I've had a Firepower machine for about 4 months and the game seemed to be running fine. I got my hands on a CPR playfield so I decided to do a swap a few weeks ago. When it was done I fired it up it and it went into attract mode. Yay! I put it into diagnostic mode and found that none of the playfield solenoids were firing. The fuse was blown so I replaced it. I also noticed that the 6F3 4 amp logic fuse was blown so I decided to put in circuit breakers for both 6F2 and 6F3 to try and trouble shoot. I checked wiring and switches and everything seemed okay. So now, almost every time I power the game on, the 6F3 breaker pops but the game plays just fine. On some occasions, 6F3 pops followed by 6F2. I'm a bit confused by this as I figured something shouldn't be working if fuses are blowing.

The other challenge I have is with the sound board. I noticed that the F2 fuse was blown but I still had sound. When I replaced the blown fuse the other night, the F1 fuse also blew. The F1 fuse was only a 2.5 amp slow blow so I replaced it with a proper 4 amp slow blow. Now every time I turn the game on, I get a nice hum from the speaker for a few seconds and then the fuses blow. I put my 4 amp circuit breaker in F1 and left F2 empty as this was how I was getting sound before. No dice. Power up, hum, then circuit breaker pops.

So I've got a couple of problems to deal with that didn't seem to be there originally. Of course I learned the basic lesson that I should check all the fuses from day 1 and make sure they are correct. I'm no electrical whiz but I can probably do some basic troubleshooting with my DMM. I have a local tech that I can turn to if I have to but I thought I'd give this a try with forum help first.

I've attached some pictures of the power supply board on the advice of vid1900. Hoping someone can point me in the right direction.

Thanks,

Dino Z.

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Okay, I will replace the cap. Should I replace the other ones on the board while I'm at it? I've been shopping around. I'm going to put an order in to Digi-Key. Can you verify that this one will work for the 12,000uf cap:

http://www.digikey.ca/scripts/DkSearch/dksus.dll?Detail&itemSeq=176402883&uq=635731784556427923

I was also going to order the IRF9Z34N MOSFETs you mentioned to replace the TIP42 lamp matrix transistors. I believe these are the correct ones:

http://www.digikey.ca/scripts/DkSearch/dksus.dll?Detail&itemSeq=176405484&uq=635731784556427923

I'm also going to add the fuses to the bridge rectifiers as you suggested. Is there anything else that I should add to my list?

As far as testing the game with only the transformer attached, do I just need to pull 3J3, 3J4, 3J5 and 3J6 and start up the game?

Thanks,

DZ.

And they have everything kitted up. That helps. You are okay with 12000uF 25volt cap for C15? Your guide recommended a 15000uF 35volt cap.

Was I correct about testing with the transformer only? Just pull 3J3, 3J4, 3J5 and 3J6 and power on and see what happens?

Thanks,

DZ.

The parts have been ordered. In the meantime, I pulled 3J3, 3J4, 3J5 and 3J6 from the power board but the breaker is still popping. What should I try next?

The breaker I have attached to 6F3 pops every time I turn the power on. Every so often 6F2 pops as well but it's pretty rare.

Okay, so I checked those two diodes. D4 reads 0.001 both ways and D3 settles in around 0.5 one way and shows 1 on my DMM the other way. I will get a couple of new diodes as you recommended and replace them. My parts have shipped from Great Plains, just have to wait for delivery. I will report back once I get all the bits and pieces in place.

Thanks!

DZ.

Got the replacement diodes today. I had no issues getting the old ones off. However, I made a bit of a mess of the two top solder points on the back side. The solder seemed to flow wherever it wanted to and ended up bridging the two points and the fuse holder above them. I only have a soldering iron and an inexpensive solder sucker so I did the best that I could. I'm assuming that those two diodes lead to the F5 fuse so this shouldn't be an issue. I looked at the schematics, wiring diagram and circuit board and the traces don't lead anywhere else. The bottom solder points were neat and clean. I just want to confirm about the now conjoined top solder points before I plug this thing back in and power it up.

Got to get better at this soldering business or leave it to the pros...

Thanks,

DZ.

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Thanks guys. I have an inexpensive 25 watt iron. I think part of the problem is that it has a conical tip and it's worn down. I need to replace it and I'm sure I read somewhere that I would be better off with a chisel tip. So it's either time for a new tip, a new iron or both. When I first took off the old diodes the holes were fine. I should have just soldered in the new ones instead of screwing around.

So at this point, am I okay to plug the board back in and test it out? What do you think?

I will convert it to a chisel tip. Right now the 2 new diodes are soldered in. They aren't moving and seem pretty solid. It's just that the top two solder points are a bit messy. There's no way they are coming out unless I heat them back up. It's just that the two solder points for the diodes and the trace for the fuse are all connected.

Can I just plug in 3J1 and 3J2 to test with the transformer and see if it's still blowing fuses?

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Just an FYI. I ran a diode test on both diodes with my DMM but I measured from pin 10 and pin 11 on 3J1 to the far side of the F5 fuse. I got 0.423 and 0.444. I also tested for continuity from the top pin of the diodes to the far side of the F5 fuse and got no resistance.

I think I'm in good shape to power this board back up but I will wait to hear back from the experts before going ahead.

Thanks!

Well that was very reassuring!

Plugged the transformer in first and fired it up. The breakers did not pop. Cycled the power a few times to make sure. All was good so I put in a couple of fuses instead of the beakers. Again nothing blew. I plugged everything back in and started up the machine. I was able to play a few games without issue other than one ball lock switch not working. So it looks like the new diodes took care of the fuses blowing on the power board.

So now I have to deal with my sound board blowing fuses. New thread or just continue with this one? I plugged my breakers in instead of fuses. When I turn on the game I get a loud steady hum from the speaker until the breakers both pop.

Looking for direction on this. I will do some research on what to do with the ball lock switch that isn't working. Maybe time to learn about the switch matrix!

Thanks for the help so far!

Yes, both fuses blow on the soundboard. Can I test the bridge to see if there is an issue? Anything else I should test?

As far as the switch is concerned, in switch test mode, it does not register anything, whether I drop the ball in or lift the playfield and manually engage the switch. I know for a fact it was working before as I tested each switch individually in test mode.

Okay guys, after a few weeks of vacation time I'm trying to pick this up where I left off!

barakandl, you mentioned the bridge. Is that what I have circled in the image? I haven't pulled the sound board out of the game yet. I'm assuming that I will be able to test the individual diodes from the back side of the board or am I mistaken?

firepower_sound_board.jpg

With respect to the ball lock that wasn't working, after thinking I had some major issue (and I probably still might) a bit of wiggling of the 2J3 connector seemed to get all the switches working again. That probably means that I might have to do some work on the connector at some point, perhaps reflowing the solder joints. I did learn a bit about the switch matrix though.

For now, I'm okay, so the focus is back on getting the sound board working.

Any advice on this guys?

Thanks!

barakandl, I will pull the sound card out of the game. I can't see anywhere to test it from the front side so can I assume that I will see some solder points on the backside once I remove the board?

Andy_B, I'm going to keep an eye on the game for a while. I know at this age a lot of these connectors should be replaced. I want to tackle one job at a time if possible!

Thanks for the input gentlemen! I will report back with my findings and additional questions!

Okay, finally got around to pulling the sound board out of the game. I've run some tests on the bridge rectifier with my DMM based on instructions that I found online. I guess the fact that when I test the two AC pins (pins 2 and 3) with the meter and get a reading of some type, the rectifier is definitely bad. Does this make sense? I've run the tests with pins 1 and 2 and then 3 and 4 and then reversed the leads. On the 1-2 pins I'm getting what is expected but on the 3-4 pins I'm getting measurements when I shouldn't. Safe to assume it needs replacing?

barakandl, you mentioned this could be replaced with something beefier than the original 3N253. Do you have a part number I can use?

Thanks!

So I had a look at the datasheet and the pins are laid out as I expected. POS DC is pin 1 on the left, AC are pins 2 and 3 and NEG DC is pin 4 on the right.

I tested the following the other night with the DMM:

POS DC and AC pin 2 - result was .5 or close and then nothing when I swapped the meter leads

NEG DC and AC pin 3 - result was .003 or something similar regardless of how the leads were connected. Definitely not .5 or anywhere close.

I will test again when I get home today but I'm pretty sure the NEG DC side is bad. So if I'm replacing this part is there a better choice than the 3n253? Perhaps something more commonly available?

Thanks!

So basically, I can test all 4 diodes in the bridge by switching the leads to the proper pins based on the schematic? The combination of pins would be 1 and 2 (top left diode), 1 and 3 (bottom left diode), 2 and 4 (top right diode), 3 and 4 (bottom right diode).

Just trying to educate myself here to understand how the internals of the components actually work.

rectifier_3n253.jpg

So I tested everything again just to confirm. The 1-2 and 1-3 test resulted in .517 and .516 respectively, the 2-4 and 3-4 test resulted in .004 and .001 respectively. Good to know that the bridge is bad and needs to be replaced.

The best I can find locally as a replacement without spending $20 is a 3N256 which is 2A 400V instead of the original 3N253 which is 2A 50V. If I'm reading the datasheet correctly and have done proper internet research, 400V is the peak reverse breakdown voltage. I interpret this as higher is better. Will this component be a safe replacement or should I be looking at other specs?

Sorry for asking what might be obvious questions for some of you. I'm a software developer at heart not an electrical technician but I'm trying to learn!

Thanks as always for the help!

Well that did the trick! Got the old one off the board, got the new one on, hooked everything back up, flipped on the power and got the old familiar hum. Started a game and all is good! Fuses are no longer blowing and the game seems to be running well for now. Still got some work to do but I'm pretty happy at this point!

For those of you that have good soldering skills I'm envious but hopefully I'm learning. Thanks to everyone who provided me with advice and guidance on how to solve these issues!

Dino Z.