Michael,

really strange that the problems occur after a couple of months and with
several systems at the same time. Here is my suggestion (I assume that your
A-100 frames include PSU2 with the toroid transformer):

The 500 mA value is based on the recommendation by the the manufacturer of
the transformer. Though it never happened in our company we've been told
that the 500 mA fuses blow now and then during power on because of the
transient current (never while the unit is on for a while). That's why we
increased the recommended fuse value to 630 mA in the meantime (315 mA for
230V systems). I'd recommend to replace the fuse by 630 mA or the next value
you can get (even 750 mA would be OK). The value is not that critical as in
case of a short circuit even a fuse with a slightly higher value will blow.

And it's essential that a slow blow/time lag fuse is used. Fast or medium
fuses will blow during power on because of the transient current.

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com
> [mailto: Doepfer_a100@yahoogroups.com ]Im Auftrag von michaeltritter
> Gesendet: Mittwoch, 6. September 2006 06:03
> An: Doepfer_a100@yahoogroups.com
> Betreff: 1 g6 fuse problems
>
>
> Wondering if Dieter or anyone can help with this one:
>
> I've had 3 G6 racks for a couple of months. None of them have
> been problematic until
> yesterday, when one of them blew a fuse. I replaced the fuse, and
> everything worked
> again, until today, when the fuse blew again. I removed most of
> the modules, and the fuse
> blew. I removed all of the modules, and a fuse blew. I then
> tested one of the other cases
> by turning it on a few times, and eventually one of those blew
> too. I have tried different
> surge protectors, different cables, different electrical circuits
> in my apartment -- same
> thing.
>
> It would seem that this would indicate either 1) some major
> problem with my building's
> electricity (possibly but unlikely), or 2) two G6 power supplies
> that went defective at
> exactly the same time (possibly but unlikely).
>
> Any thoughts If it is some crazy problem with New York city's
> electrical grid, I would
> imagine the Doepfer racks wouldn't be the only things
> susceptible. But the fact that two
> different boxes, tested with all different numbers of modules
> (none, a few, a bunch, and a
> lot) kept blowing seems downright weird.
>
> I am using 1/2 amp slow-blow fuses, and tested the outlets in the
> apartment, which are
> all running pretty close to 115v (~117, ~120, etc.).
>
> Is there something completely stupid and obvious that I'm missing
>
> Thanks anyone for any help.
> Michael Tritter
> New York City
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