(Topic ID: 240135)

Hollywood Heat Drop Target Coil Blowing Fuse (Always energized)


By atrainn

75 days ago



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  • 18 posts
  • 5 Pinsiders participating
  • Latest reply 68 days ago by atrainn
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#1 75 days ago

Hey guys,

I've been troubleshooting this for about a week now and just cannot figure out what the problem is... My Hollywood Heat pin keeps blowing F11 (1a slow blow). I've narrowed it down to the left drop target bank as being the issue. I've noticed that the coil for resetting this bank constantly stays energized until the fuse blows.

So far I've:

1. Replaced the driver board with a NiWumpf board (the original board had some hackey repairs)
2. Replaced all the diodes for the relays and the coil diode
3. Replaced all three transistors 2n879. Replaced them with 2N5884.

This hasn't resolved anything. I can't find any shorts in the matrix anywhere...so I'm not sure what the issue is. I'm debating on just replacing every part in the drop target bank and hope that resolves it. The manual isn't amazing in it's documentation of the bottom of the PF, so maybe I'm just going down the wrong path entirely.

I've already wasted around a dozen fuses in my testing...so I'm kind of out of ideas. Any help is greatly appreciated.

#2 75 days ago

Well I've tried a bit more troubleshooting and I think it might be an issue somewhere in the switch matrix or some issue with the game detecting that the targets have been reset? All transistors have been replaced, and ultimately the board was replaced...

I tested the left bank on the right bank connector, and that worked just fine, so the mech is certainly not having issues. I've replaced all of the diodes in the matrix as well...but to no avail. I'm totally out of ideas at this point.

#3 74 days ago

Did the game only begin doing this recently, or is this something you've been dealing with for as long as you've had it?

I can't access schematics, since they're not available on ipdb.org. Any chance you could post the relevant part of the schematic for the coil you're having trouble with? Have you identified exactly which transistor drives that coil?

#4 74 days ago

it's q61 q62 on the driver board. there are under playfield transistors for the tiny coils that drop the individual targets. what does switch test say?

leftbank (resized).jpgleftbank2 (resized).jpg
#5 74 days ago

sorry i cant read, you said you replaced everything, could it be the cpu?

#6 74 days ago

I was starting to lean towards CPU, but at this point I think there must be a short somewhere in the harness that I haven't found yet. The fuse started blowing instantly today, before that coil even fires when I turn the game on. I've looked at every inch of the harness and don't see the short though.

Switch test seems to be reporting ok, though I'll need to sort out the fuse thing and see if this is still a problem once thats resolved.

#7 74 days ago

Check the 4.7K resistors on the base of the final drive transistors. These resistors are required to turn 'off' the transistors when they are no longer being driven by the driver board.
See illustration by supermoot for the pullup resistors on Q6, 7 & 8.

#8 74 days ago
Quoted from G-P-E:

Check the 4.7K resistors on the base of the final drive transistors. These resistors are required to turn 'off' the transistors when they are no longer being driven by the driver board.
See illustration by supermoot for the pullup resistors on Q6, 7 & 8.

I'll just replace all of those resistors today and report back. I pulled them and they all tested ~4.7k

#9 74 days ago

Sigh...no dice. I replaced all the resistors in that bank and it's still doing the same stuff. The fuse won't blow if the left bank is unplugged...so there has to be a short somewhere but I'm sure as hell not seeing it.

#10 73 days ago

I have a feeling it's related to one of the switches rather than the coil. I unhooked the coil entirely and it still blew the fuse now, I've already replaced all of those diodes, but I'll keep looking into it. I give up for today though.

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#11 73 days ago

there are four coils on that harness! perhaps one of the other tiny ones. the ones for knocking down targets during multiball "in sync"

#12 73 days ago
Quoted from supermoot:

there are four coils on that harness! perhaps one of the other tiny ones. the ones for knocking down targets during multiball "in sync"

I did replace the diodes on those and tested them as well. I'm still skeptical of it being an issue with the target bank since plugging the right bank into the left exhibits the same symptoms. I'll get back to it tomorrow and see what I can sort out.

#13 72 days ago

I pulled all three relay coils out and tested them. The connectors on a few are pretty damn dirty, but they all test at 34 ohms, which is correct for these coils. One of them was giving me trouble in getting a reading at first, so I cleaned off all the old solder, sanded down the connectors a bit, and rebuilt them all. The one that was giving me trouble is testing more accurately now. I'll rebuild the wiring on this with new wires and diodes (again), then put it back in tonight or tomorrow. Hopefully one of these was the culprit for the fuse blowing.

#14 72 days ago

Hollywood heats drop targets are computer controlled. As they sync drop with the other drop target bank when hit.

I would check both banks. If that fails, if you have not done the ground mod. I would do that first. To eliminate the known grounding issues with 80b games.

#15 72 days ago
Quoted from erak:

Hollywood heats drop targets are computer controlled. As they sync drop with the other drop target bank when hit.
I would check both banks. If that fails, if you have not done the ground mod. I would do that first. To eliminate the known grounding issues with 80b games.

Thanks for the suggestion. I looked into it and this doesn't have the ground mod. I'll take care of it this weekend.

#16 71 days ago

Just a minor update. I finished rebuilding the bank. All the coils test at the proper resistance, and all switches are working. I rewired it all up, with no change. The left bank still blows the fuse, the right bank still works fine with either mech setup. Oddly now I'm noticing the right bank center target is no longer standing up with either mech plugged in. Since those relays seem to all be on the same circuit that could be a hint on what to look into.

#17 68 days ago

I did find the wiring for the center relay on the left side was actually wrong, so that fixed that. I pulled the driver board out and tested the transistor that drives solenoid 5, it seems fine, same with the transistor on the old board. I tested all of the diodes for the switches, and they all test properly and the switches seem to register, inspected every mm of the harness, found no shorts, quadruple checked all of the wiring to make sure it is all correct, and finally I added grounds to all the boards. After all of this it is still doing the same crap. So I am totally out of ideas. I might just see if someone in the area wants to come take a look.

#18 68 days ago

Well you're not going to believe this, I swapped in the old driver board just for the hell of it and the game works perfectly now. Maybe I coincidentally received a faulty driver board? It seems like the issue might have just been the relay being wired wrong from the start.

A new issue popped up of course lol, every time I hit the right flipper the game will play the coinup sound and award some points. So it's definitely tripping a target somewhere. Now to track that down...

edit: the vibration was activating a switch

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