Fuse F104 keeps blowing. Need help please.

(Topic ID: 238417)

Fuse F104 keeps blowing. Need help please.


By Johnnys

6 days ago



Topic Stats

  • 14 posts
  • 5 Pinsiders participating
  • Latest reply 1 day ago by Johnnys
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#1 6 days ago

I really need some help. I am new to the site and new to pinball repair. I had a nice working Bram Stoker's Dracula until recently when the F104 fuse blew. Now Coils 9-16 are a no go. I did find the violet-orange wire melted to one of the ground brown wires in the circuit so I cut and repaired those but fuse still blows. I am new to electronics but have some tools and I have looked everywhere for someone that had the same problem that could help me out but the closest I could find was from 4 years ago and some questions were not answered for me. I am eager to learn pinball repair as I love the game and want to start growing my collection. Any advice would be most appreciated.

PS. If I remove j107 and J127 I can power on and everything but coils 9-16 seem to work ok. Also, I noticed on power on that the 3 LED D19, D20, D21 seems wrong. I read that 1st D19 should come on for a quick second with d21 and then D19 should go off and D20 should blink. Well D19 never comes on but D20 does blink constantly and D21 remains on ok. Just wanted to mention that as well.

#2 6 days ago
Quoted from Johnnys:

I did find the violet-orange wire melted to one of the ground brown wires in the circuit so I cut and repaired those but fuse still blows.

Do you have any photos of the issue prior to and after repair? It might be good to see what was there and what is there now.

If the fuse blows without any of the solenoids actually firing then you most likely have a short to ground in the playfield wiring.

Quoted from Johnnys:

PS. If I remove j107 and J127 I can power on and everything but coils 9-16 seem to work ok.

This doesn't seem to make sense to me. J107 is solenoid power (for ALL solenoids) and J127 is low current drive (solenoids 9-16). If you remove those plugs then no solenoids should work. Can you clarify?

Quoted from Johnnys:

Also, I noticed on power on that the 3 LED D19, D20, D21 seems wrong. I read that 1st D19 should come on for a quick second with d21 and then D19 should go off and D20 should blink. Well D19 never comes on but D20 does blink constantly and D21 remains on ok. Just wanted to mention that as well.

This sounds like D19 on the CPU board is not working.

#3 6 days ago

Thanks Dumbass for the quick response. You are right, with j107 and j127 no coils from 1-16 seem to work,, the magnet motor still works and coils up in the 30's like the castle lock, mist gates, and castle diverter in back of playfield do however still function as do the flippers.

When I plug in j107 and leave j127 off then only 9-16 do not work.

Im running out of fuses so I only tried powering on without j107/j127 hooked up and thats when I do not blow a fuse at F104 which is a 250v 3A SB fuse that pops during the first 5 or 6 seconds I'd say when the machine is going through its testing at start up while both j107 and j127 plugged in...

I really don't know what I am doing but I was curious to see what kind of voltage I was getting out of the j107 pins on the board with power on and the second one that normally connects to the violet-orange power wire vs the other pins since I know one of the other pins powers coils 1-8 that work and pin#2 was at 74.9VDC while all the other pins came in at almost nothing <.5v

I do not have any pics of the before or after but I can take some if needed but nothing looks off, at least not to my newbie eyes.

ALSO- I did move all coils to see if any jammed up and they all moved smoothly by hand.

#4 6 days ago

Actually, I am not even sure if all but 9-16 worked with j127 off. I am sorry.. I think if everything plugged in and powered on f104 will blow and then the game plays kinda but no coils from 9-16 work. I am not sure if the fuse will pop if j127 is off and j107 is connected.... I have been reading so many things about coils, and f104, and j127, j107 from other willaims wpc boards I forgot whats what...my bad.... but I figured if I had someone knowledgeable that could help diagnose this I would go step by step and hopefully figure out if there is a short in the wiring, coils, or backboard.

#5 6 days ago
Quoted from Johnnys:

Actually, I am not even sure if all but 9-16 worked with j127 off. I am sorry.. I think if everything plugged in and powered on f104 will blow and then the game plays kinda but no coils from 9-16 work. I am not sure if the fuse will pop if j127 is off and j107 is connected.... I have been reading so many things about coils, and f104, and j127, j107 from other willaims wpc boards I forgot whats what...my bad.... but I figured if I had someone knowledgeable that could help diagnose this I would go step by step and hopefully figure out if there is a short in the wiring, coils, or backboard.

Do you have a manual? That is always important in tracing this stuff. I don't know your game but I bet the melted wire that you repaired was not the problem but a symptom. I imagine that you have a shorted coil and maybe associated transistor.

I recently had a mosfet short and fry a coil and smoke before the fuse blew. I knew which coil it was and went back to the board and tested the transistor comparing with the others and it was clearly bad. very easy fix when you know where to look.

A multi meter and a little guidance are helpful. PB WIKI and pinballrehab have good instruction

#6 6 days ago
Quoted from Johnnys:

When I plug in j107 and leave j127 off then only 9-16 do not work.
Im running out of fuses so I only tried powering on without j107/j127 hooked up and thats when I do not blow a fuse at F104 which is a 250v 3A SB fuse that pops during the first 5 or 6 seconds I'd say when the machine is going through its testing at start up while both j107 and j127 plugged in...

Try connecting J107 but leave J127 DISconnected. If the fuse still blows then you have a direct short somewhere in the VIO-ORG daisy chain of wires in the playfield. If it doesn't blow then you've got a short somewhere on the other side (J127). I don't think it's the second case because a solenoid would actually fire when you power on that would cause the fuse to blow. It's more likely you have a short in the VIO-ORG wires.

If that is the case then you'll need to trace the wire in the bundle of wires to see if there's any obvious place where the insulation is missing or there's an errant connection to ground. Another thing you can try is to lift the playfield up and power on. Sometimes a wire touches a part that is connected to the ground braid throughout the cabinet and that's your short. If it blows with the playfield down but NOT with the playfield up then it's positional depending on the playfield and that should help you locate the problem.

That's where I'd start.

Finally ... if you want to rule out your driver board you can swap the board from your Party Zone.

#7 6 days ago

Also, put your location in your profile. You'd be surprised at the generosity of pinheads that might be local to you and would be willing to help out. I've helped locals many times.

#8 6 days ago

Ok, thank you to both. Im on my lunch break and will try these things when home tonight. I do have a manual that I downloaded. Its about 200+pgs for bram stokers dracula and there are lots of pages that contain pics of the boards and components but I can not tell which transistor, diode, or whatever else is connected to the violet-orange line. I am totally new to electronics as well although I have been cramming as much as I can learn past couple of days...I like to think that I am a fast learner. I went out and bought a multi-meter digital (auto ranging) and a logic probe but still learning to use them...with a bit of help I am also a good listener! I am from RI east coast and will update my profile as well.

Thanks to you both. I look forward to any other help as we move through this procedure.

PS....as far as swapping out party zone board, is there anyway that a wiring/coil problem caused something to burn on my dracula. I would hate to swap boards and end up popping something on that as well!?!?!

ok, I'll check back around 7pm EST. Thanks again.

John-

#9 6 days ago

The inside cover of the manual shows the Solenoid/Flasher Table. That'll tell you everything you need to know about each solenoid. "Xister" means transistor.

#10 5 days ago

You have a multimeter, so that's good. Here's some things to check:

With power off, Pull J107 and J127. Put your meter on Ohms or Continuity (Diode beep). Put the black lead on the ground strap in the head. With your red lead and maybe a paper clip, depending on how sharp your leads are, put it on each pin of J107 the female connector (not the male pin on the board). You should high impedance (ohms) or OL (diode). If you read 0 or beep, then that violet wire is shorted to ground. Either you have a burnt/exposed wire that's touching something, or you have a shorted coil with a shorted ground. Start visually tracing the violet wire and look for anything suspect.

Report back if above fails and you don't find something obvious...but it may take de-soldering at the coils to further test, so do you have a solder iron?

If all the pins check out, with power off, reconnect J127. Then check J107 again on ohms. See if you read low impedence through a coil...6 ohms or less. If you do, you have a short on a transistor on your board that's locking on a coil at power up. You mentioned something about coils during the boot/testing. You should hear no coils firing during boot and going into attract mode. If you do, then you have an issue with the blanking circuit on your MPU, OR you have one or more coils with shorted transistors or logic ICs on the driver board.

If both of these tests pass, then reconnect J107 and J127. Take the glass off the PF. Power on machine and listen very closely if you hear any coil fire. If it does, immediately turn machine off, note which coil and report back.

#11 5 days ago

I have used this online coil resistance chart in the past.

https://www.flippers.com/coil-resistance.html

It is helpful in giving anticipated readings but you can also compare readings on similar coils.

#12 5 days ago

Im just taking a break from work but had to check these replies. Thanks- While testing ohms on j127 does it matter if the f104 fuse is blown or should I put a new one in to close that part of the circuit?

Also, I do have a soldering iron.

Last, even before machine broke, with or without j107 and j127 connected on power up the machine also fired a few coils from time to time to set up game play if needed. IE) the gates for mist ball would release ball and then ramp would lift up and new ball would be loaded, etc. before entering attract mode.

Now with j107 and J127 unconnected with no balls inside machine on power up the mist motor may turn on and return to right side of playfield, the mist gates open to release balls but none there, and then thats about it since no balls in machine and even if there was the through coil wouldn't fire to load balls to be launched under ramp etc.

*** Also, for testing ohms of each coil after I check j107 / J127 should fuse be good, should j107 and 127 be plugged back in? and since no diodes are on coils but somewhere??? on back board do I check across the lugs on coils or do I need to locate their matching diode?

Thanks All!

#13 5 days ago

You can leave fuse out for tests. We're just trying to find a playfield wiring short or possible shorted coil and/or transistor. Only when applying power and listening for coils do you need the fuse back in.

Yes on BSD loading of the mist magnet is normal, but should only involve the ramp solenoid. And this happens after the mpu boots. You want to be listening for coil activity as soon as you power up, before the mpu boots and the led on the mpu starts flashing.

#14 1 day ago

Sorry I have not had time to try the above advice. I really appreciate you reaching out to me. As soon as I have time this week I will take a better look at the machine. I ordered the schematics hoping that may help me a little even though I am very new to electronics figured it couldn't hurt having. I will post again once I proceed. Thank you everyone again and I hope you will continue helping once I reach out.

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