Thursday, February 28, 2013

Fixing a Samsung SCX-4725FN laser printer

My friend called me about a Samsung multi-function laser printer that didn't wanted to properly power on anymore. I said that I don't know anything about printers, but that it sounded like a PSU fault (as always...) and that he could try to google it. After just a few minutes he sent me this link, apparently describing more or less the exact same problem that he had. So I said, sure, if it's only a cap I can always take a look at it.

Said and done, I opened it up and here's what I found

The PSU at the back of the printer. The faulty cap in red square.
The faulty swollen cap in red square.

 It was identical to the one pictured at Flickr. The PCB was brownish around the cap indicating heat from the resistors. As this wasn't enough, the poor cap must also tolerate heat from the heatsink right next to it. No wonder it can't hold up for too long (this one about 5 years). On the other hand, it wasn't the worst cap model available that is normally rated for 85 degrees Celsius, but a slightly more tolerant, rated for 105 degrees C and 3000h.

The cap was easily replaced with a new one, this time with one that should withstand 105 degrees C for 10000h. I think something else will brake before that next time the printer fails ;)
Below is the result.

New better cap in place.

Printer up and running again.

1 comment:

  1. Hello~
    My printer is the same issue so I wonder where I can purchase that capacitor(black). Please let me know.
    boss9293@gmail.com

    ReplyDelete