[R-390] They followed me home <GRIN>.

[Barry Hauser]

Hi Phil

Yeah, those radios have a way of finding you, don't they. ;-)
----- Original Message -----
From: "Philip B Atchley" <ko6bb@juno.com>
To: <r-390@mailman.qth.net>
Sent: Saturday, August 24, 2002 6:51 PM
Subject: [R-390] They followed me home <GRIN>.


> Hello all.
>
> Well, today Don and I drove up to Palo Alto and picked up our R-390A's.
> Both turned out to be EAC units from the FR-36-039-N-00189 (E) Contract.
> SN's 6137 and 3715.
>
> I haven't fired em up yet as I believe in the old adage, "Haste makes
> waste", especially in regards to old tube gear.

That's true -- I violated the indoor rauchen verboten rule twice in one
month after no smokers for a few years -- due to skipping the pre-nuptuals.
However, one was WWII vintage tube -- a BC-314 which took a drag on a
resistor (If you got 'em, smoke 'em.) and the other was a 70's vintage HP
scope - solid state. Can't find what puffed on that yet.  The older SS stuff
is starting to show the equivalent of black beauties -- like dipped
tantalums.  Take your time, go through the numbers.  I violated this and got
violated.

>
> QUESTION 1: Seeing as how these units have the rectifier tubes in place,
> how high do I need to bring the Variac before they will start conducting
> enough to start forming the caps, at least some?

You can plug in some diodes into the tube sockets temporarily.  As I recall,
the rectifier tubes don't start conducting until 90 volts, which is a bit
too high to truly accomplish a slow resussitation.

> They are both in good condition, with meters, all covers and so forth.
> The #3735 "looks" much nicer on the front panel, has IEC tube shields,
> regulator tube etc. As I haven't pulled them yet, I'm not sure if all the
> modules in either unit are original or not.  BOTH units have the 26Z5
> rectifiers in placerather than sand-state devices.  Not sure how good
> they are.

Test all the tubes before powering up, especially attentive to shorts.  As
you know, can't do a quality test on shorted tubes or you'll smoke the tube
tester.
>
> Don has already told me that I can pick-N-choose modules to make myself a
> 'Best' set as he know mine will get a lot of use.

That's sporting, and makes sense.  Only problem is with your extreme DX'ing,
you'll probably suck in all the signals on the Left Coast through your
sloper and leave nothin' for nobody else. ;-)
>
> QUESTION 2:  One unit has what appears to be a Collins PTO, the other a
> Cosmos unit.  Assuming they both work well, which one should I put in "my
> keeper"?

The Cosmos is probably newer, but ... get some other opinions.

>
> I intend to run both units up and give them a thorough checkout before
> doing a complete re-cap.  They were supposed to both be playing when put
> in storage two years ago, though he said both had problems on certain
> bands.

Open up the xtal deck and check that all the crystals are there and firm in
their sockets.  Also DeOxit the pins and the socket contacts.  Some of
these, particularly the EAC, have a tendency to loosten up.  They can be
tightened by pressing down on the biting edges to make, in effect, the hole
smaller.  Lately, I've come across a number of bad crystals.  Refer to the
xtal usage chart or xtal deck schematic for which xtals apply to which
bands.  Most all are used on more than one.  Also, the trimmers may be
oxidized a bit, and just touching them will bring the band back to life.  Or
it's something else, like the mech. synch/alignment -- but check the xtals
and trimmers first.

Good tweaking!

(Are you going to rig yours for "lowfering"?)

Barry