lights are working now :)

That was the first time I have soldered on my own board and it was fun. Saw a few 1n4001 on other lamp sockets. Re flowed a connection to the braid on another set to get them all working. The lamp board had a ton of work before I got to it. The others have been worked on as well.

Thanks for all the help.
 
With this change the MPU -133 can not only tell when the AC is crossing zero like the -35 but it can tell whether it's about to swing positive or negative as well. Now you can connect 2 lamps to each SCR output with a diode in series with each lamp and one lamp connected to each side of the 6.5VAC tap on the transformer and drive each lamp individually through software. One lamp can be energized on the positive swing of the AC and the other on the negative.

They doubled the number of lamps they could control. Pretty brilliant actually.

Now you can see how a shorted diode could cause this problem. The lamps are both being turned on twice as frequently as they should be so they're brighter. Quite an interesting problem and a good excuse to explain the difference between the -35 and -133 pinball systems :)


Yup, confuses many a tech the first time they work on one of these (or the later 6803 platform). One SCR controls two lamps....separately. Definately brilliant at the time!

Edward
 
While still troubleshooting this machine I figured I would just keep this thread going on a diff issues I am running into.

So I decided to replace all under plastic lights with frosted white LED lamps. I spent a bunch of time working on this which was a huge pain because the lamps are so close and all those diodes are soooo sharp. I am bloodied and bummed. Some of the LEDs will not light. Some I could get to light by turning the bulb around, but some will not go at all. If I put in a regular 555 they light no prob.

I am going to try and swap out the diode, but was wondering if anyone else has any suggestions on why this is happening.

The LEDs look so amazing on this old machine so I am happy I decided to go that way.
 
Been rocking some games on BPM lately. Got a few new high scores. I think it might have something to do with how I straightened out my flippers. Sems in most pictures I see of this game and how mine came that the flippers are angled way down and below the line from the lane. I have them pretty much in line now, but it does seem to make it harder for the ball to eject from the drain. Game play has improved so much with the new flipper angle though. I am prob in the wrong, but like how it is set up currently. You can see pics at the bottom of this page with the flippers in different configs.

The issue I am having
Getting closer. Messed with the LED bulbs some more and ended up putting reg 555s in those sockets that will not light with a LED so I can play. I even replaced some more SCRs and Diodes while troubleshooting, but some lamp sockets still not work with a LED. While reading the guide for Bally games I found something I think might have something to do with it.

Dim CPU Controlled Lights and the SEB.
If all your CPU controlled lights are dim, this can cause problems with the Solenoid Expander Board (SEB). For example if the SEB relay "buzzes" instead of "clicking", that's indication of a problem. If the CPU controlled lights are dim, I highly suggest replacing the 6 volt bridge rectifier on the transformer's rectifier board. On pre-Xenon games especially, dim CPU controlled lights can be caused by an over-stressed and failing 6 volt bridge rectifier for the CPU controlled lights. Always use a 400 volt 35 amp bridge as a replacement. With a good strong 6 volts DC, the SEB will work better (and all your CPU controlled lights will be brighter too).

The lights were really dim before I put in the LED bulbs. Some stronger than others, but most pretty dim. I do not think I have a SEB, but there is at least one bridge rectifier on the rectifier board. Would that be something I should check, or am I going in the wrong direction?

I am also going to check the header pins on my board for the lights for weak solder.

BPM manual link if needed.
 
Have you tried turning the 555 LEDs 180 degrees in their sockets? Most LEDs will have a polarity and will only work in one of the two possible positions you could insert them.

Beyond that I would think that if an incandescent lamp will light in the socket you can make an LED turn on one way or another. I would be curious to see if all of the LEDs that are not working are on one half of the AC or the other. Which lamp sockets will work with incandescent lamps but not LEDs?
 
By flipping them 180 I was able to get a bunch of them to start working except for a few stubborn ones. I even flipped the leads on one LED to check, thinking the holder might be cracked like what happens with some fuse holders. Was a long shot and did not make a difference.

I will take a look when I get home in about an hour and see which ones are not lighting up the LEds.
 
Back
Top Bottom