(Topic ID: 154753)

Eight Ball Deluxe rectifier TP3 over voltage...Updated with Pics


By DnDPins

3 years ago



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  • 77 posts
  • 14 Pinsiders participating
  • Latest reply 3 years ago by cody_chunn
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#51 3 years ago

If there is overvoltage to the CPU board, you are looking in the wrong place. You want to look at the regulated voltages, not the unregulated voltages.

The CPU receives only regulated 5V from the SDB board. The 5V regulator on that board (Q20) might be having a problem. First - have you done the power and ground modifications to your SDB board?
First read paragraph 4.7.5 here:
http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Solenoid_Driver_Upgrades

Does the Alltek board have a test point for the +5V line? If so, what does it measure (before and after overvoltage indication)?
Easy to guess at the after reading but just want to make sure.
And out of curiosity, measure the 12V (unregulated) input to the Alltek board as well.

#52 3 years ago

Again. I have a very similar issue with my MrMrsPacman - except mine does not work for a bit. Mine goes right to the failure mode upon powerup. I'm not asking for help on mine. I'll figure it out. I'm trying to help with the 8-Ball Deluxe problem - by providing info on what I'm going through. Here is my path toward a fix.

1. Try reflowing the solder on the rectifier board - especially at CR5-8. Your board seems to work for a bit - pointing to a heat issue. Give it a try afterwards.
2. Replace CR5-8 with 6A 400V rectifiers (instead of stock 3A). I too had 56 VDC with my meter on TP3. I replaced mine on Friday - I have a nice much lower waveform from the rectifier board now. One of my rectifiers did fail diode check.
3. Related to 5V regulators on the SDB or Squawk talk - as both take the unreg 12v and create 5vdc. See how long you can run with the Squawk Talk disconnected. This will draw less current through CR5-8. If it runs longer it points to overheat issues with your CR5-8 rectifiers - if you still have the 3A stock ones.

I'm still working on mine, but I do now have better waveforms coming from the rectifier board (using a scope) unloaded. I had noticed before that my 5V regulator on the SDB was real hot when it was working. I'm wondering if my SDB 5V regulator failed and pulled too much current through my CR5-8 and failed a rectifier. (Update: I got mine working. Replacing the CR5-8, reflowing the rectifier board, and replacing the 4A fuse fixed my issue. The fuse was blown after many power up/downs trying to fix the issue. My rectifier board has CR6 and CR7 labels swapped)

I have not done the SDB ground mods. These mods move the ground connections to the SDB board in addition to sending it back through the harness for ground connection on the rectifier board. The mod gives you a better chance of a loss-less ground as you aren't going through 30 year old oxidized connectors. You wind up creating a ground loop - but shouldn't be much of an issue with this type of system. I may install them if I pull my SDB board.

5 months later
#53 3 years ago

Hi All...I am back trying to solve this issue. Funny thing is, I turned the machine on after 5 months of inactivity and it played for 2 days and about 30 games and then again the overvoltage situation. Not that I am surprised since I did not knowingly do anything to fix the issue.

I really want to get this machine up and running now since I am hosting a tournament.

Here are some recent things I have done:
Swapped in known good rectifier board - no change, still over voltage
Swapped in known good SDB - no change, still over voltage
Swapped in known good Alltek MPU- no change, still over voltage
Disconnected lamp driver board - no change, still over voltage
Disconnected sound board - no change, still over voltage

The machine will boot if I unplug J1 from the rectifier board or J1 on the MPU

To me it seems basic troubleshooting tells me the problem is on the playfield but visual inspection doesn't yield anything obvious.

Thoughts?

#54 3 years ago

I dunno. I think of lamps in a case like this. Try removing F1 and F5 one at a time and see if that makes any difference in booting. Since those two busses are exposed under the playfield it's very easy to short things to them.

#55 3 years ago

I have narrowed it down greatly. I removed J3 on the Auxiliary lamp driver board and it boots.

#56 3 years ago

Did you check that the mains side of the transformer is jumpered correctly?

Also, as I said 6 months ago, DON'T get hung up on the unregulated voltages being EXACT. They can read much higher then the "nominal" voltages marked in service manuals - they are a guide only NOT an exact measurement. This is where experience comes in - a tech that is used to working on things like this would use his skills to "interpret" what the meter is telling him.

#57 3 years ago

Thanks Homepin. I did not verify the mains side but since I previously confirmed voltages coming from the transformer, aren't I good with it?

Also, more specifically, it is Both J2 and J3 which if plugged in to the Auxiliary Lamp Driver board will cause the over voltage issue. Does that point to an issue on the board or on the playfield? I guess I should be looking under playfield for issues on the lamps drive by HJ2 and J3. Is there anything on the board which also relates?

#58 3 years ago

What happens if you pull J1 on the aux. lamp driver instead?

#59 3 years ago
Quoted from dothedoo:

What happens if you pull J1 on the aux. lamp driver instead?

With J1 unplugged on the auxiliary board, J2 and 3 are plugged in and the machine boots.

I also tried a known good auxiliary board and it failed to boot with the same overvoltage condition. I guess that confirms something on the playfield...the question is does this narrow my search to something off J1?

#60 3 years ago

Pull F3 on the rectifier, power up and see if you read any voltage on MPU TP5 and aux. lamp driver TP1.

#61 3 years ago
Quoted from dothedoo:

Pull F3 on the rectifier, power up and see if you read any voltage on MPU TP5 and aux. lamp driver TP1.

I get essentially no volts on TP5 of the MPU
I get 6.32 V on TP1 on the auxiliary lamp board

#62 3 years ago

Also perhaps should note that I have the rev b of the rectifier board which has 2 fuses for GI and a 6 amp F3. The schematics I have are for a non LE, does anyone have a link to the LE schematics?

#63 3 years ago
Quoted from DnDPins:

I get essentially no volts on TP5 of the MPU

This is good.....but not what I was expecting. Pulling F3 means no regulated 5V supply so TP5 should be 0V, but I was expecting to see lamp voltage here. You have all connectors plugged in, right?

Quoted from DnDPins:

I get 6.32 V on TP1 on the auxiliary lamp board

Here you have lamp voltage on the 5V test point. TP1 should read ~0V with F3 pulled, so you have a short somewhere on the board. Was J1 plugged or unplugged?

#64 3 years ago
Quoted from dothedoo:

This is good.....but not what I was expecting. Pulling F3 means no regulated 5V supply so TP5 should be 0V, but I was expecting to see lamp voltage here. You have all connectors plugged in, right?

Here you have lamp voltage on the 5V test point. TP1 should read ~0V with F3 pulled, so you have a short somewhere on the board. Was J1 plugged or unplugged?

I did not have J1 plugged in. I will do that and test voltages again with all 3 connectors on the auxiliary board.

Since I swapped in a known good aux board I suspect the problem in in the wiring and not board.

With all connectors plugged into the aux board and f3 removed what should I expect on both test points if the short is in the wiring. I am figuring that since I swapped in known good aux board and still had the over voltage that the problem is not with the board.

Thanks for all your help I hope to resolve this shortly now!

#65 3 years ago
Quoted from DnDPins:

With all connectors plugged into the aux board and f3 removed what should I expect on both test points if the short is in the wiring. I am figuring that since I swapped in known good aux board and still had the over voltage that the problem is not with the board.

With the short, both test points should read 6.32V lamp voltage.

#66 3 years ago

Very interesting!

With all 3 aux connectors I get no voltage on either check points.

With only j2 an 3 connected I get 6.32 on tp 1 and nothing on tp 5. What does that mean???

#67 3 years ago

More information:
With F3 in, and all 3 connectors on the Aux. board:
TP5 has no voltage(once the overvoltage indication lite goes on the MPU) and TP1 on Aux Lamp Driver has 5V

What should I look for to find the short if that is the situation?

#68 3 years ago

Have you repinned MPU connector J4?

#69 3 years ago

No I have not repined any connectors.

#70 3 years ago

I just looked at the Alltek schematics (for rev. L) and I didn't think about the test points being numbered differently. Of course they are. So everywhere I said check MPU TP5 it should be MPU TP1 and TP4.

#71 3 years ago

Did you know that on the Alltek mpu that overvoltage LED lights up also when there is under-voltage?
Start at the rectifier board and test your voltages there. Work your way up the chain.

#72 3 years ago

I had a similar problem on my Skateball It turns out a few wires in one of my connectors was shifted over by one slot. I was sending 43 volts to my GI ckt. luckily I did no damage. It was my mistake when I repinned everything.

It might be worth checking all of the connectors for proper wire order.

#73 3 years ago
Quoted from Enaud:

Did you know that on the Alltek mpu that overvoltage LED lights up also when there is under-voltage?
Start at the rectifier board and test your voltages there. Work your way up the chain.

That's what I was thinking when he was reporting 0V on TP5, which prompted me to ask about J4 and then got me into the investigation of the Alltek test points.

#74 3 years ago
Quoted from Platypus:

I had a similar problem on my Skateball It turns out a few wires in one of m connectors was shifted over by one slot. I was sending 43 volts to my GI ckt. luckily I did no damage. It was my mistake when I repinned everything.
It might be worth checking all of the connectors for proper wire order.

I will double check but don't forget this problem has been intermittent. It worked about 3 seperate times therefore that seems to support the re pin solution.

#75 3 years ago

Rectifier:
With everything plugged in and on:
tp 1 - 7.7
tp 2 - 249
Tp 3 - 17.45
Tp 4 - 6.65 AC
tp 5 - 44.9

MPU: ALLTEK
tp 3 - 8.45
Tp 4 - 48.9
Tp 5 - 21.85
Tp 6 - 5
Tp 7 - 44.7

MPU without j1 on auxiliary board plugged in:
Tp 3 - 5
Tp 4 - 2.8

All other MPU voltages the same.

Does that s seem to be a connector issue.

#76 3 years ago

Bump for some possible help.

#77 3 years ago

The rectifier voltages look pretty good except TP3, but that's an unregulated voltage and can swing wildly yet still be regulated into shape.

I admit I haven't read all the posts, but may I suggest taking a step back?

Locate J5 and J6 on rectifier board (if the rectifier is the same as Fathom; I don't have my 8bd manual handy just now).

Set meter to AC VOLTS 200 volt range:

J5 pin 1 (YEL) to pin 7 (YEL/BLK), and pin 4 to pin 8 =?
J5 pin 2 (RED) to pin 3 (RED) =?
J5 pin 6 (GRN) to pin 9 (ORN) =?

J6 pin 1 or 4 (PUR/BLK) to pin 2 or 5 (PUR) =?
J6 pin 3 (BLU) to pin 6 (BLU) =?

If you have already performed these tests pretend like I posted something intelligent.

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