pcb repair on PSU

Discussion in 'The Projects Forum' started by electronis whiz, Jun 10, 2011.

  1. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
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    i have a psu and 3 of the leads on the bridge rectifier were disconected from the pcb along with the solder pad. whould it be ok to just melt some solder along the trace then conect it to a terminal of a diftrent part. or can i just scrape off the solder mask thn solder there. my concern with runing the solder to a difrent terminal is the current would heat it up melt it and make a short. is this somthing i need to wory about? if i can remove the solder mask what would be the best way to do that?
     
  2. jj_alukkas

    Well-Known Member

    Jan 8, 2009
    751
    5
    How did it melt off? Spike or something? Then there is a good chance that you have a browned bridge. The leads might have melted as a result of short circuit and them acting as a fuse. Check the bridge if its working properly and not shorted. If everything seems ok after testing, you can retrace the connections using pieces of insulated wires as there is a good chance of the lead melting if this rectifier is for above 1A. Using wires is safe, just solder them to terminals instead of the missing tracks.
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Make certain that the filter capacitors that the bridge connects to are good. If they are bulged even slightly, they are bad. Bridges don't typically fail unless they are put under a heavy load, and bad (shorted) capacitors would be a heavy load.

    Solder is a relatively poor conductor compared to copper. If you need to bridge a failed area, use either some flat copper stock or copper wire to carry the majority of the current.
     
  4. ErnieM

    AAC Fanatic!

    Apr 24, 2011
    7,389
    1,605
    You can usually just scrape away the mask with an exacto if you are careful.

    Did this part get dropped and the pads break off, or did the leads melt away? If the melted away then they will melt away after you solder them back, there is another problem lurking.
     
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  5. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    i picked this psu up at an auction. it didn't turn on when tested so i opened it up saw that 3 of the 4 terminals on the bridge were disconected from the traces with the pads atached like it got pushed down on. i got it working by runing some wires around the psu i just think there is a better way. it is clear and lights so it looks wierd too with all this wire.
    i just want it to look like new.
    (the waranty was done and i didn't get it new so i just fixed it myself. it was in the original box and logisys is a mid grade brand)
     
  6. electronis whiz

    Thread Starter Well-Known Member

    Jul 29, 2010
    519
    27
    that is what i wanted to do is just solder direct to a trace. do you think i could just melt the mask off with a solder iron?
     
  7. Adjuster

    Well-Known Member

    Dec 26, 2010
    2,147
    300
    Don't just try to burn your way in with the iron - you'll probably just detach more track that way. I think you would do better to follow the earlier suggestion to scrape down with a small sharp blade to expose the copper
     
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