Saturday, 6 September 2014

Delta sadp-65kb

 Wolumen is one of my favourite places in Warsaw. You could even call it Europe's Huaqiangbei, poor man's SEG, 2 hectares crammed with electronics. Basically its like Hamfest, but 52 times a year plus permanent shops open all week.

 Sometimes I pick up broken crap there. Mostly because Im curious, for parts, or to fix. Recently I got this Delta sadp-65kb laptop power supply, it cost me a whooping $1.

 I couldn't sleep and decided to fix it at 3 in the morning :/ Best place was of course my bed, using 25 year old soldering iron and $3 multimeter :)

 Something bad happened on the input side and shorted rectifier bridge. Fuse blew after the fact.

 Yes, this is a 3.15A fuse in a 65W box, gotta love Chinese engineering :) I replaced rectifier with one salvaged from old ATX PSU, soldered power cable directly to rectifier and powered it up. Success, well that was easy!
 I put it back together properly, checked again and nothing, Murphy strikes again. Turns out banging with a hammer for 5 minutes to break ultrasonic plastic welds of the case is not a recommended procedure :o). Note to self - next time use vice to slowly crack case open. I whipped my magnifying glass and discovered almost every heavier part had cracked pads or solder joints, and common mode choke was hanging on one wire. You can see cracked pads below, 100 ohm resistor partially resoldered.

 Another 10 minutes scratching solder-mask and reinforcing solder joints, then putting choke back on its place.

 Back like new.

  Time for thermal compound under rectifier and some wood glue (PVA) for structural strength. Done.

 45 minutes to fix $10 power supply, not the best bang for your buck. On the other hand smell of flux fixed my insomnia.