[Test-Equipment] TV-7 Calibration

[Eric Lemmon]

I beg to differ; the bias voltage is DC, not AC.  But, I am curious- why did
you think it was AC?

I have the Army TM 11-6625-366-10 for the TS-352 meter, and it shows that
the meter has both 1,000 ohms/volt and 20,000 ohms/volt ranges for DC.

I have a TV-7A/U tube tester, and I have all of the Army TMs that cover it.
Please take careful note that the testing procedure and the expected
voltages vary among the various TV-7 models.  Also, be aware that the
calibration procedure must be performed in a specified sequence; you cannot
just jump to the bias adjustment without completing some prior steps.  Be
careful that you perform all of the preoperational switch and control
settings before taking any readings.

The total resistance across the screen and bias power supply is a little
over 4,000 ohms, which is not particularly high impedance.  It was pretty
standard practice to use the 20,000 ohms/volt setting, which is what a
Simpson 260 or an Air Force PSM-6A meter provides.  Figure 38 on page 48
shows the meter settings for voltage measurements.

73, Eric Lemmon WB6FLY
 

-----Original Message-----
From: test-equipment-bounces at mailman.qth.net
[mailto:test-equipment-bounces at mailman.qth.net] On Behalf Of DW Holtman
Sent: Thursday, October 11, 2007 9:47 AM
To: Discussion of Electronic Test Equipment
Subject: Re: [Test-Equipment] TV-7 Calibration

Robert,

Great information. I should have specified, the voltage in question is AC 
volts, not DC Volts. Any idea if what the imput inpedance might be for a 
TS-352 type of VOM in the AC ranges?

Thank you,
DW Holtman