[ARC5] Use of a Variac

[J Mcvey]

 The ones I'm thinking about are usually bolted to the chassis , not the tab type. Very old 

    On Thursday, April 23, 2020, 8:42:01 PM EDT, Richard Knoppow <1oldlens1 at ix.netcom.com> wrote:  
 
     Oil filled electrolytics are new to me. Are you sure this was 
not a paper cap? There are both wet and dry electrolytics. The 
very early ones were wet, that is, they had liquid electrolyte. 
They were position sensitive. Then so called dry electrolytics 
were developed. In these the electrolyte is a paste.
    The oil filled caps I know about are paper or sometimes 
plastic dielectric. The oil is used as both a sealant against 
moisture and sometimes to increase the dielectric constant. I 
have seen plenty of WW-2 vintage bathtub oil filled paper caps 
where the seals disintegrated letting the oil out. A mess.
    I may be wrong but I think electrolytic caps need to be 
ventilated, which oil filling would make impossible.

On 4/23/2020 4:42 PM, J Mcvey via ARC5 wrote:
>
> The only ancient electrolytic caps that I ever ventured to save 
> is the oil type. Sometimes the seal can be repaired and 
> refilled..  The dry type just get changed.
>
> When bringing up a radio in unknown condition, I check for 
> obvious short issues with a DMM before applying power.
> I use a 60 watt incandescent light bulb in  series with the 
> line. This does a pretty good job of current limiting and is a 
> visual indicator of the current being drawn. After the initial 
> current drawn by the caps charging, the bulb should be dim. If 
> the bulb stays bright , there are issues. if the bulb is bright 
> at moment the switch flipped on , in a tube set, the 
> transformer may be bad or has a short in or across a winding.
>
> I don't have the patience to try reforming caps that may or may 
> not respond to treatment.
> On Thursday, April 23, 2020, 7:25:40 PM EDT, Mike Feher 
> <n4fs at eozinc.com> wrote:
>

-- 
Richard Knoppow
1oldlens1 at ix.netcom.com
WB6KBL

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