[R-390] R390A Audio Meter FS

[David Wise]

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
>
>On 9/21/2010 1:48 PM, ka9egw at britewerkz.com wrote:
>> What he said.  I always thought the audio meter had a 
>--->|---\/\/\/--- in
>> it.
>>
>> -----Original Message-----
>> From: r-390-bounces at mailman.qth.net
>> [mailto:r-390-bounces at mailman.qth.net]On Behalf Of David Wise
>> Sent: Tuesday, September 21, 2010 12:40 PM
>> To: r-390 at mailman.qth.net
>> Subject: Re: [R-390] R390A Audio Meter FS
>>
>>
>> Who'd have thought!  That opens up some possiblities.
>>
>> So I take it you took apart an audio meter
>> to get past the rectifier and maybe a resistor?
>>
>> Dave Wise
>> SWL in Hillsboro Oregon
>