• Home
  • Help
  • Search
  • Login
  • Register
Pages: [1]
Author Topic: I fixed my Sheeva's power supply (pics, howto)  (Read 1568 times)
dattaway
Jr. Member
**

Karma: 5
Posts: 91



View Profile WWW
« on: September 24, 2010, 07:10:28 PM »

I hope this may help those who have soldering skills and want to try their own repair.

My plug's power supply finally quit after a year of solid uptime.  It started with a reboot a few weeks ago, then again several days later, then increased in frequency...  It was an obvious power supply problem.  I took it apart and I found three bad capacitors:



From left to right: 1) 400V, 6.8uF, 2) 400V 22uF, 3) 1000uF, 10V....

This is the power supply.  It was wrapped inside an insulator within a box within another box.  Three easy to replace capacitors evaporated their electrolyte from the heat.  The two on the left were rated at 400 volts, but I had 200 volt caps and that's fine since we are on a 120 volt service.  (120 volts peak to peak is around 180 volts...)  The left was a 400V, 6.8uF and the middle was a 22uF.  I replaced those two with 33uF.  The diodes and fuse have no problems handling the extra capacity.  The real problem was the one on the right, which was 1000uF at 10V.  That one was completely toasted.  I had a 1000uF at 16 volt on hand, which fit well.  These capacitors are polarized, so + and - had to be on the correct side or they could explode.



I placed the power supply back on the housing shell without the protective boxes for extra ventilation.  I also bent a plastic tab back to help with air flow to the external vents.  Doing this may be a bad idea, considering bad things may happen if the power supply gets knocked around and touches the sheeva motherboard.

The motherboard itself was of outstanding quality and construction.  The power supply not so much.  It was more like a cheap off the shelf consumer power supply made to work.  This repair should give more life.
« Last Edit: September 24, 2010, 07:12:43 PM by dattaway » Logged

andebkr
Newbie
*

Karma: 0
Posts: 3


View Profile
« Reply #1 on: September 24, 2010, 10:45:05 PM »

That one seems to be a good one that would be a solution to many of the problems. The power supply has become a necessity these days. The pictorial presentation just provided a better view of the things and have a better idea of how you fixed the things up. Thanks for sharing it here.   
Logged


dattaway
Jr. Member
**

Karma: 5
Posts: 91



View Profile WWW
« Reply #2 on: September 24, 2010, 11:18:29 PM »



Here's a picture of the old 1000uF blowout.  The safety vent on top failed and almost launched like a rocket.
Logged

Pages: [1]
Print
Jump to: