[R-390] Re: Replacement C-551

Tue, 24 Dec 2002 14:42:01 -0500

Richard,

There does not seem to be an exact fit new component (C-551) available.  If 
you desire exact fit, you might try Fair Radio Sales for a used part.

You can keep a semblance of original appearance (topside anyway) by 
disconnecting C-551 and leaving it mounted in original position.  A compact 
modern replacement component can then be installed under chassis.  The SBE 
Orange Drop series capacitor seems to be preferred by many on this list, but 
other caps will certainly work.  I prefer the Cornell-Dubilier (CDE) DME 
series (available from Mouser Electronics) because its small size simplifies 
installation.  I have cut the leads on these to about 1/8" and secured the 
part to the C-551 side of the underchassis partiton, leads facing out, using 
RTV.  The leads removed from original C-551 are then wrapped and soldered to 
the 1/8" stubs on replacement C-551.  While you're at it, the .1 uF cap 
going from one side of C-551 to ground can be replaced with a modern 400V 
(or better) rated unit.

The true hardcore purists have gutted C-551 cans and installed replacements 
inside.  This requires a torch, patience, and a liking for the smell of 
burning carcinogenic PCB-laden oil.

This would be a good time to also install the Dallas Lankford 2-diode AGC 
mod.  This simple and easily reversible modification makes a night-and-day 
difference for reception of SSB signals.  Most of the improvement comes from 
installing just the diodes; it works very well without the rest of the 
procedure.  Check out r-390a.net , click on References, Pearls of Wisdom, 
SSB Conversion.

Drew

>
>Message: 3
>Date: Sun, 22 Dec 2002 09:28:17 -0500
>To: [email protected]
>From: MURPH <[email protected]>
>Subject: [R-390] C-551
>
>
>GM
>
>         Has anyone
>found a replacement for C-551 - the oil filled AGC cap?
>
>Thanks for your time
>
>Richard
>
>
>

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