[AMRadio] Valiant Tank Caps

Wed Feb 22 19:33:43 EST 2012

Good day, Thanks so much for the leads, I found some 3.5KV RF caps on Ebay. These are Russian Military guys but surely should not smoke like the 1.5KV snubber and silver mica ones did. I know what the owners manual from Johnson says but the caps on the market today do not seem to handle large amounts of RF very well. Then maybe the ones I got were defective. Let you know in several weeks after caps come over the big pond.
73's
Larry K9LWI

--- On Wed, 2/22/12, amradio-request at mailman.qth.net <amradio-request at mailman.qth.net> wrote:

From: amradio-request at mailman.qth.net <amradio-request at mailman.qth.net>
Subject: AMRadio Digest, Vol 97, Issue 28
To: amradio at mailman.qth.net
Date: Wednesday, February 22, 2012, 11:03 AM

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Today's Topics:

   1. Re: Valiant PI net caps (James R. La Frieda)
   2. Re: 15 AM Open Right Now (Don Cunningham)
   3. Re: Valiant PI net caps (ne1s at securespeed.us)
   4. Re: Valiant PI net caps (JohnPerz at aol.com)

----------------------------------------------------------------------

Message: 1
Date: Tue, 21 Feb 2012 09:20:54 -0800
From: "James R. La Frieda" <lafrieda at earthlink.net>
Subject: Re: [AMRadio] Valiant PI net caps
To: Discussion of AM Radio in the Amateur Service
    <amradio at mailman.qth.net>
Message-ID: <4F43D276.20205 at earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Hi Larry,

Have a Valiant, and although I haven't replaced the tank caps, I looked 
at the Valiant schematic and noticed that the tank caps are C 38 A, B, 
C, D at *150 mmf 500 V 5% silver mica*, and that the C39A, B, C and D 
are *350 mmf , 500 V  5% silver mica capacitors.*

If you go to justradios.com and look at their on-line Excel Order Form, 
you will note that they sell Silver mica capacitors at 500 V, 1000 V, 
1600 V and 6000V.

150 pf at 500 V  are .79 each

350 pf at 500 V are  .99 each

All the Best,
Jim ( N6MV)

On 2/21/2012 8:36 AM, Lawrence Steeno wrote:
> Good day, I have 2 Valiant transmitters on my bench now with leaky tank caps, especially the 300 mmf one. The octagon one with 3 caps in it are some what okay but suspect. There is another Valiant that is waiting for some also. Now I am wondering where I may get some of these for replacement. I tried RF Parts with no luck. I tried regular ceramic caps and they failed soon so I tried snubber caps at 2KV and they failed also. Where may I look and for what?
> I am lost and these transmitters are great units and should be warming up the ionosphere rather than holding down the top of my bench.
> Thanks a bunch.
> Larry K9LWI
>
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------------------------------

Message: 2
Date: Tue, 21 Feb 2012 12:38:28 -0600
From: "Don Cunningham" <donc at martineer.net>
Subject: Re: [AMRadio] 15 AM Open Right Now
To: "Discussion of AM Radio in the Amateur Service"
    <amradio at mailman.qth.net>
Message-ID: <2D4433D6A0E94C0385A0FE716A0EAC5A at DON>
Content-Type: text/plain; format=flowed; charset="iso-8859-1";
    reply-type=original

Sorry I missed you, Todd.  I was hearing W1GUD, I believe it was, in Florida 
so we could likely have worked!!  I plan to get on there more often.  I just 
forget 15M for some reason, and that's ALL I worked as a Novice, hi.  Worked 
all states except Mississippi.  Just couldn't find a station there on 15M!!
73,
Don, WB5HAK 

------------------------------

Message: 3
Date: Tue, 21 Feb 2012 16:58:03 -0500 (EST)
From: ne1s at securespeed.us
Subject: Re: [AMRadio] Valiant PI net caps
To: "Discussion of AM Radio in the Amateur Service"
    <amradio at mailman.qth.net>
Message-ID:
    <50273.216.220.248.166.1329861483.squirrel at webmail.midmaine.com>
Content-Type: text/plain;charset=iso-8859-1

> Good day, I have 2 Valiant transmitters on my bench now with leaky tank
> caps, especially the 300 mmf one. The octagon one with 3 caps in it are
> some what okay but suspect. There is another Valiant that is waiting for
> some also. Now I am wondering where I may get some of these for
> replacement. I tried RF Parts with no luck. I tried regular ceramic caps
> and they failed soon so I tried snubber caps at 2KV and they failed also.
> Where may I look and for what?

I used 4 snubber caps (the large silver micas) in series-parallel to
replace each of the postage-stamp micas used as padders for 160M and 80M
(IIRC) on the high-impedance side of the pi-net output in a friend's
(KB1IAW) Valiant. In addition to the RF voltage across them, there is
significant RF current flowing in these caps, so paralleling them helps
out there.

That transmitter has seen a lot of use on those bands since I did that
work at least five years ago, and there has not been a failure.

73/GL,
-Larry/NE1S

------------------------------

Message: 4
Date: Tue, 21 Feb 2012 17:01:54 -0500 (EST)
From: JohnPerz at aol.com
Subject: Re: [AMRadio] Valiant PI net caps
To: amradio at mailman.qth.net
Message-ID: <1a423.763a1aa.3c756e52 at aol.com>
Content-Type: text/plain; charset="US-ASCII"

I was not able to keep the smoke in the 500 volt caps.Got 1500  volt ones, 
so far, holding up. Not sure if this indicates another problem, There  was a 
discussion about this on the AM radio forum..........de  WA2FNS

In a message dated 2/21/2012 12:21:16 P.M. Eastern Standard Time,  
lafrieda at earthlink.net writes:

Hi  Larry,

Have a Valiant, and although I haven't replaced the tank caps, I  looked 
at the Valiant schematic and noticed that the tank caps are C 38 A,  B, 
C, D at *150 mmf 500 V 5% silver mica*, and that the C39A, B, C and D  
are *350 mmf , 500 V  5% silver mica capacitors.*

If you go to  justradios.com and look at their on-line Excel Order Form, 
you will note  that they sell Silver mica capacitors at 500 V, 1000 V, 
1600 V and  6000V.

150 pf at 500 V  are .79 each

350 pf at 500 V  are  .99 each

All the Best,
Jim ( N6MV)

On  2/21/2012 8:36 AM, Lawrence Steeno wrote:
> Good day, I have 2 Valiant  transmitters on my bench now with leaky tank 
caps, especially the 300 mmf one.  The octagon one with 3 caps in it are 
some what okay but suspect. There is  another Valiant that is waiting for some 
also. Now I am wondering where I may  get some of these for replacement. I 
tried RF Parts with no luck. I tried  regular ceramic caps and they failed 
soon so I tried snubber caps at 2KV and  they failed also. Where may I look 
and for what?
> I am lost and these  transmitters are great units and should be warming 
up the ionosphere rather  than holding down the top of my bench.
> Thanks a bunch.
> Larry  K9LWI
>
>  ______________________________________________________________
> Our  Main Website: http://www.amfone.net
> AMRadio mailing list
>  Searchable Archives:  
http://www.mail-archive.com/[email protected]/
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>
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>

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End of AMRadio Digest, Vol 97, Issue 28
***************************************