Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

 
 
LinkBack Thread Tools Search this Thread Display Modes
Prev Previous Post   Next Post Next
  #1   Report Post  
Posted to sci.electronics.repair
Don Don is offline
external usenet poster
 
Posts: 44
Default Dual output supply dead

Hi,

I use a lot of external disk/tape/etc. enclosures or
my computer peripherals. These typically have ~60W,
dual output (5/12) supplies in them.

They are a "popcorn part" so, when one fails, it is usually
easier to grab a spare out of my junk pile and replace the
entire power supply than waste time trying to repair it.

However, I have one such supply that is dead AND has an
atypical form factor (long and skinny). So, finding a
suitable spare in my junk pile has been a problem :
(the supply in question is a Autec UPS65-2002) It is
functionally equivalent to the dozens of other supplys
that I have so I have temporarily replaced it with one
of those.

I figured it might be worth a few minutes to poke around it
and see if I can steal some components off another supply
to breathe new life into this one. (If not, I'll just pull
the disks/tape out of the enclosure and throw the whole
thing out in favor of another enclosure).

A quick look at the types of components on the PCB leads me
to make some guesses as to what the circuit topology is.

It looks like mains power passes through an input filter
(choke, snubber, etc.) and then rectified. Switching
transformer primary is chopped and controlled by a sense
winding on the xformer. "Center" tapped secondary (no doubt
assymetrically tapped) two legs are rectified and then LC
filtered to provide the final output. I assume some sort
of OVP watches one or both outputs as I see optoisolator
feedback across the transformer no doubt to shutdown the
chopper.

Can someone confirm my guesswork to be correct?

Nothing is visibly toasted. And, assuming this topology,
I'd guess the chopper is "opened". Of course, it is possible
that there is a failure elsewhere on the board/load but I
suspect it may have just opened from fatigue, etc.

I.e. is it worth hunting down a replacement part (out of the
scrap bin) for a "quick fix"? Or, are these a bit more
complicated to repair (in which case, tossing it all in the
hazardous waste recycling bin is more expedient).

Recall I am *not* particularly "attached" to this enclosure... :

Thanks!
--don
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Sony GDM-FW900 power supply MCZ3001D info needed Andy Cuffe Electronics Repair 4 August 18th 06 07:05 PM
PowerMac G4 (Quicksilver) Power Supply Chris Electronics Repair 7 January 31st 06 03:19 AM
dvd power supply dead bigtom Electronics Repair 4 July 1st 05 03:58 PM
Power Supply Repair fernando1222 Electronics Repair 0 June 7th 05 09:18 PM
Converting old PC power supply to hobbyist PSU Adam Preble Electronics 0 February 27th 05 07:43 PM


All times are GMT +1. The time now is 04:00 PM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"