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Hickok  TV-7D/U Tube tester, Extremely nice condition, Depot overhauled / Cal\'d
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Hickok TV-7D/U Tube tester, Extremely nice condition, Depot overhauled / Cal\'d
Price: US $1250.00
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Here\'s a really nice TV-7D tube tester in excellent operating condition and cosmetic condition. It appears to me that it was never used in the field. There\'s no obvious wear either on the inside or outside of the case. This comes with the US Army Depot box when it was calibrated or overhauled in 1978.
I just checked the calibration (to Mil TM-11-6625-274-35) and it needed just one minor adjustment
since the overhaul. See my calibration test sheets in the last two pictures.
This has the standard accessories, and an unused tube chart. All of this looks unused.
As you can see from the pictures the front panel, and the chassis are also like new. The tube sockets are
likewise look unused.

Some info.
The TV-7D has several improvements over earlier units e.g. it has parasitic oscillation damping (ferrite
beads) and it has a higher GM range (position F) for testing the later (high Gm) tubes. This of course
will test all early tubes including Western Electrics. There are sockets for 4,5,6,7,8 octal. 8 loctal, 7
/ 9 pin minatures and acorns. It is possible to make adapters for the later 9/ 12 pin sweep tubes.
This has been completely calibrated to the Army Tech manual (TM 11-6625-274-35) specs. The two factors
that have the most influence on unit to unit repeatability are the signal voltage levels (step 4) and the
transconductane (plate AC current). These are right on their center values (see test calibration data).

The TV-7\'s are considered to be standard by many people. They\'re obviously built to the highest standard
and they don\'t have the "English" pot that many Hickok\'s used to change the transconductance range.
TV-7\'s that are calibrated properly don\'t depend on using a "standard" (6L6) tube for adjusting the
(transconductance) scales. Instead this calibration is done by using by using a known AC plate current
(from an isolated transformer) and knowing the AC grid test signal. Calibrated TV-7\'s are therefore very
repeatable from unit to unit.
Also, the TV-7D has a low range grid test signal (0.5VAC) whick makes it is especially useful for
accuratedly testing hi mu tubes like 12AX7\'s. Many TT\'s use 5 volts on the grid which will cause a hi mu
tube to saturated over part of the AC test cycle.
BTW these do a good job of checking many lower power transmitting tubes like 6146\'s 811\'s 572B\'s etc.
Many TT\'s will give good readings on weak tubes. Dropping the heater voltage one notch will accurately
weed out tubes with marginal emission.
All of the military manuals (operating, tube charts and three levels of repair) are on the BAMA web site.

This is by far the nicest TV-7D that I\'ve seen (I\'ve had dozens over the years).


Note that a few of the pictures have what appears to be a dark smudge in the lower left. This is a defect in my camera lens (time for a new one).


Shipping will be by UPS for 26 pounds from 91784. I can ship by Priority Mail to HI and AK.
No charge for good packing. I accept Paypal. Please make sure that your PP address is correct. Note that
Paypal requires a delivery signature.

California residents must add 8% sales tax.

Thanks & 73





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