Original Ms. PacMan cockatil fried (montor?)- help to fix/upgrade(?)..

cruiserandmax

Member

Donor 2017
Joined
Jan 2, 2017
Messages
73
Reaction score
1
Location
California
Original Ms. PacMan cockatil fried (montor?)- help to fix/upgrade(?)..

I have an original Ms. PacMan Bally/MIDWAY cocktail machine that I have been enjoying for many years (it is 100% original except I replaced the ROMs with the sped-up game version). Recently when I powered on the cabinet there was a loud "POP"/"CRACK" noise followed by a faint electrical/sizzling hum noise and a small amount of smoke coming from the cabinet. Needless to say I immediately pulled the plug. I opened the cabinet and could see that a thick upside down 'U' shaped piece of metal on the pcb associated with the CRT had exploded/cracked apart (see attached picture). At this point I unplugged the power connector going to the CRT and plugged the cabinet back in again- all of the cabinet lights came on as well as the cabinet fan. Unfortunately there is now no audio when I drop coins in and press start buttons- so I do not know if the main game board is broken, or if it is just a speaker problem (since the monitor is unplugged and I can't see anything). I can plug the monitor power connector back in- and there is still no change (monitor is now dead- and there is no audio response to dropping coins/pressing start buttons- volume adjuster on PCB is up).

At this point I'm not sure what to do- I think the built-in power supply is ok, but I suspect the monitor and (maybe?) the main game motherboard is dead..

Aside from this the overall condition of the cabinet and internal electronics/wiring appears to be in superb condition..

Is this cabinet a good contender to switch to an LCD screen, and replace the guts of the original motherboard to some kind of multi-cade/MAME/lots-o-games type situation?

Thanks for any advice/tips/pointers..
 

Attachments

  • broken_part.jpg
    broken_part.jpg
    199.7 KB · Views: 120
  • machine_lights.jpg
    machine_lights.jpg
    194.3 KB · Views: 66
Last edited:
That's an Electrohome G07 monitor... their flybacks frequently blow up like that. Not sure how you are with a soldering iron, but it's a fairly easy process to get it back up and running.

You'll need a replacement flyback, and likely the small fuse. While you have the chassis out, I'd also recommend doing a cap kit (replacing the capacitors). There is high voltage present, so you need to be careful.

If that's beyond your skills, there are also people that will do mail-in service... just pull the board and mail it to them.

DogP
 
if you want to tackle this repair yourself i have ALL the parts in stock on my site. let me know if you need any help with the parts. if you want to send it out and have someone repair it there are people on klov like Paul400, ecwestjr, buffett.
 
Thanks, DogP- I think I'm ok with soldering in new capacitors and replacing the flyback (now I know what it's called!)- is the small fuse you mention one of the array on the floor of the cabinet? Those are all still in good shape in this case (pic). If that's all it takes to get the monitor back up and running I'm up for it..

Do you happen to know if there is something about the design of this machine that would prevent the rest from working if the monitor were dead like this (ie- no sound coming from coin drops/game starts anymore?).
 
if you want to tackle this repair yourself i have ALL the parts in stock on my site. let me know if you need any help with the parts. if you want to send it out and have someone repair it there are people on klov like Paul400, ecwestjr, buffett.

Thanks- I ordered the flyback and monitor cap kit from your site- hopefully that is all I need. Though I suspect mainboard issues once I get the monitor back up and running. Fingers crossed...

Thanks again!!
 
is the small fuse you mention one of the array on the floor of the cabinet?
No... it's a fuse on the G07 monitor chassis. There are two of them... a larger one (F902: main monitor fuse), and a smaller one (F901: flyback fuse). They're both soldered to the board, and when the flyback blows, it generally takes out F901. You need to be careful though... when that blows, it leaves high voltage on the large gray capacitor, which really hurts if you touch it. Be sure to discharge it first (put a screwdriver across its terminals... will probably make a loud pop).

Also, because of the voltage on the capacitor, if you try to test the fuse with a multimeter, a lot of times the fuse will read fine, even though it's actually blown.

To take the chassis out, you'll also need to discharge the CRT tube.

There's a lot of good info here: http://www.pinrepair.com/g07/ and http://www.therealbobroberts.net/g07repair.html .

Bob Roberts is closed at the moment, but he used to sell a repair kit with a flyback, cap kit, HOT (horizontal output transistor), and fuses ( http://www.therealbobroberts.net/g07repair.jpg ). I'd recommend picking all of those up if you can find a seller that has all those parts... your larger fuse is probably fine, and the HOT doesn't always blow, but they should be cheaper than having to ship it later when you realize you need it. ;)

Do you happen to know if there is something about the design of this machine that would prevent the rest from working if the monitor were dead like this (ie- no sound coming from coin drops/game starts anymore?).
You should still hear the game coin up, run, etc... even if the monitor is dead. If it doesn't, I'd double-check your cabinet fuses.

DogP
 
No... it's a fuse on the G07 monitor chassis. There are two of them... a larger one (F902: main monitor fuse), and a smaller one (F901: flyback fuse). They're both soldered to the board, and when the flyback blows, it generally takes out F901. You need to be careful though... when that blows, it leaves high voltage on the large gray capacitor, which really hurts if you touch it. Be sure to discharge it first (put a screwdriver across its terminals... will probably make a loud pop).

Also, because of the voltage on the capacitor, if you try to test the fuse with a multimeter, a lot of times the fuse will read fine, even though it's actually blown.

To take the chassis out, you'll also need to discharge the CRT tube.

There's a lot of good info here: http://www.pinrepair.com/g07/ and http://www.therealbobroberts.net/g07repair.html .

Bob Roberts is closed at the moment, but he used to sell a repair kit with a flyback, cap kit, HOT (horizontal output transistor), and fuses ( http://www.therealbobroberts.net/g07repair.jpg ). I'd recommend picking all of those up if you can find a seller that has all those parts... your larger fuse is probably fine, and the HOT doesn't always blow, but they should be cheaper than having to ship it later when you realize you need it. ;)


You should still hear the game coin up, run, etc... even if the monitor is dead. If it doesn't, I'd double-check your cabinet fuses.

DogP


yes i agree and i do stock EVERY part so if cruiserandmax wants to add them to his order he can contact me and i would be happy to add it if its done before i ship today.
 
Bob Roberts would've been great if you like DOA G07 flybacks.

fortunately there's security now.
 
I am in the middle of replacing the caps right now and noticed that the old C517 cap that I just pulled was 220mfd 35v. The spec in the cap kit (and everywhere else I can find on the web) replaces C517 with a 100mfd 50v cap... My hunch is to just put in what came in the cap kit, but the question remains- what could it mean that I had a 220mfd 35v cap in C517? The game had been performing flawlessly for 10-15 years before the flyback recently broke...

(this is a G07 CB0 fron 1982)
 
Yeah, I'd install the 100uF cap (that's what the schematics call for). It may have been replaced at some point, or different rev, etc. Generally with large caps, the exact value doesn't matter a whole lot as they're just meant as bulk capacitance to smooth the voltage anyway.

DogP
 
Yeah, I'd install the 100uF cap (that's what the schematics call for). It may have been replaced at some point, or different rev, etc. Generally with large caps, the exact value doesn't matter a whole lot as they're just meant as bulk capacitance to smooth the voltage anyway.

DogP

Thanks for that- I also just noticed the cap kit came with an extra 220mfd 50V that is optional in C517 for the trapezoidal image problem that some technicians prefer to use. I guess some previous tech preferred it on this one.

Anyone familiar with that issue? From a brief search it seems using the 220mfd 50v in C517 may help that issue, and otherwise may not hurt anything..
 
Last edited:
Trouble desoldering flyback... ?

I have now replaced all caps, the HOT, and soldered fuses. But I am having a super hard time trying to desolder the flyback. The leads from the flyback are super thick, and the tip of my cheap desoldering iron with suction bulb will not fit down over them- and trying to heat/suck from the side of the pins isn't getting enough solder away from the pins.. Since there are 8 pins in a big circle there is also no real flexing I can do from the flyback side to help pull the pins when the solder is hot..

I'm thinking a real bench type desoldering iron with vacuum and tip wide enough to sit down over the giant pins might work- but I don't have one and they are pricey!

Any tips on getting this flyback out? That's all I have left to do.
 
Any tips on getting this flyback out? That's all I have left to do.

Remove the screws in the side of the flyback. ;) That's what it usually is when people think that they haven't sucked enough of the solder out.

DogP
 
Ha! That is a good call- I actually spent an hour or so thinking before I realized there were also screws! Unfortunately even after taking those out I think I still have soo much solder in the neck of the holes on all the pins that getting it all out seems impossible... uughh...

I've been re-adding solder/re-desoldering, but honestly I think I may be just getting even more and more soldered 'through' the holes doing that...

I really appreciate the reply!!
 
The board is just a single layer of copper (not plated through holes), so you're not getting any solder "in" the holes. I'd suck as much of the solder that you can, and then press the flyback pin toward the middle of the hole with the soldering iron.

The hole is a bit bigger than the flyback pin, and since it's not plated through the board, when you press it toward the middle with the hot iron, the little bit of solder that's left connected will melt and break free from the solder joint and the pin will just "float" in the middle of the hole.

DogP
 
If you really can't get it, if you cut the pin of the flyback really flush, you may be able to use your desoldering iron to suck more of the solder, since the pin won't be in the way. Or, if you have any local store that sells soldering stuff, you could grab a soldapult, which should fit over the pin.

DogP
 
Got it! Pushing on the pins with the iron for a while and also pulling from the other side eventually worked them all out...

The sad part: I triple checked all the caps were correct, swapped the HOT correctly, all the fuses, and got the new flyback in.... The machine is still not working.. I get cabinet fan and lights, but still no montior anything, and no game sounds :(.. At least the flyback didn't explode when I powered everything on this time:/

At this point I feel like it's beyond my ability to debug. Now that everything 'looks' good, I don't know where to begin..
 
Did you hear the static sound of the tube high voltage charging up when you turned it on? If you look at the back of the neck of the tube, do you see any neck glow (it's faint, so you may need to turn the lights out)?

If you have high voltage, you may just need to turn the "screen" control up (it's basically a brightness control, on the piece that you soldered wire from the new flyback to). The level will vary a bit between flybacks, and might just be adjusted too dark. Also, if you replaced the HOT, you made sure to install the insulator between the transistor and the frame, correct?

If you don't hear any life from the monitor, you should make sure you've got 120VAC. With your multimeter on AC volts, make sure you see approximately 120V across the two power wires going to the monitor. Obviously you need to be careful not to touch any of the wires yourself.

DogP
 
Back
Top Bottom