[GreenKeys] GreenKeys Digest, Vol 99, Issue 39

[John Nagle]

On 4/24/2012 11:09 AM, greenkeys-request at mailman.qth.net wrote:
> Message: 3
> Date: Tue, 24 Apr 2012 13:05:24 -0500
> From: DR HOUSE<k9tty at dls.net>
> Subject: Re: [GreenKeys] Western Union Rectifier 69-B
> To: David Burns<dvdbrns at rcn.com>
> Cc:greenkeys at mailman.qth.net,vibroplex at mindspring.com
> Message-ID:<641210F2-F600-4DF9-A99B-E0BED42DC1B2 at dls.net>
> Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes
>
> Not sure where the "base down" comes from. The 83 in the TV-7D/U tube
> tester is horizontal.
> However the operation of a tube tester is not continuous.
>
> ??
> Don
> K9TTY

    Data sheets for early 82 tubes from the Cunningham Tube Company
do suggest a "base down" mounting.  But this is in the context of
"only a socket making very good filament contact and capable of
carrying 3 amperes continuously should be used".  Bear in mind
that early electronic connectors were very unreliable.

http://www.datasheetking.com/indexdl/Scans-008/Scans-00177151.pdf

    The RCA data sheet for the 83 tube does not call for base-down
mounting.

http://www.ronnierice.com/ebay/83%20RCA%20Tube/rca_83.pdf

    The "high end audio" guys suggest a 1-hour warmup on the filament,
in the base-down position, before applying high voltage for the first
time.

    If you can't find an 83, you can substitute a 5U4GB, which has
better specs, the same filament voltage and current, and no mercury.

http://www.hifitubes.nl/weblog/wp-content/rca-5u4gb.pdf

That was the standard power rectifier of the tube era, and
can rectify 1A at up to 1500V.  You can still get new 5U4GB tubes.
You'll have to replace the 4-pin socket with an octal socket,
and change the pinout.

Then you can get a solid-state 5U4 plug-compatible replacement.

http://tubedepot.com/ssr.html

All this is an overly complex way to get 120VDC at 60mA.

				John Nagle