DM flashers not working.

By Turkey_Robinson

4 years ago


  • 37 posts
  • 10 Pinsiders participating
  • Latest reply 4 years ago by Turkey_Robinson
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#1 4 years ago

So I'm finally getting a multi-meter tomorrow which means I can now start diagnosing a few electrical issues I've been having with my machines. I wanted to post this now so I can get some helpful ideas on what to do once I get it.

First up, my DM has no flasher activity at all. I'm assuming I should check some fuses first? The flasher secondary fuse would be my guess, but then again, I'm still learning It doesn't work during test mode either.

I did a forum search for the problem and someone said "It could be the LM339 op amp/comparator or the 74LS74 IC has gone bad in the driver circuit for those flashers." Does that sound like a possibility?



#2 4 years ago

first fuse and connectors

#3 4 years ago

Get yourself a WPC manual. It'll come in handy no matter what WPC game you have. Your regular manual should help you understand the flasher circuit and stuff, but the WPC manual helps you understand the boards.

Until then, check the following on your power driver board (upper right corner)...With the coin door closed, Led 5 should be lit.

The power comes in at J-102 and J- 104 or 105. Check fuse 111. Br-4 & C-11 converts Ac to Dc (you might have a cracked trace on the top side of the board or any of the J connector pins)

TP 7 should be about 20 volts dc. The flashers 20 Volts comes out J-106,7 &8 which are all tied together.

That's the hot side of the flasher circuit and probably where your problem is since none of 'em work.

Good luck!

#4 4 years ago

I do have the manual, which I've been reading over and trying to understand. Right off the bat I notice that LED 5 is not lit. What does that tell me?

#5 4 years ago

No led 5 = no 20 volts = no flashers. When you get your meter, Check the fuse (5 amp slo-blow). Wouldn't hurt to check all the flasher sockets, lugs & wiring too.

If it's blown, replace the fuse & power up. if it blows again, you've probably got a shorted br-4.

If the fuse isn't blown, you've probably got a cracked trace or connector pin (J-102,4,5 or J-106,7,8) on the circuit board.

I'm guessing you should probably find someone local to do any board work if you need it.

pm me if you need to, and I can call you & walk you thru it.

#6 4 years ago

All the flashers in my DM where out when I got it. I played it probably 50 times before I even noticed (how did that happen?). I then rewatched the for sale/trade video and they were out in that too. What was wrong? A fuse was simply too old. It didn't look blown. Actually, it looked fine! I tested it and it was dead. New one = Working flashers.

Great game! I really, really like it.

#7 4 years ago

Alright, So I finally got the DMM and it turns out that the fuse is fine.

So this is where shit is going to get real for me. I'm trying to absorb as much knowledge as I can from various pinside threads and by reading pinwiki which is also a great supply of knowledge but I still really don't know what I'm doing.

Tullster, let's start from the top of your helpful recommendations. Checking the flasher sockets, lugs and wiring. Flasher sockets to make sure the lights are plugged in? To check wiring I'm assuming this means to follow all the wires from the power source to the lamps to make sure that they are indeed connected. not sure what the lugs are though.

To check the connector pins and traces do I need to remove the board to see the backside to visually inspect the connections?

While I await responses I'll figure out how to work this multi-meter Noobs

#8 4 years ago

I took another look at it. I followed the wires from the flashers to the backbox. Everything seemed to be connected as it's supposed to be.

#9 4 years ago

I have seen all flashers out on a game and it turned out that they were all simply burned out. Always start simple. Replace one bulb and test. Since the boards led is also out, the board is probably the problem. But I have also seen those indicator LEDs die. So make no assumptions. These would be your steps:

1) dmm the fuses - all of them.
2) replace at least one flasher bulb
3) if fuses are ok and bulbs are ok start checking power at the board. The circuits here are simple. Input power to fuse, to bridge, to cap, out. If you don't have 20vdc at your flashers with the coin door closed, check for voltage at the flasher connector. If no 20vdc there, test / replace the bridge rectifier and associated cap. Look at traces of these components. Possibly dmm the traces.

Hopefully you get the idea from there.

#10 4 years ago


So if the fuses and the bulbs are fine do I need to take out the board to do those checks?

#11 4 years ago

Well to trace power you need the board installed and running.

#12 4 years ago

Are you checking the fuse for continuity out of the game or with at least one end popped out?

#13 4 years ago

Going by what you're telling us, my hunch is that you've got a cracked trace on the br-4 bridge rectifier or the J connectors (probably on the top side of the board). Wherever/whatever the problem in the circuit is, you'll need to pull the board and follow the circuit with the continuity and/or ohms settings of your dmm. I've given you the area to look, and maybe you can find the WPC power driver board schematics on-line (page 1). It's a pretty basic circuit.

I tend to run jumpers on these boards especially if components have been previously replaced by previous owners of unknown abilities

That being said (and guessing that you might be in over your head), I'd recommend finding a local who's comfortable in troubleshooting and walking you through this (I'd do it, but don't get over your way on a regular basis). OR, if you're adventurous, find the schematics and don't mind the possibility of learning things the hard way.. go for it!

#14 4 years ago

Rascal, I just tried a new fuse with no luck.

Tullster, I'm all in for learning. I took a basic electronics course back in HS but that was 13 years ago now. I'm hoping some of that knowledge pops back into my brain soon. I was at radio shack yesterday buying fuses and I was looking at some neat books on electronics. I was going to pick one up but not for $21. I'll find one used off amazon or something like that. The whole concept of fixing my machines is the other side of the coin to owning them, I feel. I don't have a car so I can't work on that. I just need to take it one step at a time. This, unfortunately is a bigger step than I've taken before. But i'm going to do this. It may take me scouring the internet for a few hours until I feel confident, but I'm going to do this. Hopefully I don't fuck anything up When I get some time this week I'll see what I can come up with and report back.

Thanks again!

#15 4 years ago

I learned about test points today. Everything looks good except for point 7, which from what I partially understand, is what you fine folks have been telling me all along So now I'm think I need to unhook everything and pop that board out to find exactly where the circuit is not being completed correctly, yes? Bridge rectifiers will be what I have my eye on first.

Also, I picked up a couple books on electricity and electronics from the library to help with my learning to help understand what I'm doing.

Thanks everyone for the help too!

#18 4 years ago
Quoted from Turkey_Robinson:


Worked for me twice now so it might be worth it. Rip that board out and test it. Pay special attention in that thread to...

"No flashers worked, no continuity betwixed negative on BR4 with Negative on C11 nor negative to the board ground, even though I was getting a 400-600 (good) reading on both BR4 negatives & positives testing them in diode mode with with their AC legs.
Borygard told me to jumper Negative from BR4 to negative of C11."

Here's a vid that shows how to test BRs if you are not is very easy to do. Do this before you start getting into wacky searches for screwy Lm339s etc etc.

Test the continuity first

» YouTube video

#19 4 years ago

Thanks a bunch! I think I'll do that today!

......Unless I finally get the new Bioshock in the mail first.

#20 4 years ago

Interesting. So I was reading about how there's a link between the coin door switches and the flasher circuit so I tried fiddling with the 6 connectors on the back of the coin door buttons and the flashers popped on! Interestingly enough about 3/4 of them lit up in the pf, only one was actually flashing, the rest just stayed on at full brightness. None in the backbox lit up though. I took a reading at tp7 for 13v, way under the 20 it needs.

I just went back to check on it again and all the flashers are back to not working again along with no LED 5 action.

Should I still go ahead with the gameplan of inspecting the bridge rectifiers and capacitors?

The plastic coating to the lug (that I thought was part of the problem) on the coin door box was melted. I think that means something.

I'd be interested to hear what ya'll think about this.


#21 4 years ago
Quoted from Turkey_Robinson:

So I was reading about how there's a link between the coin door switches

One of them is for high power - coils and flashers.

Be sure it is wired right, and held in tight enough by the flap that pushes it in when the door closes - they get bent or also be sure the wiring harness isn't in the way.

LTG : )

#22 4 years ago
Quoted from Turkey_Robinson:

Interesting. So I was reading about how there's a link between the coin door switches and the flasher circuit so I tried fiddling with the 6 connectors on the back of the coin door buttons and the flashers popped on! Interestingly enough about 3/4 of them lit up in the pf, only one was actually flashing, the rest just stayed on at full brightness. None in the backbox lit up though. I took a reading at tp7 for 13v, way under the 20 it needs.

Should I still go ahead with the gameplan of inspecting the bridge rectifiers and capacitors?

Replace the switch. I had a CP that I was working on with a similar problem (13V and no flash lamps). After checking and replacing everything in the circuit I checked the coin door switch. It had continuity (I had checked it earlier) but as soon as I tried to pass current it would go open. I tested it again by jumpering around it with alligator clips and the flashlamps worked. Replacing this switch fixed the flashlamps.

#23 4 years ago

So I finally pulled the board out and tested the BR's and the caps associated with it. Everything checked out fine. I tested the pins at j101 through 103 for continuity and they worked fine. For the fun of it I decided to test the fuses again and 111 was burned out already. I just replaced it last week. I put another in and most of the flashers came on. TP7 was still testing low at 13V. There was still a few flashers on the left side of the pf that didn't work. The bulbs tested fine. Some of the ramp flashers wouldn't flash though either. They just stayed on and seem really bright. Same with the 3 at the back behind the see-through blue plastic. And then the fuse blew, which I suspected was going to happen.

I'm not sure where to go now. Do I still go for the jumper that THELAW was talking about or do I look into the coin door switch?

Also, how do I test (what DMM setting and how) if power is making it to the specific lights in question that aren't working?

#24 4 years ago

And of the flasher bulbs bad or sockets shorted drawing down power ?

LTG : )

#25 4 years ago

Hey Turkey... You pm'd me, but I'll reply here so others can see it and chime in if I miss anything or any other ideas come up. I don't have a WPC near me at the moment, so I'm going by memory & the WPC manual. Again, It wouldn't hurt to find someone local to help you, but here goes...

Have you made sure all the power driver board connectors are in the correct spots? Also, since you're green, I'd be careful jumping the door switch.

Also, you say that you've got 13 volts. AC or DC? if it was AC, you've got a cracked trace, bad cap or bad BR-4.

Seems like you've got 3 issues going on. Don't get ahead of yourself. You'll need to take a step back & start at the beginning....

J 102,4 or 5 are your AC power in connecters (not sure which of the 3 are used, probably J 102?), so you should be checking continuity between those & Br 4. Meter off the top of the board and not the bottom. Put the board back in with a good F-111 and connect everything except the connector that attaches to J-106,7 or 8. Power up & check out led 5. Is it on? Fiddle with the door switch. Does led 5 turn on & off when you activate the switch? Does the fuse blow? Put your meter on DC, ground the black lead, and with led 5 on, carefully check pins 5 & 6 on J107... They should read about 20 volts DC. If all this stuff seems to check out ok, You've got to check all your flasher wiring or you might have a board issue down around J 122,3,5 or 6. Either way, stop here and check back with us.

That should keep you busy for a while, and I'm sure someone else might have other ideas too. At least it's only the flashers!

#26 4 years ago

Oh yeah, Kbliznick is right, you've got to replace that switch no matter what. I'm 50- 60 miles west of you, and will lend you one if you want to road trip out here!

#27 4 years ago
Quoted from Turkey_Robinson:

Do I still go for the jumper that THELAW was talking about or do I look into the coin door switch?

Well the jumper was only if you din;t have continuity between the negative of the BRs with caps and board. Bascially that would mean the negative trace is broken somewhere, and jumping it would be fixing that...BUT if there's no issue with that contiuity...that won't help.

#28 4 years ago

Thanks everyone!

tullsters right, this should keep me busy for a while!

#29 4 years ago

This is a very informative thread. I don't currently have this issue, but I'm sure I will at some point do I'm glad this thread is here for reference.

Good luck in solving your problem, I'll keep checking on the progress.

#30 4 years ago
Quoted from tullster:

Again, It wouldn't hurt to find someone local to help you,

When you say this, who do you mean?

I think this might be where I'm at.

#31 4 years ago
Quoted from Turkey_Robinson:

When you say this, who do you mean?

Keep your eyes open for Pinsiders in your area that may be able to help or direct you to someone who can.

Or your post here might get some to contact you.

LTG : )

#32 4 years ago

So Turkey, what did you find? Did everything check out ok? Did you change the door interlock switch?

If you're done trying, you could put up a Tech wanted post. If that doesn't work, Paul Reno is your guy. He's on the south side and runs Home Game Room Supply. I know he will get you fixed up.

And one final thought.... Everyone should do yourselves a favor and be sure you have a WPC and/or WPC '95 Theory of operation & schematics manual. It explains everything WPC that is not in the normal manual, and helps solve problems like this. Every WPC game came NIB with one, but for some reason, they seldom follow the game like the game specific manual does. I checked some suppliers and they were out of stock, but there were plenty on e-bay.

#33 4 years ago

not a good day for pinball at my house.

So I decided that getting someone to come look at it is going to be the route I go. I've had Paul Reno's card in my wallet for over a year now. It's time it finally comes in handy. I'm hoping it's not too expensive.

So as I was at work today I got the dreaded text from my girlfriend that all hell was breaking loose. The claw went out of position, the left flipper doesn't work and the game keeps freezing and resetting. Seems that it's a good time to get someone who knows what they're doing to take a look at it.

It just sucks that we haven't even had it a month now and it's already fucking up. The flasher's weren't really a huge problem because we could still play it. Now she's down for the count for a little bit. That's life sometimes though.

I wish I could apprentice with someone. I really want to get experience doing work on these machines. Until then I'll continue reading my books on electricity I got from the library and hope Mr. Reno can get down to take a look. I've heard many good things about him so I know I'll be in good hands.


1 month later
#34 4 years ago

Turkey, did you get your issue fixed? Don't mean to bump a month old thread, but I was reviewing my thread history and remembered I never heard your results.

#35 4 years ago

nope. Called paul reno to come take a look at it. There's a bunch of things wrong with it. He told me to order ribbon cables and I just got them in today. I need to install them and then call him back. We'll see. Fingers crossed!

#36 4 years ago

Well good luck, I hope you get it all straightened out. I hate when something goes wrong on my machine and I have to wait for the results of fixing it. Just bought a Sorcerer that had a bad transistor where the GI lightning would Always be on instead of flashing when appropriate. Someone pointed me in the direction of the transistor but it drove me nuts waiting for one to show up for me to install and not knowing if that was truly the problem.

#37 4 years ago

Thanks for the kind words. BOTH of my machines are down and it's been almost 2 months. At this point they're just taking up space and it's killing me. I bought them to play them. I'm fortunate to have a few different bars in the area that I can just walk to to scratch the itch, but it's so much sweeter just staying at home playing the ones you own. I'm trying to stay positive though.

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