[LAU] OT: Behringer PSU UB-SPSU2 for an Eurorack UB2442FX-PRO

gene heskett gheskett at wdtv.com
Tue May 8 16:47:24 UTC 2012

On Tuesday, May 08, 2012 12:36:57 PM Ralf Mardorf did opine:

> Hi Gene :)
> On Tue, 2012-05-08 at 11:13 -0400, gene heskett wrote:
> > On Tuesday, May 08, 2012 10:32:50 AM Ralf Mardorf did opine:
> > > When I turned on my 7 year old Behringer
> > 
> > Using its age as a clue, I think I would be gong through it with a
> > "Capacitor Wizard" checking the caps in the psu in particular.
> I guess I already found the problem. On the primary side there are a 1u
> 50V and a 47u 25V capacitor, both 85آ°C. Thomas said I should replace
> them with > 100آ°C, even if they look ok.
> I've got capacitors on stock, but bad equipment for soldering. Unsolder
> already was hard, but I can't get it soldered, especially since the 47u
> I've got, has got a larger diameter, since it's a 35V. Reading glasses
> btw. are less good for soldering, I need to find a better tool to see
> when soldering. Thomas has got some special glasses.
> > I haven't a clue what it may be called on your side of the pond
> > though, so I will describe what it does in hopes it might be
> > recognizable as a euro made and named testing device.
> > 
> > It is a small, low power oscillator, generating about 85 millivolts of
> > rf signal, at a nominal frequency of 100 kilohertz, the currant it
> > can send through a capacitor is presented on a meter, usually
> > calibrated with a knob so that it reads full scale when the probes
> > are shorted together.
> Thomas has got Hameg oscilloscopes with component testers.
This thing, because of the very low level of signal used, does not 'turn 
on' any semiconductor junctions, so they disappear from its view.  That 
means you can do a very reliable test while it is in circuit, before you 
warm up the iron.

When I took a chance and spent $175 of the tv stations money for it, close 
to 20 years ago now, I was initially a little dubious, but that thing has 
turned out to be worth at least as much as sliced bread or bottled beer, 
and has probably saved me many hundreds of hours of troubleshooting time 
since.  That, a good temp controlled iron, and a good scope (and the brains 
to see what its telling you) are the 4 most indispensable tools a techie 
can have.  I left out the dvm because everyone has one of those today...

> Btw. the capacitors I unsoldered are broken now, even if they should
> have been ok before. Not because of heat, but to take hold of the
> capacitors damaged them.
> > Having a spare for that sort of thing is a good idea.  Asking if it
> > will fail is like asking if freshly poured concrete will crack.  The
> > "if" is wrong, the correct word is "when", because it will, always.
> > :)
> I'm not a fan of switching power supplies.
> > Good luck Ralf.
> > 
> > Cheers, Gene
> Thank you Gene, Thomas tries to visit me in some hours.
> Ralf
You are welcome.  I hope I helped.

Cheers, Gene
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