Most likely some kind of failure in the rectification and
filtration electronics of the power supply. Probably a cold solder joint
or a bad filter cap. I would offer to fix it for you if you sent it to
me but I doubt you would want to send it to Hawaii. However I AM very
curious about its behavior and what is causing it.
is beginning to sound similar to a problem I have with a "new" (two years old,
but never used) 12v Pyramid 10a regulated power supply.
I use this PS, any DC power cable hooked up to a DC output (screw terminals or
the front cigarette lighter socket) heats up very quickly to the point where I
can't touch it. And the back of the PS where there are two external
transistors mounted, gets hot very quickly too.
when I attempt to plug the DC end into something (such as a video monitor or
video camera), there's a little spark between the plug
and socket when I first plug it in.
didn't catch any of this the first time I used it -- and it apparently fried
one of my monitors. I've also melted two DC power cables in
testing. No fuses have ever blown.
I do simple tests for voltage and continuity, everything checks out OK.
No shorts, no reversed polarity, and the voltage is 13.89v
there's most definitely something wrong with the PS. I'm thinking that
testing for the problem is beyond my skills. So I've put it in the tub
for electronic recycling.
I do have an old Fluke 77 and a brand new Fluke 115. So maybe I have the
proper tools, just not the knowledge to use them to figure this problem
already purchased a new PS, but I haven't yet put the suspect PS in electronic
recycling. If there are some relatively simple tests I can perform with
either of my Fluke instruments, maybe I can get to the bottom of the problem
and "save" the otherwise brand new PS.
Use a voltmeter to measure what voltage difference exists
between the laptop's chassis ground and the CP4's chassis ground. NOT
the ground pins of the AC power cords.
However spurious ground differentials will only exist when
the CP4's power is connected and disconnected. They will probably be
fast and only detectable by a O-scope, analog meter or a digital meter
with an analog scale, like a Fluke model 77.
Running the CP4 from a battery will isolate the CP4
completely and guarantee that a spurious ground differential can't come from
I still say the CP4's external power supply is the #1
how to test it? My only test destorys laptops?
running your CP4 off a 12 volt battery. That would confirm that something is
flaky with your Dc power supplies.