Street Fighter II Power problem (Gottlieb System 3)

[Belac]

Hi Guys,

I'm new around here, been researching machines as I'm looking to buy a project machine in the next 12 months or so. My father in law (to be) has a SFII machine that has reminded me how much I love these things. I played Star wars and TAF to death at my local arcade 15 years ago.

Back on topic, the SFII machine wouldn't boot up last weekend, the general illumination lights light up, but no sound, and the DMD shows nothing but a 15 - 20 random dots that vary each time its turned on. I've been reading the guide at www.pinrepair.com, as well as the PDF manual I found, which has armed me with heaps of knowledge but not quite enough!

At first I thought it was just a display issue, and after checking all the fuses, I re-seated all ribbon cables in the backbox to no avail.

I then checked the voltage running to the Control Board (A1) to see whether it was within the acceptable range, and found there was no power there at all.

Closer inspection (which still has me baffled) found that fuse F5 was blown, which supplies the Aux power in the backbox. Replaced the fuse and it burnt as soon as the machine was powered back on.

No LED's are lit on the boards in the backbox, so as per the repair guide I've powered the Control Board with an external 5v supply, and all LED's on each board in the backbox flash and behave as normal, so I'm assuming the problem lies elsewhere.

After burning many fuses i've built a little breaker with fuse ends on it as per the thread in the tips and tricks forum (very handy). This now 'breaks' every time the unit is switched on. I also disconnected the A5 and A2 boards in the backbox from the loom and tried turning the machine on (thinking one of the aux power boards was shorting) and the breaker still breaks.

I'm going to read the entire pinrepair sys3 section today, as I've only read certain sections so far (display issues, power supply) but if any assistance would be appreciated!

Failing that i'm going to need to get a tech in, I'm in Geelong if anyone has and recomendations.

Ohh, and i know it's not the most popular title getting round, so please no repllies saying 'burn it to the ground' !

Cheers!

[humpalot]

Fuse F5 is directly connected to the 12V bridge in the bottom of the cabinet.  A faulty bridge will cause the fuse to blow.  You need to check the related bridge and replace if faulty.

[Pinball Fixers]

Humpalot is correct - a faulty Bridge Rectifier is the most likely cause.

You can replace this with a 400V 35A (or higher) rated bridge. Jaycar and other electronics parts shops usually have these. Don't bother with Dick Smith any more as they only sell consumer electronics (TV's, DVD players, etc...) and not electronic parts.

[Belac]

Excellent thanks very much guys!

Just picked up a 400V 35A bridge at Jaycar during lunch. Was only $4.45 so I'll have a look when I'm over there later this week.

As I'm not at the machine currently, is this a solder job or a plug in replacement?

Also, if i'm not asking too much where is the bridge located in relation to this pic? and is it difficult to tell which one fuse feeds F5?


Thanks again for your help.

Caleb.

[dj10555]

Hi Caleb,

Would you be able to post some more photos of the bottom of the cabinet so they show the rectifiers?

regards Derek

[Belac]

Sorry Derek, last weekend was the first time I opened the cabinet so not really sure where they are hence me asking!

That image is not mine, but i've found another which look to be the rectifiers, answers my question about solder too.



Just trying to arm myself with enough knowledge at this stage. I should be able to trace the fuse back to the relevant bridge. I'm about to start looking how I can test the existing one before i start cutting wires and getting out the soldering iron..

[humpalot]

OK looking at that pic the bridges are in this order
1st is 48V
2nd is 20V
3rd is 12v

You will need to solder on the wires in the correct places on the bridge.  Also some heat joining paste needs to be applied on the bridge before it is screwed down onto the metal plate.

[Belac]

Awesome thank you very much. I'll double check my machine as that is a photo i found on the net.

I'm now know how to test a bridge rectifier with my DMM, and we have some thermal paste at work for PC CPU's.

Thanks everyone for the help so far!

[Belac]

Back again..

I've replaced the bridge, the old one was faulty.

Turned on the machine, and all LED's in the backbox are were hard on. But nothing on the DMD.

Turned off, disconnected the control board, powered back on and re-checked the 5v from the aux power supply, it was 5.3v so adjusted it back to 5.05v.

Currrently still has nothing on the DMD, and now all LED's are hard on except the 2 sounds boards, which are off.

pinrepair indicates it might be the U8 GAL chip, is it worth sourcing on of these?

[studley67]

keep at it sf2 is worth fixing.i have one and proud of it.sorry cant help with the dmd,havent got a clue but try unpluging the sound board.

[Belac]

Definitely worth fixing, I find it a very enjoyable game even though it's rule set is somewhat different to the norm. Keeps me going back for more anyway!

Tried unplugging the sound boards but no luck..

Might pull out the 20v and 48v bridges and test them, unless someone has any other ideas?

[Belac]

Frustrating, but worth it for knowledge gained.

Had a tech come over on Saturday. Paul from Timezone Geelong, who also does the repairs at Bike City.

He inspected my bridge replacement and was happy, checked for 12v coming into the aux power supply, and then started testing voltages on the DMD. He found 3.8v instead of 5. A quick (blind) twist of the trim pot on the aux power supply and it booted up, I was so close yet still so far.

I had tested for 5v coming into the CPU board, but i was removing the connector from the board, so I assume I didn't pick up the low voltage due to it not being under load?

I had also read that there is no over-voltage protection on the boards so was a bit scared of cranking up that trim pot, didn't want to fry anything.

While he was there he went over the playfield and showed me how to fix a faulty coil, and how to test the coil & diode assemblies. So it was worth it just to gain a bit more knowledge.

Everyone concerned was happy to see it going again, about to buy a rubber kit and give it a birthday, could do with a good clean too which i'll do.

Cheers for all the help, much appreciated.

[Strangeways]

Great to see your machine working again ! It is very rare to see faults on system 3 machines. They are very reliable. Don't get rid of SFII - It is an awesome machine. I wish I never sold mine, but I'm happy that it went to a good home and is part of a great collection 

[silverball]

Great to see your machine working again ! It is very rare to see faults on system 3 machines. They are very reliable. Don't get rid of SFII - It is an awesome machine. I wish I never sold mine, but I'm happy that it went to a good home and is part of a great collection 

Just picked up another streetfighter Nino, do you want to buy it .

Agree, system 3 gottliebs are usually reliable and I dont mind the streetfighter game myself.