[Johnson] Need help with a Valiant…

[Dutch Maurer WB7DYW]

Ron,
I replaced the disk ceramic caps with silver mica's and still no joy, I can peak the exciter but the final cap has no effect (no dip), if I turn up the drive I can peg the plate meter and get about 15 watts out, there is no change when adjusting the coupling "AUX & FINE"...
 
I have checked all the voltages and they all seem within specs except the bias, according to the manual it should be -85 but I only get -80 and when I turn on the B+ it drops to about -75, checked the tubes on a Hickok TV7/DU tube tester and did not find any weak or shorted tubes, any ideas or is there a Valiant guru I could ask about this problem???
 
I love this old radio and would like to get back on AM but this has me chasing my tail, Valiants are not my strong suite *&^%$#@!

73's Dutch WB7DYW
CCA Member #918
Please visit my website: www.wb7dyw.com

Success is not a place in time, it is an attitude…

--- On Sun, 8/7/11, Ronald Erickson <ronalderickson777 at gmail.com> wrote:


From: Ronald Erickson <ronalderickson777 at gmail.com>
Subject: Re: [Johnson] Need help with a Valiant…
To: "Dutch Maurer WB7DYW" <wb7dyw at yahoo.com>
Date: Sunday, August 7, 2011, 1:06 PM


I am guessing but I think it has something to do with your bias being off.  It might be you have tube problems so they should be checked in case something has shorted.  I have a couple of Valiants but I have not experienced that problem yet.  I would put clipping diodes across your meter if it would be me so you do not ruin that.  I have clipping diodes across my meter for years.  I also use 3B28s for rectification which might be a problem too if you have not done that. 


73,


Ron, K0IC



On Sun, Aug 7, 2011 at 12:53 PM, Dutch Maurer WB7DYW <wb7dyw at yahoo.com> wrote:

My Valiant suddenly stopped putting out RF on 75 meters, I switched to 40 and it loaded a little, about 90 watts then that also quit, I am thinking it is the loading star cap, I know they are a weak point on the Valiant, I replaced them with disk ceramic caps but still no output if I turn up the drive the plate meter will peg to the right so I am thinking the loading caps are not up to the load, any suggestions on what is the problem and if its is the loading caps what should I use and is there a source for them, any suggestions are welcome…

73's Dutch WB7DYW
CCA Member #918
Please visit my website: www.wb7dyw.com

Success is not a place in time, it is an attitude…
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Ronald D. Erickson, K0IC 
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