For the 0A2 replacement...might want to check this out..
http://www.solidstatetubes.com/0a2-and-0b2.html
Thanks..Rich N7TR
Rich N7TR
ex KI3V, N3AMK, WB3JOV
www.n7tr.com<http://www.n7tr.com>
http://www.qrz.com/db/N7TR
Telnet: dxc.n7tr.com N7TR DXCluster
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Charlie
Cunningham
Sent: Friday, December 20, 2013 9:21 PM
To: 'Bill Cromwell'
Cc: 'top Band'
Subject: Re: Topband: DX-100 adventure - progress
Hi, Bill!
That's great! You're good to go with the elecrolytics, then!
BTW - as for the chirp on the signal - the DX-100 VFO and voltage regulator
was pretty much what they sold separately as the VF-1 vfo. The DX-40 had a
socket to power it, but I never could get rid of the chirp, until I built a
separate PS for the VFO. The OA2 gas tube just wasn't stiff enough to eliminate
the chirp. You might be able to eliminate most of the chirp by replacing the
gas tube with a Zener Diode. By the time you get up ro a 100 volts with the
Zener, it's really avalanche breakdown and has a pretty stiff knee. Might
improve your chirp!
Have Fun!
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Bill Cromwell
Sent: Friday, December 20, 2013 11:12 PM
To: Charlie Cunningham
Cc: 'top Band'
Subject: Re: Topband: DX-100 adventure - progress
On 12/20/2013 11:00 PM, Charlie Cunningham wrote:
> BTW, Biii - tip/suggestion - for those series-connected electrolytics
> you probably should put a pair of equal value resistors - one across
> each
series
> capacitor, as the leakage currents will not be equal in each capacitor
> in each series string and the DC voltage won't divide equally across
> each capacitor unless you put individual "bleeder" or "swamping"
> resistors
across
> each cap in the series pair to equalize the DC across each capacitor
> in
the
> series! I'll be interested to see how it turns out! I never had a
> DX-100 "Benton Harbor Kilowatt"! I did have a DX-40 for a while, but
> no 160 on that one, though! I do have an EF Johnson Navigator in
> pretty good
condition
> that needs to have all of its electrolytics replaced because of their
age.
> I does have 160 (and 11 meters also!).
>
> Good luck and Merry Christmas!
>
> 73,
> Charlie, K4OTV
>
>
Hi Charlie,
In the DX-100 there is already a big honking pair of bleeder resistors so that
the bleeder is divided with one half across each half of the series pair. I
think that's what you meant. The DX-100 originally had two caps rated at 450
volts in series and the bleeder set up that way.
73,
Bill KU8H
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