[R-390] 6T4F

Tue, 23 Jul 2002 01:50:45 -0700

Hello George,
I did a FEDLOG Search of your MYSTERY 6T4F which should be identical
electrically to the 6T4,  NSN 5905-00-173-5998, which cost the tax payers
$2.33 when ? last procured by the U.S. NAVY.  By the way this could be
mistaken for the 6T4 Vacuum Tube 7-Pin miniature UHF Triode Oscillator. Your
6TF4 is a RESISTOR, CURRENT REGULATING, AC/DC, Current Range 0.58 to 0.64
Amperes, 4.3 Volt threshold, 7Pin miniature with T5-1/2 envelope and says
the application was"VL",whatever that implies. It could stand for Voltage
Limiter. Can you take an accurate DC Resistance measurement between pins 2 &
7  and let us know what the cold resistance is?

Here is some interesting info on the the 3TF7 Current Limiting Resistor as
specified for the R-390 Series. The FEDLOG description specifically
identifies this as Application = R-390/URR,  AC/DC, 0.040 to 0.260 Amperes,
10.2 Volts Threshold,  9-Pin Miniature with T-6-1/2 envelope. NSN
5905-00-259-1964, and was last procured $118.27. Measured DC Resistance is
approximately 12-12.75 Ohms.
Now, here is an interesting twist to the story.  Amperite PN: TJ311M01, NSN
5905-00-681-4707; DC, Current Range 0.31 to 0.33 Amperes, 8.0 Volts
Threshold,  9-Pin Miniature with T-6-1/2 envelope. The FEDLOG states "WHEN
EXHAUSTED USE 5905-00-259-1964" which is a 3TF7.  Hmmmmm! Makes you
wonder-What we really need here is to do a close scrutiny of the TM/TO's for
the R-389, R-390, R-390A. and R-391 Part List and see what part number and
stock number was listed.

I use an outdated FEDLOG (OCT 98)  since there is a lot of purging of older
parts and stock numbers. I still have the old micro-fiche but only the
MCRL-1 and MCR-II which does not have the descriptions. Also, I will trust
the facts of the manuals for the particular equipment before I fully endorse
the info as presented in the Federal Supply Systems. Errors have been made
such as requisitioning 1000 bolts for tower rehab and receiving 1000
anti-tank mines with the SAME NIIN which used to be FIIN. I WAS THERE!

Ifsome one has the parts manuals for the above equipment, perhaps they can
shed additional light on the subject.

STAY COOL!
73,
Glen Galati,  KA7BOJ, ex WB0AXK, DL4GG, HL9WA
Tacoma,  WA

----- Original Message -----
From: George Blahun Jr. <[email protected]>
To: <[email protected]>
Sent: Sunday, July 21, 2002 10:53 AM
Subject: [R-390] 6T4F

> Hello.  While cleaning the basement I found a cache of tubes, most of
which
> are for my 1955 Collins R-390A.  However, a bunch are Amperite 6T4F
ballast
> tubes.  Does anyone know what radio they are for?  Thanks.
>
> George
>
>
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