[SEDXC] Power Sipply Guru Needed

[JT Croteau]

Is there anyone in the club experienced in power supply repair who
could help me troubleshoot and possibly repair, if worth it, a power
supply I am having issues with?

Background:

I recently borrowed, with intent to buy, a TenTec Paragon from a club
member (see earlier post).  The rig came with an older model TrippLite
PR-25a power supply.  Neither had been used by Ed since he acquired
them and I'm the first person to use both in quite a few years. 
Before powering on, I inspected both internally quite well to make
sure nothing was loose and no components were leaking or obviously
damaged.  However, when I first powered on the power supply, it came
on with a "bang" sound but voltage output was a stable 13.82V so I
fired up the rig.  The rig appeared to work fine but I was plagued
with some very bad electrical interferance that made reception
impossible.  Tonight, I removed my car battery and brought it in the
shack and the noise I've been experiencing is gone completely and
stations from all over started filling my receiver with my antenna
still laying on the ground.

So, something is wrong with the power supply but I am not sure where
to begin to troubleshoot the problem or if it is even worth it. 
TrippLite refuses to give me any schematics for the PS so I am not
sure what to do.

Any help would be greatly appreciated as I can't go out and drop $150
on a new power supply right now.

Thanks

- JT (W6FO)