[R-390] R-388 caps (OT)

[Roy Morgan]

On Jul 28, 2008, at 8:57 PM, 2002tii wrote:

> Roy wrote:
>
>> Of concern are any silver mica caps you may find.  They are suspect
>> now.  Get new replacements from Justradios.com in canada....
>
> One caution I would offer -- these folks offer "orange dip"  
> capacitors and say they are "dipped in orange epoxy like Sprague  
> Orangedrops used to be."  ... I would use nothing but Vishay/Sprague  
> 715P or 716P metal foil and polypropylene caps it tube radios where  
> film capacitors are indicated.

Don and others,

Modern caps are far and away more reliable in general than the old  
ones were even when new.

> until we have 40 years of experience indicating they are as reliable  
> as the Spragues, I'll use the real Orange Drops


The modest cost increase for true "Orange Drops" is not a big thing  
compared to the time and effort to get then IN there!  (I look forward  
to doing a couple of SP-600's that I own.)

> ... I never use film capacitors as bypass caps -- ceramics are much  
> superior in that role, ...  the best part for the job when I'm  
> putting in the effort to replace 50+ capacitors in devilish  
> locations in a radio.

Indeed.  I overhauled an SX-88 not long ago.. the thing may be worth  
$5,000 or more now that it is running well!  And talk about devilish  
locations!!!  I did use disk ceramics for bypass functions.  The  
original caps in the front end working from BC band to 120 mc were  
tubular papers with braid leads on them - special order no doubt.

Note: My security advisors tell me to state that the SX-88 is NOT  
mine,and has gone back to its owner.  (They threatened to charge me  
stiffly to increase the chain link fence to 10 feet, and for putting  
on more dogs for the night patrol.)

Roy




Roy Morgan
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