[R-390] Cap Question

[Bob Camp]

Hi

As far as I can see there is no reason at all to *need* 400 volt caps 
on the filament circuit. There is also no real reason to worry about 
leakage on filament bypass caps. I would leave them in place unless 
they are obviously damaged.

	Take Care

		Bob Camp
		KB8TQ


On Mar 16, 2005, at 11:33 AM, Barry wrote:

> I should clarify.  My RF deck has the original brown beauties in it.  
> I just
> used the picture as reference to show which caps I was talking about.  
> I
> agree: these look like they are replacements.
>
> In my first RF deck rebuild, I replaced these with 400V Orange Drops, 
> but
> they were a real pain to position and I was wondering if ratings like 
> this
> are needed in this circuit.
>
> Thanks,
>
> Barry(III) - N4BUQ
>
> ----- Original Message -----
> From: "Cecil Acuff" <chacuff at cableone.net>
> To: "Barry" <n4buq at aol.com>; <R-390 at mailman.qth.net>
> Sent: Wednesday, March 16, 2005 9:42 AM
> Subject: Re: [R-390] Cap Question
>
>
>> Looks to me like they have already been replaced.  Someone may have 
>> just
>> used what was on hand.  Looking at the solder joints and the 
>> insulating
>> tubing it looks like recent (relative) work.  Maybe from a Mil. 
>> Overhaul.
>>
>> Cecil...
>>
>> ----- Original Message -----
>> From: "Barry" <n4buq at aol.com>
>> To: <R-390 at mailman.qth.net>
>> Sent: Wednesday, March 16, 2005 9:24 AM
>> Subject: [R-390] Cap Question
>>
>>
>>> Looking at the caps in my "new" R390A RF deck, I'm considering 
>>> replacing
>>> the
>>> three brown beauties in it.  I'm curious, though, about two of them.
> They
>>> are used in the heater thermostat circuit of the crystal oscillator 
>>> can.
>>> In
>>> the picture referenced below (thanks, Don), they are the big, yellow
> ones
>>> in
>>> the upper right corner:
>>>
>>> http://militaryradio.com/Images/390rfd.jpg
>>>
>>> The heater voltage is 6.3VAC and I'm wondering why the designers used
> 400V
>>> or better caps here.  Is this necessary because the noise spikes are
>>> considerably larger than 6.3V or is it possible that these were just
> handy
>>> since there were so many other 0.1mfd @ 400V caps used in other 
>>> places
> in
>>> the radio.
>>>
>>> Any comments?
>>>
>>> Thanks,
>>>
>>> Barry(III) - N4BUQ
>>>
>>> _____________________________________________________________
>>> R-390 mailing list
>>> Home: http://mailman.qth.net/mailman/listinfo/r-390
>>> Help: http://mailman.qth.net/faq.htm
>>> Post: mailto:R-390 at mailman.qth.net
>>> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>>>
>>
>>
>>
>
> _____________________________________________________________
> R-390 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-390
> Help: http://mailman.qth.net/faq.htm
> Post: mailto:R-390 at mailman.qth.net
> Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>