Hello All - working on a Firepower II that I picked up recently. When I got it, the first thing I found was that it would start a game, but no ball would kick out. I checked and found the Solenoid Fuse (2.5A, slow blow) was blown. I replaced it, and the game started playing just fine. Played numerous games, everything seemed to be working aside from the lower right pop bumper. I checked the contacts, cleaned everything, and tried again - still dead.

I probably tested/played about a dozen games, and turned the game on and off a couple of times between them. Everything seemed fine. Then I powered on the game (it had been off for a couple of hours) and pressed start. Same original issue, ball didn't kick out. Checked the Solenoid Fuse, blown again.

I'm not really hearing anything locked on, but I'm wondering... is it the "dead" pop bumper perhaps? I know this can be caused by a lot of things, so I figured I'd solicit some advice on the forums before tearing anything apart hunting. I figure I should check the resistance on that coil, and probably track down and check the bridge rectifier. Any other suggestions?

Thanks

Thank you for the reply frunch. I'm completely new to System 7 (so far I'm familiar with MPU-200, System 3, System 80b and EMs), so this is good info. I did notice after starting the game, maybe 10 or so seconds after powering on, I would hear a very faint "click" or "pop" like it was doing something after the initial boot up finished. Wondering if that was some final step in the boot up that is doing what you said.

Looking over the power board, I see some suspicious looking caps and such too. I'll get some pics of everything and post as needed. The "AA" battery pack is still in there, and I see a bit of corrosion, so I need to get all of that out and cleaned up ASAP as well. I'll test that pop coil and perhaps just detach it for now as you said, just in case.

Oh nice, I never noticed that before, and I've bought some stuff from him before (NVRAM for some games). Sweet, thanks, I'll check that out.

Some pics as promised. The fuse in question was removed when I took some of these. New caps needed I would think, and that blue axial one on the right looks a little puffy to me for sure. On the MPU you can see the evil battery pack with a bit of corrosion, as well as a tiny bit down below on the other board (no real damage, but clean-up needed). Definitely some work to do here.

FP_MPU_1 (resized).jpg

FP_PSU_cap (resized).jpg

FP_PSU_1 (resized).jpg

PF_Battery_corrosion (resized).jpg

I'm going to try disconnecting the pop today to see if that's the problem. I was going to wait and order that fuse board first, but I've got a small pile of fuses so it's worth at least trying it with the pop disconnected as a test. I'll report back as soon as I try it!

Working on mine now... will report back later as to what I find and what happens

Okay, I tested all the solenoids. At first I got weird readings (slings showed 2.6, pops 3.8, etc) even though they're all the same coil SG1-23-850DC. Reset my meter, then I re-tested and everything showed the same: 5.2ohms. Coil chart says that's about right, so I should be okay there.

Checked the ground wires that are wingnut screwed to the base of the head, I see two there, a wire and a ground strap. Seem on there tight and test okay. It's just two connections there right?

I replaced the solenoid 2.5A sb fuse and fired up the game. I hit start immediately and a game began. Ball kicked out, flippers worked. Started to play, left two pop bumpers worked, right two didn't. Then the fuse blew again and that was it. Ball drained, but can't kick out, so I was stuck.

Checked the fuse holder, nice and tight and tests good.

Okay thanks mof, I'll get the saver board. I think some NVRAM makes sense I'm that order too. Beat place to get that 2A breaker?

You guys mean replace the 40-pin section with a kit like THIS one?

Fuse saver and nvram boards on the way. I'll start there and work my way through things.
I thought the RAM was hard-soldered onto the board for this game, but looking at mine it appears to be socketed, which should make that swap easier. If I pull the original, put in the NVRAM, then I can just remove the batteries completely right? I did this with my 80b games and it worked out great.

Finally back for an update. Due to a combination of things (weather, time, etc.) it's taken me a while to get the Firepower 2 into my game room so I could work on it regularly. I had it at a nearby friend's place for a bit. I need to reattach all the connectors and such, since I had to remove the head for transport. (Question below on that)

Okay, so I have the "fuse saver" board in hand, and plan on trying that out today hopefully. I plan on ordering some of the other items mentioned above, but figured I would try the fuse board first.

Quick Ground Question for those that know: How many grounds are connected to the wing nut in the head of the game? When I bought the game, the head was already removed so I couldn't take connection pics. The label (see pic) seems to make it sound like 3 things should be connected here. I found a ground strap one and (1) White-Red off-shoot from a large black connector wire bundle (Playfield I assume). I haven't found a second White-Red wire as the label implies. Pics attached if it helps.

Ground_1 (resized).jpg
Ground_Label (resized).jpg

I hooked everything back up, installed the "fuse saver" board, fired it up and it all seems to be working aside from the lower right pop bumper. Tested the coil resistance, seems okay. Switch seems fine. Guessing I need to dig deeper.

I played about 15 games, no fuse blow so far, but I recall when I first got it I had similar success for a while before it started popping. I'll keep doing some testing, etc. I'll need to take things apart, clean the mild corrosion off a small spot on the board, get rid of the battery pack or remote it... lots to do.

Good side news though - I was able to locate a much nicer used playfield through a friend, so eventually I can do a full playfield swap and have a pretty nice FP2 in the end.

Thoughts on the dead pop and ground wire question?

So I checked the schematics and the dead pop bumper goes through Q12. Want to take a guess as to where the only spot of battery corrosion is? Yep... right on the area where Q12 is. See pic for reference (Q12 is on the right). I've neutralized and such, but I'll need to do some clean-up, testing, and likely replacing. Guessing this is why the pop is dead, since I doubt it's a coincidence.

FP2_Q10-Q12 (resized).jpg

Could you clarify what you mean a bit? I just don't want to do the wrong thing. I assume you're referring to the large transistor in the pic (Q12). When you say ground the metal tab, do you mean connect ground to that blackened looking portion with the hole in it?

I'll try that and report back, thanks for clarifying!

I actually neutralized the corrosion per instructions I found on Pinside, so it shouldn't get worse (hopefully), but to be sure I'll be pulling everything out, cleaning, etc.

Back in a bit after I do the testing

I performed the grounding you mentioned, and the coil fired perfectly fine (scored the points and such too). So per your post, the coil is good and the wiring from the driver board is good. Transistor ordering/replacing time it appears. Thanks!

I just finished cutting off the battery pack and replacing the 5101 with a NVRAM 5101 I had already ordered, so at least that's done. There's some corrosion under the battery pack area, but doesn't look horrible. More clean-up time.

Got the transistor and 2N4401 in the mail, so I'm ready to try swapping those out. I had already ordered the TIP122 before your post about the TIP102 alternative, but we'll see how this goes.

Unfortunately, I turned the game on this morning (been playing it a bunch even with the one dead pop) and the displays were out. I've had no problem with anything aside from the single pop for weeks, so this surprised me. I checked and the 1/4A fuse was blown (labeled high voltage on the chart). I pulled the fuse and saw it was a 1/2A instead of 1/4A like the label says should be there. I don't have any replacements for that size at the moment, so I'll have to order.

I'm concerned what caused it to blow... it's been great for a while. Starting to wonder if I should be doing some power supply fixing/replacing to ensure everything is as it should be there. Everything in this game seems original.

Not that I noticed, no. I think maybe the credit display might have had a very slight flicker on one segment? Honestly, they all looked really nice. Once I get replacement fuses I'll see what happens. If it blows again, I guess I'll have more to track down. In general, I'll probably need to just attack rebuilding/replacing a lot of old stuff. Definitely had fun playing it so far though, which is nice.

Yea, I'm pretty sure everything is original on this machine. Caps look a little iffy to me. Check out the pics in post #7 above and you can see what I mean. I found some fuses, ordering them now.

Quick question: in the manual it shows F4 as "Not Used", but my game has a fuse in there. Should I remove that?

Kind of weird someone has a fuse in there haha. There's an original chart right in the head near the board that says not used too, and yet someone stuck one there.

New fuses should arrive soon, caps too. Also picked up new inter connect headers and such, might as well pull everything and do some work.

I should probably go back and read all the guides, order some more stuff, and really go to town on these boards. Always tempting to piecemeal the effort, but it wastes time going back 5 times.

Hopefully next week when stuff gets here I can get some of this done and see where I'm at. First thing I'll do is pop that fuse in and make sure the displays come back up. If not, I'll report back and we'll see if we can figure out what's up.

Well, replacing the fuse didn't bring the displays back right away, and interestingly the part of the fuse that blows started to glow red, so not a good sign there. Time to do some work it seems.

Update: Power supply caps replaced, connectors redone and headers reflowed. Sadly, same issue. Displays dead, 1/4A fuse still glows red-hot after a couple of seconds with the game on. Dang it.

I'm assuming they're saying unplug the power coming into the master display board that's on the back of the swing-out front panel. I took that connector off, and still the same glowing fuse issue. I left it on for about 15 seconds and started a game. Fuse didn't blow, but stayed glowing. See attached pic. Note: I think this is supposed to be a 32mm slow blo fuse... I think I was sent 30mm fast ><

Fuse_glow (resized).jpg

I didn't like that the markings on these were scarce. It's got "T250mA" and "250V" which I expected, but the only other clear markings on the fuses are the UL approved stamp and what might be "sb" in a circle, but it's really hard to tell. Just in case, I just ordered some name branded Littelfuse 3AG 1/4A slow blows in an actual package instead of loose, random ones from eBay like this first batch.

Regarding the HV section, I think someone may have rebuild it before, or at least some of it. The transistors and several resistors look to be soldered by someone after the original manufacture, so I would guess it's been done.

Should I head over to the Test Points on the MPU and take some readings there?

Looks like the GPE kit shows out of stock, so I'll have to piece-part it together using a list. Unless there's another known good place to snag the kit w/o the caps (since I did those already)? Been googling around. Suggestions welcome!

I did some quick testing, and aside from the known dead pop, everything else in the game continues to work great. So if I can get this new display dead thing figured out, and that pop going, I think I'll be okay. Is there any chance the interconnect between the main boards could be part of this display issue? I haven't replaced that yet, just got the stuff the other day.

I think I've cobbled together all the pieces I need based on the HV parts list on GPE's site. Thankfully, even though they don't have that kit 'in stock' they still list everything in it, so I can source it elsewhere. I found most of it at Mouser, aside from I think one transistor they're out of stock on right now. Have to snag that from eBay and wait a little longer for it to arrive it seems.

My plan is rebuild the rest of the HV board, replace the interconnect stuff between the other two boards, and read up on anything else I should do.

Regarding that non-working pop ... a while back you had me ground it at the transistor to see if it fired (and it did). The other day I did an in-circuit test of the transistor and the numbers matched what is expected from a good transistor. I thought that was odd, but since it's on the board who knows. I have the replacements, so I'll still do that when I do everything else. But part of me wonders if there's something else along the way wiring or trace-wise that's not connected. Another strange thing I noticed: the schematics don't quite match the wiring/board. It all looks to be original and not tampered with, but the diagram doesn't match reality. I'd have to look again, but it was something like the top left bumper seems to go to the transistor marked for the bottom right, and vice versa. I will look again, but it seems like they're mixed up. It doesn't really matter from what I can tell, but it was interesting. I'll double check that and report back on it eventually. Need to get the above stuff done first though!

Will do on the pop, thanks.

Update: So I received the new fuses. Definitely the correct size, rating, etc. this time. Hurray. That's the good news. Bad New: Blew immediately when the game was turned on.

Ordered all the parts to rebuild the HV section. One transistor might take a while, the rest should be here in less than a week. Once everything arrives, I get that stuff installed and go from there. While I wait, question: If I rebuild the rest of the HV stuff, and the fuse still blows, what next?

MJE15031 - Mouser had all the rest, but that was backordered it seems.

Okay, makes sense. I've got 4 more fuses (and can get more). For now, I'll wait until I rebuild that HV section before bothering to try another. Would it be worth disconnecting everything aside from incoming power to the HV section and trying a fuse in there to see if it blows? Based on what you're saying, there's no sense in that, so I think I just hold off.

Going back to my original Solenoid fuse issue, I find it interesting that it stopped blowing after I installed the "fuse saver" board. Then again, I did improve the ground connection area in the backbox (wasn't making great contact) as well, and did a little clean-up on some other stuff. I guess any number of the little things I did may have fixed whatever was blowing that original Solenoid fuse. Don't look a gift horse in the mouth I guess.

I'm basically in a holding pattern for the moment - I hate waiting, but hey, I can do some cosmetic work in the mean time. I also have a guy here in town that wants me to go look at his Stellar Wars, and since it's similar to Firepower II in some ways, maybe I can use some of what you guys have shown me to figure out his issue.

Update Time - So I pulled the MPU and Driver board. Found some corrosion "dripped" down the back of the driver board, but nothing too serious. I was able to clean it up using suggested methods, and tested out traces, no issues that I could find. I took the time to replace the 40-pin connector/headers, so that's all done. It was much easier than I thought it would be, so that wasn't so bad. I also replaced 4 transistors on the driver board that were looking iffy as mentioned above, one of which was directly related to my dead pop bumper. Sure enough, after pulling the transistor and testing it, it was no good, so the new one will hopefully fix that issue.

The parts for finishing the HV rebuild should be here in the next few days, so I'll pull that and get those installed next. With the transistors, looks like some white thermal compound is on there. Should I clean, remove, and replace that? I have plenty of CPU heatsink compounds lying around, would that work?

I had read about that, but that picture in the link is useful, thanks! Waiting for the last few parts to roll in and I'll get cracking on the HV rebuild. Once that's done, I'll reassemble everything, cross my fingers, and fire it up again.

So when I pulled the power supply board again to begin the rest of the HV rebuild, I looked closer at the transistors already on it. They're already the 'newer' transistors (E15030, E15031). But as you can see in this pic, the legs are NOT installed differently, as cited in the document you linked. I'm guessing there's a good chance this might be causing some issues? With both wrong like this, I'm curious why not more stuff was messed up. Thoughts?

FP2_PS_Trans (resized).jpg

Maybe Mof can drop back in and offer an opinion. Very weird. I'll double check the back side of the board again, but I didn't see any jumpering or re-wiring ideas that would allow them to get away with installing it as shown.

I am a little worried though... should I still do the cross-leg thing? What if somehow they worked around it and I can't tell, and then I cross legs on the new ones, and then something goes kablooey? Should I just go for it as GPE says, and say screw it?

HA! I just came back to post about the System 11 board possibility. Here's the part number on the board: 5765-09466-01 . Googling that I come up with results all saying System 11 (but not if it's late series or not). Think it's safe to assume it is and go with the normal non-crossed legs? For now I'll replace everything else until I get an official verdict. Last thing I want to do is kill this board haha.

Think it's worth changing everything else, leaving the transistors as they are, and then trying the board? Or just wait?
It's weird that the game was 99% working as is (just one dead pop bumper) before the recent displays going out thing. Hard for me to believe the transistors could be completely done wrong and the game would still work like that haha.

Well, when I first got the game, it was powering on, but blowing the solenoid fuse immediately whenever a game was started. The batteries were dead too. I reseated all the connectors after moving it into my place, and tried it again with a new fuse. The game played a bunch of games, then blew the fuse again. I installed a NVRAM and Fuse Saver board next. After that, the solenoid fuse never blew again. I probably played about 40-50 games with no issues aside from one dead pop bumper. Displays, everything, all worked great.

Then one day the displays were simply not on, and when I checked the high V fuse it was blown. Replacing it just blew it again. That's basically where I was at when I started the HV section work (capacitors), and you know the story since.

Yea, I probably should try another thread, since people might be skipping by this, and the title is about fuses and not the transistors. I'll give this a little longer to see if anyone else chimes in first.

Just reporting back that Firepower II is back in action! Marking the thread as problem solved. For those keeping score:

- Rebuilt the HV section (caps too), found incorrectly installed Q1 and Q3 transistors, replaced and properly installed with suggested cross-leg method
- Replaced/repinned several connectors, especially the 40-pin inter-connect
- Replaced several bad transistors on the driver board
- Removed battery, cleaned up minor corrosion, installed NVRAM
- Installed Fuse Saver board

End result, no more fuses blowing, pop bumper that was dead is working, Displays back on and working great. Looks like it's time to move onto the cosmetic side of the project for now. Lots to do, but hopefully good on tech for a while.

HUGE Thank you to all those that offered advice in my threads and via PM. Couldn't have done it without all of you. Thanks!