[R-390] R390A Problem

[Chuck Rippel]

Hey, I am a Drake person also.  My first "store bought" radio was a "C" Line.  
I just finished re-doing a very late model "C" Line for myself and its near 
factory perfect.

With regard to the blocking cap the problem does not occur every day but its 
very destructive when it does.  I happened to me about 12 years ago and I 
lost a 4kc filter to it.  

If you want some additional background, go on my R390A WWW Site and 
look at:
http://www.r390a.com/html/C-553.htm

It describes the cap/filter problem in detail.  Replace the original cap with a 
600V .01uv SBE Orangedrop.  If you don't have one, send me a 2 bucks and 
I'll mail you one.  Orangedrops work great at 455kc and below.

You can tell who built the radio by looking at the mfg markings on the side of 
each module.  The contract/builder history is here:
http://www.r390a.com/html/Ordernumbers.htm

Tom Marcotte N5OFF sells generic front name plates. I am sure someone on 
the list has his current e-mail address.

I'd enjoy an off list discussion about Drake if you get the chance.

-73-

>If you guys will let a Drake man in here... :-)

> I just picked up a well-used R390A that hasn't been powered in 10+
> years (yes, I have a variac).  I've been reading a lot of stuff on the
> web, and noticed several notes about the cap that shorts and destroys
> the mechanical filter(s).  How prevalent is this?  I plan to replace
> the cap anyway with a higher voltage rating, but I was wondering if
> anyone has looked into methods of protecting the filters.  I was
> thinking, maybe a small-value pico-fuse in series with the cap?  It
> seems at that frequency, it would have negligible effect on circuit
> operation.  I've seen them as small as 1/8 amp, would that be small
> enough to blow if the cap shorted?  I have no idea at this point of
> potential current involved, just idle speculation.

> Is there an easy way to tell manufacturer and approx. age if the
> nameplate has been removed?  Who's the guy that sells replacement
> nameplates?



-----------------------------
Chuck Rippel, WA4HHG
R390A List Co-Administrator
Reply to: R390A@R390A.com

To learn more about R390A's visit:
http://www.R390A.com


1968 Contract Dittmore-Friemuth R390A #38
1967 Contract EAC R390A #2808 with outboard Sherwood SE-3 Sync. Detector
1967 Contract EAC R390A #5295
1967 Contract EAC R390A #5591
1967 Contract EAC R390A #1023

All in regular use as premier Shortwave Broadcast DX Receivers
       -and-
Vintage AM Amateur use
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