[R-1051] Update - Pretty Much Working

Tue Jul 31 20:18:03 EDT 2012

Dennis impressive and I have a very very healthy respect for the turret
assembly.
Great to see all that you have done.
As to the 5 mc oscillator reference. I just use an external ref to feed the
1051.
It comes from a very good Rb ref and I use GPS to evaluate the RBs
frequency. I have it so I used it.
Regards
Paul.

On Tue, Jul 31, 2012 at 7:03 PM, David Wise <David_Wise at phoenix.com> wrote:

> I found a procedure for removing the 1MC motor in
> NAVSHIPS 0967-034-2000 (Technical Manual for Repair of
> AN/WRC-1 and R-1051/URR 2N Modules), which I got from
> Al Parker's boatanchors site after discovering the
> link in the mail archive.  It's paragraph 3-5.
>
> I did not have to do all that to get the motor out.
> The only wires I had to unsolder were the motor wires
> themselves, and one coax.  Then it was possible to
> separate and flex and rotate just enough to free it.
> The brushes were okay.  I just cleaned the commutator,
> and added oil to the motor end bearings.  As caution
> overcame excitement, I decided not to open up the
> reduction gear assembly.  I got it all back together,
> and the 1MC was happy.  I still have to make sure it's
> putting out as clean and loud a signal as it's supposed
> to, but at least it doesn't sound scary anymore when
> the motor runs.
>
> I have run into various other troubles and fixed them.
> I'll list them in case someone else can benefit.
>
> - Hard to describe the symptoms, but I highly recommend
>   that you touch up the various trim-pots in the Spectrum
>   Generator, and, for 1051-plain, the 500cps Lock pot.
>   All of mine were at or over the edge, resulting in
>   ragged, intermittent, or off-frequency injection signals.
>
> - I traced an intermittent blank-out to loss of 10kHz spectrum
>   at the 1&10kc synth.  It turned out to be a bad SMB connector
>   on the board.
>   It looked like a lot of work to replace it, so I tried
>   rerouting the cable so the plug mated at a different
>   angle.  Seems okay for now.
>
> - My radio is a patchwork of various age modules.  One IF
>   looks original (NAVSHIPS 98481A or NAVELEX 0967-LP-970-9010),
>   with a 9-transistor A1 board, while the other has a
>   13-transistor A1 like the R-1051H (EE125-AF-OMI-010/E110-R1051H),
>   which would support MGC/FAST/SLOW if my front panel did.
>   (It might have been introduced in a lower model, but I
>   don't have any other manuals.)  Someone inadvertently
>   stuck an early shield can on it, so the silkscreened
>   board layout is wrong.  Does anyone have a spare late can?
>
>   Someone put the old IF's AGC Threshold trim-pot
>   at full-CCW like he started to adjust it.  I think I
>   got it straightened out, but the three procedures I
>   have available to me (four, if you count the
>   test-fixture-only one in R1051H) are pretty different
>   from one another.  Does anyone have a favorite?
>
>   My RF module doesn't match any manual I have.  Unlike
>   NAVSHIPS, NAVELEX, and R-1051H, it puts full AGC on the
>   6BZ6 and reduced (85%) on the 6AN5.  The 6AN5 is too hot
>   to touch, but the voltages indicate it's within design
>   maximum in the tube manual.
>
>   My Frequency Standard is another module that appears
>   to have been introduced in the middle models between
>   plain and H.  Its mode switch has INT, EXT(NORMAL),
>   and EXT(OVEN STBY) like the H, but it's discrete
>   transistors and does not include the automatic
>   switchover on loss of external input.  I can't find
>   any reference to its part number except the robot
>   sites that are eager to sell me one for a couple
>   thousand dollars.
>
> - When I last wrote about it, I had gotten my thermistor
>   sort of working.  It has become more stable, and I may go
>   on using it.  I got Bourns type 3006P and 3296 trim-pots,
>   and the 3296 is not feasible.  The 3006P drops right in.
>   The crystal had a clearly-distinguishable frequency
>   turnaround near 85C.
>
>   I still want to try an NTC since they're so cheap and
>   available.  I got a pack of 5 for a few bucks.  Anybody
>   want one?  10k at 25C, about 1.1k at 85C.  I'll epoxy it
>   inside the oven at the bottom, and for testing, bring the
>   wires out to an external breadboard that replicates the
>   oven control circuit from A1.  It looks like an easy fix
>   if your thermistor has gone pfft.  Just remove P2-3
>   (the pin connecting A1 to the original thermistor),
>   wire a 7.5k resistor from the pad to ground (8.2k if
>   R16 is 4.3k), and replace R13 with the new thermistor
>   plus 6.8k in series.  No trace-cutting.
>
>   I also got an SMD PTC thermistor from Mouser, but I have
>   second thoughts about mounting it.  It's more of a challenge
>   than the epoxy-dipped leaded NTC part.  Maybe solder it onto
>   a chip of copper-clad FR4 that's been scribed and manipulated
>   so copper extends past the laminate so it can be wrapped around
>   to the other side for wire attachment.  And it still would
>   have to be insulated from the oven can.  If I can make NTC
>   work, it will be the way to go.
>
> - I traced low sensitivity in the 12MHz band to a manufacturing
>   defect, a dry solder joint on the RF module's A2 turret strip.
>   Putting the turret back together is a pretty tense experience!
>
>   My spectrum analyzer and tracking generator made checking this easy.
>   (141T/8553B/8552A/8443A.)
>
> - Is it normal for 2MHz to be weak?  As in, 6uV for 10dB S/N
>   vs 2uV or less elsewhere?  I may be doing the turret dance
>   again.
>
> - By adjusting detents and sprockets, I have the chain drives
>   all synced up.  The MC code generator wafers are marginal,
>   but there doesn't seem to be much room for adjustment, as
>   some are on the CW edge, some CCW.
>
> - On the late models, the gain control mode is selected by
>   a switch on the front panel.  It seems to me that this makes
>   FSK aka RATT superfluous, because it's just USB+FAST.  Right?
>
> It has a ways to go, but it's definitely firing on all cylinders.
>
> Dave Wise
>
> >-----Original Message-----
> >From: David Wise
> >Sent: Tuesday, July 03, 2012 6:11 PM
> >To: 'R-1051 Discussion Group'
> >Subject: RE: [R-1051] Tools, and first assessment
> >
> >I bench-tested the motors in the RF module and the 1MC module.
> > The former seems okay, but the little gearmotor in the 1MC
> >needs attention - the brushes are worn down and the bearings
> >are squealing.  It appears to me that with some soldering and
> >finagling, I might be able to remove the baseplate, and then
> >get at the motor.  Is this the best way?  Is there a modern
> >substitute for the brushes?
> >
> >Thanks,
> >Dave Wise
> ______________________________________________________________
> R-1051 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/r-1051
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:R-1051 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>