[R-390] F103/R390a

[Joe Foley]

Do the resistance checks in the manual especially the
wiring harness.  It may be the input filter, maybe bad
caps in there?  Then unplug all the modules and see if
the fuse still blows with just the wiring harness
hooked up.  It might be a good idea to put a light
bulb in series with the hot line, just so that blows
instead of something expensive.

Check tubes for shorts.  If the wiring harness shows
no problems try plugging in each module with no tubes
in it, start with the power supply, of course.

It could just be too much in-rush current.  Is your
line voltage a bit too high?

Joe




--- Jon <jonklinkhamer at comcast.net> wrote:

> Hello to the group,
> 
> I recently finished up my rf deck and reinstalled
> it, upon powering up the
> radio I noticed I was blowing the 1/8 fuse
> (F103)every time I did a power
> cycle. After disconnecting P108 (RF Deck),P109
> (PTO), P110 (Xtal Osc)and
> P512 (IF module) I am still popping the fuse.
> According to the schematics
> the label is the "RF-IF B+ lines. My thinking is
> leading me down to the S102
> switch (the power on/AGC/Cal switch). Does anyone
> have any ideas.
> 
> Thanks,
> Jon, KB1DC
> 
>
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