[Milsurplus] Rectifier Module, ahoy!

[Christian Fandt]

Dennis,

I have a manual set for the SCR-268-B. It also covers the 268-C.

Firstly, the xmtr for the 268-B set is designated BC-407-A, no reference in 
the manuals to a -677. Those other references to which you attribute the 
-677 are probably incorrect if they specify the SCR-268-A or -B or -C.

Secondly, the ring oscillator in the -407-A uses 16 of the Eimac 100 TS 
triodes, not GL-434A.

Thirdly, it must be pointed out that this manual set is dated July 1, 1943 
(the manual describing the -C is dated Aug. 1, 1943). As later production 
of the 268-* was carried out, very possibly the GL-434A was substituted. 
Others here with actual hardware (??) or later manual dates should be able 
to confirm this.

Fourthly, to explain the 268-C, it is simply a version of the -B shipped 
with less "stuff". What I mean is that the -B consisted of a trailer mount 
(holding the antennae, operator's controls, viewing devices, modulator, 
xmtr, etc.), four trucks and all of the test equipment, maintenance tools, 
etc. while the -C just has the trailer mount (with a similar compliment of 
aforementioned gear) and only one trailer van. Maint eqpt and spares were 
provided to cover three 268-C's on a platoon basis.

There was a heap o' stuff needed to support one 268-B unit thus requiring 
four trucks, one 6 1/2 ton and three 2 1/2 tonners. A decidedly big target 
from the air.

The RA-38 rectifier is certainly a big honker and the 25kva 4-cyl generator 
is not a tiny thing either! Both these units plus spares and cables were 
shoehorned into a K-34-D trailer for the 268-C.

Hope this helps a bit with regard to your GL-434A info search and 
associated 268-* equipment versions.

Regards,.  Chris

NNNN

Upon the date 07:30 PM 2/9/04 -0500, W7QHO@aol.com said something like:
>All,
>
>All the references to the SCR-268 in this thread caught my eye.   I'm looking
>for information on the
>GL-434A, a medium sized WW2 era external anode triode.   "Tube Lore" shows it
>as being used in the BC-677 which other references list as a transmitter and
>part of the SCR-268A.   Don't know if this tube was used in the modulator or
>in the transmitter ring oscillator.   The references I've been able to locate
>say that sixteen Eimac 100TS tubes were used in the osc. in the 268A but 
>maybe
>the GL-434A was used in later versions?   Does anyone know more?   Would be
>grateful if only to verify the filament voltage and current requirements.
>
>Dennis D. W7QHO
>Glendale, CA
>
>
>
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Christian Fandt,    Electronic/Electrical Historian
Jamestown, NY  USA      cfandt@netsync.net
         Member of Antique Wireless Association
         URL: http://www.antiquewireless.org/