[Hammarlund] Oil-Filled Caps (BC-779)

[Les Locklear]

Just a KISS answer on the oil filled caps on the SP-200 (and variants) power 
supply.

I've "NEVER" seen a bad one yet. Nor, have I seen any "leakers." I think RCA 
had the patent on the leaking oil filled caps.

As usual, ymmv, taxes extra.

Les Locklear
Professional Curmudgeon
Equal Opportunity Annoyer

----- Original Message ----- 
From: "Al Parker" <anchor at ec.rr.com>
To: "Carole White-Connor" <carolew at bellatlantic.net>; "Hammarlundqth" 
<hammarlund at mailman.qth.net>
Cc: <milsurplus at mailman.qth.net>
Sent: Saturday, January 20, 2007 1:53 PM
Subject: Re: [Hammarlund] Oil-Filled Caps (BC-779)


> Hi Joe,
>    I meant to get back to you after your post on your "final report" on
> the BC-779, but somehow things got away.  May I use that info as an
> addition to my webpage?  It should be of help to follks.  Will give you
> credit, of course.
>    On the oil-filled caps, as long as they're not leaking, they should
> last 'forever'.  You can do a very rough ck with an ohmeter, the meter
> will go immediately toward zero ohms, then should build up fairly quickly
> to over a megohm, and keep on going.  That'll show it's got capacitance,
> only doing a comparison to a known value will give you a rough
> quantitative measure of how much.  An ESR meter is the best to determine
> the quality of a capacitor (Equivalent Series Resistance).  There is some
> way to simulate it, but I don't remember just what.  I think the EXR mtr
> uses a pulse at 1kc or more, and reads out in ohms, from milli-ohms to 10
> or above, the lower the better.  Or do as was suggested, just measure the
> ripple you get.
>    600v is a bit over an overkill, but probably an easily reached  no.
> for oil filleds.  If you replace with electrolytics, use something at
> least 10% over the actual voltage.  450v for the HV, lower for the others,
> but if one of the bleeder/divider resistors fails, you might get full HV
> on the LV section, I don't remember exactly the setup.
> 73,
> Al, W8UT
> New Bern, NC
> BoatAnchors appreciated here
> http://www.boatanchors.org
> http://www.hammarlund.info
>
> ----- Original Message ----- 
> From: "Carole White-Connor" <carolew at bellatlantic.net>
> Cc: <hammarlund at mailman.qth.net>; <milsurplus at mailman.qth.net>
> Sent: Saturday, January 20, 2007 10:34 AM
> Subject: [Hammarlund] Oil-Filled Caps (BC-779)
>
>
>>     I'm working on a power supply for a BC-779. It has the original
>> oil-filled filter caps. I have yet to fire it up. However, I intend to
>> use this BC-779 and power supply on a regular basis for SWLing. The
>> receiver is a great-performing set.
>>
>>     Here are my questions:
>>
>>     1. I understand that these oil-filled caps are more reliable than
>> electrolytics of the same vintage. However, what is the consensus on
>> whether they should routintely be replaced?
>>
>>     2. How can I test them? I do not have a cap checker. I will have to
>> use a VTVM.
>>
>>     3. These caps are rated at 600 WVDC. Is that overkill? What would be
>> the recommendation for the voltage rating of replacement caps?
>>
>>     As always, thank you for your help and guidance.
>>
>>                             Joe Connor
>>
>
>
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