[R-1051] R-1051B/URR R-23?

[Francesco Ledda]

Jim,

R-23 is connected between E10 and E11 of 4VDC PWR and SPLY & Vernier Control
board; it is in parallel with R5 (64.9 ohm). On one side, there is the +20
and on the other side 4V. NAVSHIPS 0967-427-401 has the proper schematic.  

Frank
KF5RXV

-----Original Message-----
From: R-1051 [mailto:r-1051-bounces at mailman.qth.net] On Behalf Of David Wise
Sent: Thursday, July 09, 2015 5:42 PM
To: R-1051 Discussion Group
Subject: Re: [R-1051] R-1051B/URR R-23?

I can't find anything either.  I looked in scans of TO 31R2-2URR-221C (the
"B&C Tech Supplement") and Navships 0967-970-9010.  In the latter, the
revised chassis diagram is "Temporary Change 2 - To Be Supplied" on an
otherwise blank page.  Curse!

This is sheer guesswork, but perhaps the 100cps draws more +20 than the old
500cps did, and they added R23 to conduct some current around the pass
transistor to avoid heating it excessively.  In that case, I'd say the
dangling end of your resistor should go to the +25V rail.

Dave Wise

-----Original Message-----
From: R-1051 [mailto:r-1051-bounces at mailman.qth.net] On Behalf Of Jim Green
Sent: Thursday, July 09, 2015 3:11 PM
To: r-1051 at mailman.qth.net
Subject: [R-1051] R-1051B/URR R-23?

 I foolishly took the faceplate off my R-1051 so I could get it clean &
repaint it. After cleaning it I decided repainting was not required. It is
never going to be a new radio so I can live with a few blemishes on the
faceplate. Also, I checked into silkscreen costs and that was the deciding
factor.

I took lot's of notes and pictures & have it all back together as per the
schematic. Only one caveat. There is a large power resistor mounted on the
aluminum vertical support & shield plate that is is right behind the front
panel. R-23 is printed on the vertical support plate and the power resistor
is mounted with 2 each  4-40 screws to the plate. The resistor has a value
of 64.9 Ohms at 10 watts. One end of the resistor is connected to the 100CPS
control board at a point that says +20VDC from A2A6. My question is where
does the other end of this resistor connect? I cant find R-23 on any of the
schematics. Can anyone help?

I have the updated version of the service manual & I can find R23 on one of
the top photos. I just cannot find a R-23 o any of the schematics  with this
value.

Jim
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