dead doepfer ps help

[jh.]

> Gee, thanks for the help.  I guess you're saying that using doepfer equip
is
> bad for diy?  Whatever.  The reason I'm posting to this list is that I
> recently built a nice big cabinet to house my doepfer modules so I can add
> blacet, paia, and hopefully some diy stuff.  Unfortunately I'll need some
> help since I'm a musician, not an engineer, but I guess this list isn't
the
> place to look for that help.

It should be. *Even* when you need help on Doepfer stuff.

(But then again, does Mr. D. provide no custumer support, other than
selling replacement modules ? Hmm, I once bought a Midi Interface
kit from him many years ago, with one chip being the wrong type,
but instead of apologizing and replacing the chip, he told me to send
back the complete kit, which would have meant another 2 weeks of
waiting - so I rather bought it in a local shop on my expenses.
Early pre-shaping of my opinion towards that company ...)

> If anyone out there does have the heart to give me some advice, here's the
> problem:
> When I put in a new fuse the power supply turns on for a second and then
the
> leds fade out almost immediately, and the fuse is burnt out.  Does that
> sound like the circuit is just dead, or is there any chance it's some kind
> of grounding problem?  My cabinet is made of wood, so I just tried to
attach
> the ground lug to the metal frame that the power supply is bolted on.
Would
> that have fried the supply?  I really do not want to have to buy a new
power
> supply if there is just something dumb I'm overlooking.  I also wouldn't
> want to buy a new ps and fry it as well if there is some grounding issue
I'm
> overlooking.  Any thoughts would be greatly appreciated.

I'm not familiar with that circuit, but one thing is for sure: *Isolate* the
problem,
i.e. disconnect the power supply from the rest of your synth before you try
anything else. Because:
A) You don't want to risk blowing the rest of your synth
B) You will see if the problem is in the PSU or if some module has a short,
draws too much current, etc.
If it's not the PSU, connect the modules one by one, and see when the error
occurs.
If it's in the PSU, look for shorted tantal caps, blown regulators etc.

And (meant seriously, despite my snide remark from above): Ask the
manufacturer, he should be familiar with "typical" errors of his product,
which often helps you save a lot of time. (I just had a problem with
my Fostex R8, and their service department immediately told me
which would be the error in 90% of cases - and right they were.
Great customer support, Fostex !)

BTW, I can't see any problem from your connecting GND with the
chassis (unless Mr. D. connects it to one of the supply rails internally,
which I seriously doubt ...), so don't be shy and let yourself being
talked into it being your own fault. Dare I ask if you still have warranty ?

Good luck,

JH.