[R-390] R390A Audio Meter FS

[rbethman]

  I suggest you go look at TB-102.

Note the CR-xxx that is mounted there.

I wasn't aware that anyone needed to "prove" what is in the circuit or 
the manual.

I simply restore these for MY purposes.  One '67 EAC and a Collins '51 
contract from St. J's.

Members of the list have a tendency to focus in on "small" areas, NOT 
open their minds and eyes to the WHOLE!

Bob - N0DGN

On 9/21/2010 3:00 PM, David Wise wrote:
> Not yet.  The only place it's marked with a polarity is on the
> Mainframe Wiring pictorial diagram, and that's nonsense,
> because M101 is fed with audio AC.  That puts at least a
> rectifier inside, so although you can determine the FS
> current externally, to measure the resistance you have
> to bust it open.  It could be a 17-ohm movement, but
> you haven't proven it.  I hope it is...
>
> Dave Wise
> SWL in Hillsboro Oregon
>
>> -----Original Message-----
>> From: r-390-bounces at mailman.qth.net
>> [mailto:r-390-bounces at mailman.qth.net] On Behalf Of rbethman
>> Sent: Tuesday, September 21, 2010 11:15 AM
>> To: r-390 at mailman.qth.net
>> Subject: Re: [R-390] R390A Audio Meter FS
>>
>>   Please pull out the TM 11-856A.
>>
>> As you go through the schematics, you'll note the BOTH meters have a +
>> and a - connection.
>>
>> Keep digging and reading.....
>>
>> These are the SAME interior devices with different faces.
>>
>> Bob - N0DGN