Sega Star Trek blowing fuse in junction box

Dick Jones

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Pin 4 on the power supply is receiving too much current . Basically, with only the power supply connected. Upon plug in pin 4 frys and the junction box fuse blows. Please help
 
Most of the pin 4 connections are grounded on the schematics I have from mikearcade. There is a pin 4 for 220v ac input to the transformer and there is a pin 4 for the audio out I think.

Since this is blowing fuses I would do a diode test on the bridge rectifiers.
 
thanks for replying

sorry - power input pin 4 melted jack to pin, jumper from pin 4 to pin 6 actually blew off.should we replace the jumper or try without?

tested all diades , regulators, transistors, capacitors, (DCR-ESR) and no dead shorts , same results with two different power supply, one supposedly tested and working. WTF the board has a slight discoloration but thats it.
 
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sorry - power input pin 4 melted jack to pin, jumper from pin 4 to pin 6 actually blew off.should we replace the jumper or try without?

tested all diades , regulators, transistors, capacitors, (DCR-ESR) and no dead shorts , same results with two different power supply, one supposedly tested and working. WTF the board has a slight discoloration but thats it.

can you post a pic of the power input pin 4 with the melted jack and any all damage. I then may be able to help you much better.

I hope you don't have that set for 110vac and powering with 220vac!
 
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Pm: sent 2 Ya

sounds 2 me like the transformer is you problem. Either it is connected improper or it is shorted at the input/output. If it is not at the transformer then it is near by it.

look at page 148 of the pdf from mikesarcade.

input pins 1 is your common then you apply power to the correct pin 2 for 100vac, 3 for 115vac, 4 for 220vac.
 
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Pin 4 on the power supply is receiving too much current . Basically, with only the power supply connected. Upon plug in pin 4 frys and the junction box fuse blows. Please help

I just re read this and I think you are putting the 110vac to pin 4=220vac, that could cause a problem.
 
thanks!

ill post pics of everything ASAP. my window of time to "play" with this has passed. try and get everything up by tomorrow evening. thanks for your help. hopefully we can troubleshoot.
 
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