[Test-Equipment] AN/PRM-10 Question

[Al Parker]

Hi Richard,
	I have a PRM-10, that I haven't used for 6-8-10 yrs.  I could pull it 
out, open it up, & ck anything (later tonite) if you run out of things 
to do.
73,
Al, W8UT
www.boatanchors.org
www.hammarlund.info

"There is nothing -- absolutely nothing -- half so much
worth doing as simply messing about in boats"
Ratty, to Mole

On 10/30/2011 4:37 PM, Richard Knoppow wrote:
>
> ----- Original Message -----
> From: "Brooke Clarke"<brooke at pacific.net>
> To: "Richard Knoppow"<1oldlens1 at ix.netcom.com>; "Discussion
> of Electronic Test Equipment"
> <test-equipment at mailman.qth.net>
> Sent: Sunday, October 30, 2011 1:25 PM
> Subject: Re: [Test-Equipment] AN/PRM-10 Question
>
>
>> Hi Richard:
>>
>> Is it possible that there's a short somewhere else that's
>> in parallel with the choke?
>> Did you check with the tube unplugged?
>> If you have a digital camera try taking some close up
>> photos of the area from different angles an look at them
>> on your computer monitor, i.e. use the camera as a
>> microscope.
>>
>> Have Fun,
>>
>> Brooke Clarke
>> http://www.PRC68.com
>> http://www.End2PartyGovernment.com/
>>
>>
>       Thanks for the very quick response.
>       This little choke is connected between the ground side
> of the filament and the cathode of the 955 oscillator.
> Physically it goes between the filament clip of the base and
> a collett type connector for the cathode pin so it can be
> pulled off and measured directly. When connected the tube
> acts like its running with no bias because the B+ gets
> pulled way down. If I lift the choke the plate voltage goes
> way up. To me that indicates the tube is either drawing no
> plate current or too much plate current. I will try a 47 ohm
> resistor in place of the choke to see what happens as  a
> trouble shooting tool (not sure I have a resistor of the
> right value).
>       I've done a visual inspection of the choke using a
> strong LED flashlight and magnifying glass but can not find
> the fault. Its possible its not a single layer, I will
> inspect again. I can't understand how falling a couple of
> feet onto a thick carpet could have damaged something that
> can't move but who knows. The unit was intermittant when I
> got it.
>       I would really like to either obtain a replacement
> choke or at least to know what its inductance is supposed to
> be so I can make one if necessary.
>
> --
> Richard Knoppow
> Los Angeles
> WB6KBL
> dickburk at ix.netcom.com
>
>
>
>
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