[GreenKeys] Western Union Rectifier 69-B

[Richard Knoppow]

----- Original Message ----- 
From: "DR HOUSE" <k9tty at dls.net>
To: "David Burns" <dvdbrns at rcn.com>
Cc: <greenkeys at mailman.qth.net>; <vibroplex at mindspring.com>
Sent: Tuesday, April 24, 2012 11:05 AM
Subject: Re: [GreenKeys] Western Union Rectifier 69-B


> 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
    Its given in the RCA Receiving Tube Handbooks.  My 
oldest is RC-14, from 1940, which has complete details on 
the 83 but the same advice is carried over into much later 
handbooks.  The advice is general for mercury vapor tubes 
and is also give for the 866/866A and 872/872A in the RCA 
Transmitting Tube handbooks.
    Where tubes have been in storage for a lengthy period, 
especially if they have not been stored vertically, its a 
good idea to sit them vertically for a day or so to allow 
the mercury to pool in the bottom of the tube. Then apply 
filament voltage only for a time, at least fifteen minutes 
and allow the tube to sit and cool again to pool the 
mercury. This makes sure no mercury has stuck to the 
elements.  After this the larger tubes should be operated 
for about five minutes with filament only before applying 
plate voltage.  The 83 was designed for use in receivers and 
other small equipment and may not need such a long warm up 
but I would give one at least two minutes of filament 
voltage before applying HV.
     There was a vacuum tube replacement for the 83 called 
an 83V, a dual diode with an indirectly heated cathode to 
reduce the voltage drop.  Its still not as low as the 
mercury vapor tubes but is enough to be satisfactory in many 
circuits. Especially when used in receivers the 83 tended to 
produce a lot of electrical noise or "hash" which was 
difficult to eliminate, the vacuum tube rectifier does not 
suffer from this so was more satisfactory when used in 
receivers and probably audio equipment. These tubes were 
supplanted by vacuum tube rectifiers, selenium rectifiers in 
some applications, and, of course, eventually silicon 
diodes.
    BTW, the RCA book states that darkening of the envelope 
is normal and does not affect the performance.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com