[Test-Equipment] TV-7 Calibration

[k4pf at juno.com]

Hi,

I recommend that you check out Nolan Lee's web page on the military
tube testers:  http://www.webdsi.com/nlee/
His data sheets are more up to date than the military's, as well.
An amazing amount of work!

He points out the necessity of using a d.c. voltmeter
of the correct 1000 Ohm/Volt loading (or adding the proper
resistance across the input of a modern Hi Z instrument),
to duplicate the test equipment used in the military
test procedure.  This is important because the bias pot/screen supply
circuit is at high impedance, and the manual took into account
that they were using a 1000 Ohm/volt meter to do the measuring.

The military meter has a 50V scale and a 10V scale, so you will
need a 50K resistor across your probes to check values between 10V
and 50V, and a 10K resistor across the probes when measuring
below 10V. 

73,
Ed Knobloch


-- "DW Holtman" <tubestuff at comcast.net> wrote:
Hello,

I'm getting ready to go through a TV-7/U, step by step using the Depot manual (TM-11-6625-274-35). The first step, the bias voltage test calls out a test setup then asks for a reading of 3.0 +_.1 Volts. I'm reading 5.26 Volts.

My question is this. The procedure calls for using a TS-352 Multimeter. The only meters I have are high input impedance DVM and a VTVM. I know that a TS-352 will load the circuit and cause a lower reading. Is there anyway to make the necessary adjustments using a DVM or a VTVM?  <snip>