[Milsurplus] VR tube question

[mac]

Robert,

First thing to check with an unfamiliar T-195 with (apparently) no  
excitation is whether or not the MO output has been rerouted for RTTY  
use.  For a quick check put a jumper between the two BNC connectors on  
the front panel to the right of the power input socket and see if this  
fixes the problem.

You could, of course, also have a short circuit somewhere in the 150  
line from pin 5 on the 0A2 up to or inside the MO module (check  
C810).  For starters pull the 0A2 and measure the resistance between  
pin 5 on the socket and ground and see what you get.

Dennis D. W7QHO
Glendale, CA



On Sep 15, 2010, at 11:58 AM, Robert Goff wrote:

> Greetings to the list.  I'm hoping someone can help me-I'm a pretty
> inexperienced serviceman.
>
> I've been working this morning on a T-195 with (apparently) no MO
> output.  I've traced the problem back to the voltage regulator module
> next to the PTO.
>
> Checking at the MO plug I had no +150V regulated.  I checked the
> limiting resistor which is 3K-just like it's supposed to be. But, when
> I replaced the OA2 with 2 others I had, there was no change-still no
> 150V.
>
> When I pull the regulator tube I have 250 volts at pin 1, with the
> tubes in this drops to nothing.
>
> Is this just a case of three bad 0A2s?
>
> Help!
> Robert
> W7MKA
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