View Single Post
  #7   Report Post  
William R. Walsh
 
Posts: n/a
Default Help Needed With PC Switchmode Power Supplies

Hi!

Read time=money. IN other words, can you afford the time to trace
out the schematic?


I don't know...depends upon what people are asking for their time and how
badly I really want to know why these things died. (And I want to know that
pretty badly. Obviously any proposal to look at it has to be
reasonable...but beyond that...I just want to know why they died.)

The compounding issue is that there is nothing that requires the power
supplies to use the same design.


For most power supplies I'd agree with you, at least to an extent. However,
the PS/2 Model 95 line used this same Delta 335 watt supply across almost
the entire model line. I've seen a lot of them, and all are the same inside.
Even the 400 watt unit is largely the same inside...key differences I see?
The fan speed on those varies in operation, circuit boards are a different
color and the heatsinks might be a bit thicker, but that was all I noticed
right away. The point is that these were a custom-built, standardized
design. As far as I can tell they did not change the design much--if at
all--during the lifetime of the PS/2 Model 95.

I've only ever seen one that was *not* made by Delta Electronics.

I might disagree with you on the frequency that this scenario will occur. I
know others who have power supplies just like this that have died. This is
what is so alarming to me...most of these machines just run and run. The
Model 95 and its 335 watt supply seem to be the exception to this rule. I've
got at least two or three here now that have all failed with the same
symptoms--they're just dead.

William