(Topic ID: 80096)

Frankenstein help!!

By perryd

10 years ago


Topic Heartbeat

Topic Stats

  • 12 posts
  • 2 Pinsiders participating
  • Latest reply 10 years ago by perryd
  • Topic is favorited by 2 Pinsiders

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#1 10 years ago

Going to try this for 3rd time....It has been a few weeks since orig. post. I have had MSF for 4 years, all was working fine until a month or so ago.y MSF machine began acting up...Blowing different fuses at random. Checked the PPB and Power Supply Board in which most of the fuses have been blowing, but I think it might be an issue with the CPU since the PIA diagnostic light stays on.

Below is exactly what has been going on with the machine:

F2 and F5 fuses on PPB board, and f8 fuse blew just above the large blue capacitors on the backbox itself.

Replaced fuses, turned the machine on again and laser kick back coil was stuck on and fried. The tip36 transistor was bad at Q1 on the PPB, others seemed fine. Fuses F9, F6 on the same PPB was blown.

Fixed bad transistor and diode and replaced burnt coil. Also replaced the bad fuses again, and then f7 and f5 on the PPB board blew again and no display came up. One fuse F5 on the Power Supply Board was also blown.

replaced blown fuses for the 3rd time and now, All diag. leds on the CPU stay lit and no coils are activated. Also fuse f7 on PPB board blew as well as f5 fuse on power supply. Replaced all of the fuses again and now the F7 and F5 on the power supply board still gets fried upon start-up.

Took all boards off and bench tested the CPU board with old power supply the voltage at 5v, 12, and -12 were all in spec. and the PIA light does go off on the bench. If this is good on the bench, then are the chips on the CPU board fine?

tested power supply board on the bench and those voltages also in spec., though not under any load from PPB board or DMD. I also replaced the 32volt Bridge rectifier off board that resides in the backbox.

Now upon start up, I had nothing connected to the PPB, just the plugs to all the CPU board and Power Supply board and fuse f5 (4amp that controls 32v. coils) keeps blowing. And again, I have nothing from the PPB plugged in
so the CPU will not boot and all the (3) diagnostic lights are still on.

This is driving me nuts and I need someone who really knows Sega/Data East boards to help me out!
Any suggestions on getting this machine back to order would be most appreciated.

thanks
p

#2 10 years ago

You should be able to fire up the cpu in the game with just cn17 connected. If it fires.... try again with everything connected but cn19, cn12 and cn11. If it does, add connectors back one at a time. This should help norrow down a coil issue

#3 10 years ago

Hooked up CPU and Power Supply Board with just CN 17 connector...Machine now just turns off with all 3 led red lights and the PIA doesn't turn off. No fuse blown and I did connect everything but CN19, CN 12, and CN11.
Does this mean a chip is bad on the CPU board even though it tested fine on the bench??

I still have nothing connected to the Playfield Power Board however.

Just trying to see where I go next....

thanks
p

#4 10 years ago

If the cpu fires correctly on the bench then it should in the game with just cn17 plugged in. I would test to make sure you have a full 5volts at the cpu with it in the game.

#5 10 years ago

Okay now, tested voltages on power board and CPU board with just the CN 17 plugged in and now getting
2.7 volts which is obviously not enough... Also blanking LED is not coming on now. What should I look at next to why the correct voltage is not coming through. I measured the voltage on the Power Supply board and it is getting the same 2.7 volts at the 5v. test point, but the 12 volts is fine. These low voltages would not cause a fuse to blow though, would they??

any more suggestions would be greatly appreciated.

thanks
p

#6 10 years ago

Disconnect the left two plugs on the power supply. These power the display. Something is drawing the five volts down. If voltage is still low, then I would suspect the bridge on the power supply might be bad. Low voltages would not cause the fuses to blow but first thing first we gotta get the cpu back up and running.

#7 10 years ago

I tested the Bridge using DMM to buzz it out and it was fine, however , some say it needs to have load on it to really test it and this may not be an accurate representation of the bridge. Also, these tab style bridge rectifiers are a bitch
to desolder...Any suggestions for getting these off the power supply board without damaging the pad?

thanks
p

#8 10 years ago

sorry perry i was confusing systems (been working on alot of wpc lately). This should help you pin point your 5v problem. check this stuff out and check back. once you get that 5v straight and the cpu fired up. we can try and figure out why you were blowing fuses.

A common fault with DataEast power supplies is no or low +5 volts. Of course without a good +5 volt power supply the game is not going to work!
The +5 volt power supply section is not complicated. Most of the time it's bad (.156" molex) connectors on the power supply board. Aside from that, remember +12 volts D.C. comes from the back box mounted bridge rectifier. Remember this bridge can go open or short, causing low +5 volts or a blown fuse, respectively. If good +12 volts is coming from the backbox mounted bridge rectifier, next check the 2N6057 transistor (replace with a 2N6059). If this does fail or leak, a low +5 volts will be seen. Past that there is a MC1723CP voltage regulator chip too, but this rarely fails.

If all these things check out Ok, now check the electrolytic capacitors on the power supply board. These can leak, and corrode the traces on the power supply board underneath them. This is a more common problem then it may seem!

Low-Power Solenoid Voltage Varistor Z1.
On the DE schematics for the power supply, the 25 vac low-power solenoid line comes from a backbox mounted bridge to the power supply board at connector C1 pin 2 (as about 32 volts DC from the bridge rectifier). It goes thru Z1 on the power supply board, which is shown on the schematics as a "Diac". But it's not a Diac, it's a MOV (Varistor). The MOV will short if more than about 50 volts goes thru this line. This component rarely fails (when it does it usually blows up good), but I thought I should mention it since the schematics are confusing. Note sometimes C8 fails (150 mfd 100v) causing the solenoid voltage to drop from 32 vdc to less than 5 volts.

#9 10 years ago

I know I was getting 12 volts already on the Power Supply Board, just under 3 volts on the 5v. section however.
The .156 molex connectors on the power supply board look good to me physically, no burn or anything. Should I test the voltage going through that connector??

How do you test the voltage on the bridge rectifiers be it on the power supply board or just off the boards in the backbox??

thanks again
perry

#10 10 years ago

http://smiley.tzo.com/pinball/backups/dataeast_repair_guide-index1.htm

This link should help you figure out the five volts. I will check my batman forever voltages today and get back to you

#11 10 years ago

i know how to check the voltages on the boards, I was just asking the best way to test voltage on the bridge rectifiers on power supply board.

thanks
p

2 weeks later
#12 10 years ago

Since the Power Supply board and CPU tested fine outside of the machine, what points would I check on machine for voltages going into these boards. Just want to make sure these are working fine and are not the root of the problem.

thanks
p

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