[R-390] R-392 help

[Mark Huss]

That was my first thought, too.  That is why I tried Stand-By.  I think 
Barry is right.  Sounds like an AGC problem. 
I also own an R-390A from 1955, Origional Collins #2792.  And if anybody 
has a spare PTO they want to part with, I am buying. (the origional one 
has about a khz of 'slip' from wear).
As for the LS-166.  I actually need the UG-77 connector on it.  As a 
point of note about the tinny sound.  Researched this while stationed in 
Korea for the RATT Rig operators, who liked to tune in shortwave on the 
secondary receiver.  They couldn't use stereo speakers because 2nd LT 
'Crash' Rothman objected to the 'Unauthorized Equipment'.  The little 
600 to 8 ohm transformer is the main culpret.  Manually swept it using 
an audio oscillator and there is a nice rolloff below 300 hz.  Cured the 
problem by replacing the transformer with a 70.7 volt one, and stuffing 
the metal cabinet with fiberglass.  The ops were appreciative.  Said it 
sounded a lot better.  And 2nd LT 'Crash' Rothman was none the wiser.
R-392/URR, Stewart-Warner, Sn# 2681R, Order nr. 11653-PH-52.  And from 
the paint on the case, belonged last to the Radio PLT, Co B, 198 Sig.

By the way, has anyone else noticed how Collins slips these little 
things into their designs.  Like the seperate B+ pin on the Power 
connector of the R-392?  One would 'almost' think that somebody was 
thinking about making the R-392 capable of running AC for the filaments 
and seperate DC B+ for fixed operation.  Has anybody tried that? Note, 
It does not have the solid-state audio module.  Can't think why it would 
not work.  My little 4Amp open frame linear power supply gets mighty 
warm powering all those filaments!

John Bunting wrote:

> Mark,
>
> There are lot's of us R-392 owners out here.  Mine is a built by 
> Stromberg-Carlson Co. for Collins Radio Co. receiver I bought as a 
> "used repairable" from Fair Radio in 2000.  Been doing odds and ends 
> on it every once in a while and my most recent was setting the VFO end 
> points adjustment.  Now working on getting the zero point on each band 
> to be +/- .5KC.  I had bought a '392 carcass at the Shelby, NC hamfest 
> in 2002 and it had all the crystals left in it.  Now comparing the 
> crystal frequencies with a counter and installing the closer one into 
> my working receiver.
>
> When you turn the cal switch to CAL, a small relay located behind the 
> ANT bnc connector grounds the antenna input.  I wonder if that relay 
> hangs for the time you describe. You might try the following, cut a 
> 1/2" wide strip of white paper and slip it under the armature, using 
> an orange stick or something like it to force the armature against the 
> paper and then pull out the paper strip while still applying pressure. 
> Some times the residual air gap between the armature and the pole 
> piece will get crudded up and wont release.  It's a shot in the dark, 
> but easy to do. Hope it works.
>
> Good luck and 73, John, W4NET
> PS, the LS-166 is the correct speaker, but I'm not sure you would 
> really like to listen to it all the time as it has virtually no low 
> frequency response (sounds tinny to me).  I use an LS-7 with mine and 
> it sounds a lot better to me.
>
>