Just got a broken Firepower last week. When I got it all that it did was light up the GI.
In the last few days I have replace both male and female interconnects.
Replaced all caps on power board,.
Replaced lamp resistors.
Replaced most of the Scanbe sockets. Still have 4 left to go but none in stock locally at the moment.
Took the battery holder off the board.

After doing all that I put all the boards back in and powered it up.
Opened the coin door and turned the machine off and on quickly and the game boots into attract mode.
Used the coin switch to put credits on the game.
Pressed the Start button and got a ball served up and the game played great. Or so I thought. lol
After flipping the ball around a bit and everything working great the ball went into the kickback. The coil locked on and blew the solenoid fuse.
Replaced the fuse and started booted the game back into attract mode and now after taking credits the start button refuses to do anything. Just dead. Cleaned the contacts and still will not start the game anymore.
Any ideas are much appreciated.

Awesome info.
This is why I love this forum.
Thanks Levi.

It was a switch.
The game is working almost perfect now.
The top right pop bumper is sticking on and the coil is heating up. Did not have time to check if it is a stuck transistor or a bad release switch under the playfield.
If it turns out to be a transistor, does anyone with a manual know which one controls the top right bumper?

Here is a photo of my switch problem. A wire had somehow come completely off. Got it soldered back in place now.
Very strange that it even started the first time.

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Thanks. I briefly looked at that site but for some reason it is so small on my screen I can hardly read stuff

Went ahead and removed the driver board and took it over to my work area.
Both the Q6 driver and Q5 predriver test good. No dead shorts and they both give me the exact same values as the ones around them.
I went ahead and changed them out anyway but no dice, the coil still locks on when a game is started.
I replaced the coil as well and that still did not work.
I replaced the diode on the switch as it looked a little corroded and still the coil locks on when I start a game.

(Most of the time anyway). Sometimes it will let me play an entire game where the pop bumper works just fine and then the next game it will lock on.
I still have a few Scanbe sockets to replace, but I'm not sure if they would be causing this one coil to have this crazy problem.
Any ideas much appreciated.

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Just a bump as I edited two posts above as to what is going on with my stupid pop bumper coil.
I am starting to grasp at straws on this particular problem.
Once it is solved all I will have left is the player 1 and 2 displays do not have all the segments working.

Thanks Schwaggs.
I had read about cutting the cap off and it would still work, just not as powerful.
And since that is the only part (other then the IC chips) that I have not changed, I feel pretty confident that it may be the problem.
Maybe that would explain why sometimes the coil locks in immediately and sometimes it lets me play for awhile before deciding to lock on.

Well after cutting one leg off the cap, the pop bumper still locks on when I start a game.
So here is everything that is not causing it to lock on.
1. Not the switch being stuck on. And no solder has dripped and no tabs are shorted on the switch.
2. Not the Driver or predriver at Q5 and Q6 (replaced them both)
3. Not the coil or the diode on the coil (replaced them both)
4. Not the diode on the switch. (replaced)
5. Not the cap on the switch. (took it off)

The only part of the switch that I have not messed with is the tan colored diode or resistor. (Not sure which it is).
Not sure how to check and see it it is good or if it would even cause this problem.

What else could possibly be causing this to happen? It is the last fix before we can actually play a game and it is driving us nuts.

I found a thread on here where I guy had the same thing happening.
Unfortunately it never got resolved in the thread.
But someone did think it may be a bad IC chip.

Here is the response below that I guess I will need to check on.

"Next test the associated 7402 and 7408 TTL ics. Power off. DMM set to diode test. Red lead on ground. Black lead touch the associated pins on the 7402 and 7408 ICs. Again you should see .4v to .6v. A lower or short is indication of bad TTL chip. Use the schematic on IPDB to find the associated 7402/7408 pins".

Sorry for talking to myself, but this helps me. lol.
If I am reading the driver board schematics correct on firepowerpinball.com the two 7408 chips I need to look at are IC 6 and 7.
And the two 7402 chips I need to look at are IC 8 and 9.
Can someone with more knowledge then me confirm this would be the IC's that would short and drive this pop bumper coil?

Keep reading, because one way or another I will get this damn thing fixed.

Just checked all 4 of those IC chips. They all 4 test the exact same. Just the two ground pins on the ends beep.
Still ready for any more ideas on this. Pulling hair out now.

Thanks a million. I will get right on that

Ok. The coil energizes with the top left plug pulled out. So we have a chip problem.
I have replaced four of the seven 24 pin scanbe sockets. I still have 3 to go but my shop is out of stock.
I also still have to replace the 40 pin one as well which I can do on Monday.
However I do not own a logic probe and need to find out exactly which 7402 and 7408 chips to check.
Any way to do it with a multimeter? If not I would just have to replace the ones that control the top right pop. (I dont get any dead shorts or strange readings by putting meter on diode mode and touching red to ground strap and black to the non ground pins of the chips).
I really appreciate the help. You confirmed that I was on the right track with the IC chips

OK. Here is where I stand so far with the top Right pop energizing at game start up.
I have replaced the 40 pin PIA chip and chip socket and no help there.
I also replaced IC 8 on the driver board with a new 7402 IC. I did this because after tracing the traces on the board from Q5 and Q6 this is the first chip they go to. But putting a new chip here did not help either.

I do have a brand new PROM board coming from Hans with the latest software and I will also be able to remove the 6 IC chips on the bottom of the CPU board as well. No idea if this will help with my problem or not.

If anyone has any ideas on which IC chip is causing my top right pop to energize, I am all ears. I am fast running out of things to replace so something has to work eventually.

Thanks for posting the entire path. That will help a lot.
And yes to the question of am I sure it is an IC chip.
The pinball Ninja himself helped me narrow it down pretty quickly.

I will try IC 6 tomorrow.
I have not touched any 40 pin PIA's on the driver board.
The 40 pin I replaced was IC 1 on the CPU.
I had no idea IC 11 on the driver board had anything to do with special solenoids.
Oh well, live and learn

Wow. After taking a look at IC 11, it may well be the problem.
Do IC chips leak?
What would this crap on mine be?
I was able to wipe it off with a paper towel but have no idea what it could be.
IC 6 of course looks great.

IMG_1450.JPG

Same chip after a light cleaning,
But the first three pads look dull and maybe even a cold joint on the first one.
I do not have a spare 6820 chip laying around so I will need to order if this is indeed the problem.

IMG_1451.JPG

Thanks guys. I will go ahead and replace IC 6 today and put a socket on IC 11.
I have a new 40 pin chip in my cart in case this one is bad.
I did not spill anything, that is the way it came to me.

And I do not have a probe. Just DMM.

I have to go shopping with my wife, but when I get back i can try the new IC 6 chip out.
I also removed IC 11, added a socket, cleaned the traces, and lightly sanded it's pins. (May still need a new chip).
Not sure why pin 1 on IC 11 has that empty trace running up to it that nothing goes in.

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Success!!!
Now I just. See to get the top segments on players 1 and 2 working.
I have tried swaping out displays but players 1 and 2 are both missing the top line.
Any idea what part might be causing this?

Awesome. I have the resistors from the last repairs on my Williams Hot Tip.
I remember now that the UDN7180 are hard to find. Last time it came down to taking a chance on a china knockoff, which I hear are sometimes not even the correct chip, or getting a new X-Pin LED board set. (I went with the X-Pin LED board set on that one.)

OK.
I changed out the resistor and no help with the top line of the displays.
Not sure if it matters but the top lines on the master display are out as well.
Only players 3 and 4 work perfectly.

Now on to the fun part.
I still have my old board from my Williams system 3 game.
However it has white UDN7180H chips in it.
My Firepower board has black UDN7180A.
Are these even interchangeable?
I was thinking maybe I could pull one off the system 3 board and try it on the System 6.
But I have never tried to de-solder one of these white IC chips before.

Here are photos of both boards. (Top photo is Firepower and bottom is from a Hot Tip)
Hate to have to buy another LED board set if I don't have to.

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I thought you might notice those. My brother and I kind of burnt those by accident.
We decided to just move the cables from one player to another to see if the problem followed the cables.
Well, we moved player 4 up to player 2 and let player 2 wire just hang there.
Big mistake as smoke quickly emitted from those two resistors.
However I guess we cought it in time as player 3 and 4 still work great.