Stargate power supply blowing f3 fuse

Bax

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So picked up a Stargate a couple days ago and started to dig into it today. Was not getting 12v so checked fuse and f3 was blown. Changed fuse and had 12v but 5v was low. Pulled power supply out and colder solder joints on header pins. Now f3 blows every time. Can't find any schematic on power supply. Oh, also put in a new 2n3055 transistor
 
i have a complete rebuild kit and also a cap kit with stuff that fits all 105c even the large axial cap included. i have kits for the D8784 and the D8359 both which covers all the older williams games. way better caps and higher rated parts then any other vendors kits i have seen out there.
 
Could there be different power supplies? Mine doesn't look like that. I have a big heat sink below it for the Fett transistors
 
Stargate either came with the Defender power supply (where everything is mounted on one board) and came with another board that goes between the main power plug (this was Williams' way of adding overcurrent protection; without it, if the 2N3055 ever failed (+12) it would dump 24 volts into your board -- or it came with the later model power supply that is commonly found on Robotron or Joust.

both power supplies use identical components, they're just laid out differently and the later model one has overcurrent protection built in.

older model has the 6057 transistor on the larger heatsink and 3055 on the small; on later model the top transistor is 6057 and bottom is 3055.

if your +5 is showing low you can try reseating the 6057. either that or I think the smaller bridge rectifier could be bad, or the caps are rotten, or you have a blown trace somewhere.

I would replace the headers, the factory ones aren't good. you probably observed that solder doesn't even stick to them well. if you're consistently getting blown fuses now I would encourage going back over your solder work.
 
Could there be different power supplies? Mine doesn't look like that. I have a big heat sink below it for the Fett transistors

Mine came with the later Joust power supply. See if this is it.

http://arcarc.xmission.com/PDF_Arcade_Williams/Joust_Drawing_Set_(16P-3006-103)_Sept_1982.pdf

I have worked on a bunch of their pinball power supplies and would test if the BR2 for the 12V supply is shorted as a quick check. Some rebuild kits don't have BRs in them so ask but a rebuild is something that is a good idea including connectors.

On the Joust supply the 4J4 jack and 4P4 plug can kill/flake out the +5 and +12V (go to the heat sink) and of course the connector from Transformer 4J1 and 4P1 is critical to having good voltages at the test points. Then there are the output connectors etc.

Kenny
 
Mine came with the later Joust power supply. See if this is it.

http://arcarc.xmission.com/PDF_Arcade_Williams/Joust_Drawing_Set_(16P-3006-103)_Sept_1982.pdf

I have worked on a bunch of their pinball power supplies and would test if the BR2 for the 12V supply is shorted as a quick check. Some rebuild kits don't have BRs in them so ask but a rebuild is something that is a good idea including connectors.

On the Joust supply the 4J4 jack and 4P4 plug can kill/flake out the +5 and +12V (go to the heat sink) and of course the connector from Transformer 4J1 and 4P1 is critical to having good voltages at the test points. Then there are the output connectors etc.

Kenny


my rebuild kits have EVERYTHING in them. cap kits are on my site and the rebuild kits are going on tonight later when i get some time.
 
Some good info guys. It is the joust power supply. So the Fett transistor I changed out blew. So wonder what is blowing that. I am going to repin it as well
 
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