Tech:Help me get 5 VDC back on Frankenstein

Black Matrix

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Hey all,
Here's the skinny. I bought this Frankenstein pin and its driving me apeshit. The power supply board basically works like this. AC voltage feeds from the transformer and gets split to + and - 12 volts DC by the bridge rectifier. I HAVE BOTH + AND -12 VDC so the bridge should be fine. The +12 feeds the 5 volts. It goes into a transistor (TR5) which is a 2N6057 and is regulated by an MC1723CP (IC1) chip. My output is currently .1 VDC. I have replaced the transistor, and regulator. I tested all the remaining resistors, fuses and diodes and all appear to be good. I re flowed the solder on the CAPS which I believe are filter caps. I can't figure out why I am only getting .1 volts and I was hoping someone had run into this before. I'm stumped and at a loss.

You can find the manual at this site:
http://files.flipperspill.no/Support/Pinball/Pinball_Manuals.htm

and its page 81 if anyone wants to take a look at it. I will start replacing resitors, diodes and fuses next, but like I said, I'm stumped and I'm at a loss. Looking for suggestions and things to try.

Thanks in advance
 
Maybe this:

"While the power supply is out of the game, always replace cap C2. It's located just south of the power supply heat sink, and if it's bad, the game will have low or no +5 volts. On this game it was DEAD. As in the electrolyte from the capacitor was leaking all over the circuit board! Replace with a new 100 mfd 25 volt cap."

From another repair site.

RM
 
Assuming you're using power supply board #520-5047-03 (mine actually had a #520-5047-02, which Stern told me should also work fine), and TP 3 (+12) and TP 4 (-12) check out, that would indeed seem to confirm your bridge is good.

If you've ruled out the VR, and swapped the IC out as well for grins, check C7 perhaps to verify it's not shot. Wouldn't hurt to look at C11 through C14, but if your +12 is solid, I'd think they'd be ok.

May want to take measurements a component at a time downstream from the VR to see how things look as well.

Usually the bridge, bad connectors (burnt or cold solder), but since you've covered that and the resistors/diodes downstream of IC1 check out as noted, I'd start with that cap (C7) I think.

Let us know what you find!
 
Hey all,
Here's the skinny. I bought this Frankenstein pin and its driving me apeshit. The power supply board basically works like this. AC voltage feeds from the transformer and gets split to + and - 12 volts DC by the bridge rectifier. I HAVE BOTH + AND -12 VDC so the bridge should be fine. The +12 feeds the 5 volts. It goes into a transistor (TR5) which is a 2N6057 and is regulated by an MC1723CP (IC1) chip. My output is currently .1 VDC. I have replaced the transistor, and regulator. I tested all the remaining resistors, fuses and diodes and all appear to be good. I re flowed the solder on the CAPS which I believe are filter caps. I can't figure out why I am only getting .1 volts and I was hoping someone had run into this before. I'm stumped and at a loss.

You can find the manual at this site:
http://files.flipperspill.no/Support/Pinball/Pinball_Manuals.htm

and its page 81 if anyone wants to take a look at it. I will start replacing resitors, diodes and fuses next, but like I said, I'm stumped and I'm at a loss. Looking for suggestions and things to try.

Thanks in advance

I tried to take a look at this but I don't see the power supply schematic in that manual. Am I missing something?
 
I tried to take a look at this but I don't see the power supply schematic in that manual. Am I missing something?

Sorry,
I have the actual manual and my internet was too slow to download it. But in the manual, Page 81 is the Power supply schematics and board layout. I just assumed they were included in the download but if it stopped at Page 67 or less, the schematics wouldn't be included.

So far tonight, I have replaced all the diodes, and C6. I will have to dig up a C2 and C7 and replace it tomorrow. I should be able to put it back in by late Saturday and report back. If you guys have any other ideas, shoot em across. I was about to think it was the caps, but was almost ready to give up and just send it off to be repaired. I'll try these and let you guys know. Thanks.
 
Last edited:
Here's hoping it's bad caps. They are fairly easy to replace and are cheap.

Good luck.

<Robert DeNiro>
"FRANKENSTEIN !!!!!!"
</Robert DeNiro>

RussMyers
 
EEETTS ALIVE!!!!!! in my most maniacal voice. Thanks for all the assists guys. 5 volts DC has been restored. Pin boots. Now I just have to run down why some of the solenoids aren't working and why the flippers won't flip likewise. So I think I'm in the home stretch. Just got to get the manual out and start testing things. Check to see if I have a bad fuse somewhere. That would be awesome. May be playing before the weekends up. Thanks again guys.
 
Done some testing today. For what its worth, On the PPB, I have a bad Q1, Q2, R19, R18, D22 and blown F5, F3, and F9 fuse. I think I had a missing F5 and when I replaced it, I think it blew the F3 and F9. I tested some solenoids and found the Laser kicker on the left side was shot with a melted plunger in it. Oh well. Time to get up another parts order and start on the PPB.
Later.
 
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