[R-390] Stinkin' PTO !!

[Phil Atchley]

Good afternoon all.
Well, the odyssey of the Cosmos PTO lives on.  I repaired the end point =
coil
this morning and was able to set the end points F.B.

However, earlier when I checked the linearity at the 100KC points it =
looked
'pretty good, running typically 200 CPS to 1 KC off.  However, the 600 =
KC
point was OVER 2 KC out and I figured I could correct this with the
correction adjustments.  WRONG!=20

Taking my time and after tuning on this thing for perhaps 3 hours in a =
radio
room with an ambient temperature of 95 degrees (WITH the Air Conditioner =
on
full bore) I got up to the frequency of +570 KC (that is with adjustment
screws centered in the window).  Up to this time the tuning had gone =
pretty
good with most adjustment screws only requiring a turn or two in one
direction or the other. At this point the PTO tuning became very stiff =
and
the adjustment screw had NO affect on frequency when tuned either way.  =
I
even backed the adjacent screws off to make sure they weren't binding or
dragging.  So I checked the next frequency, same way for the next couple
steps. =20

Stiff tuning and the corrector has NO affect!  At this point I stopped =
and
threw in the towel.  (The screws adjusted earlier were rechecked and are
still good).

As I said before, though it looked nice on the outside, this PTO was no
virgin, at least around the end point coil.  I suspect that either the
Teflon disk or the "screw disk" is damaged.  That or there is another
problem in that area.  I have no intention of going that deep into the =
PTO.
The man I got the R-390A from said he has another PTO and I'm going to =
give
that one a try. =20

In the meantime, I have the time to pull the RF deck and check it out
thoroughly.       =20

73 de Phil, KO6BB

****************************************************
*  DXing THE WORLD WITH THE FOLLOWING EQUIPMENT.   *
*  RECEIVERS:                                      *
*    '67 EAC R-390/URR Surplus Receiver with a     *
*            HAMMARLUND HC-10 Sideband adapter.    *
*    YAESU VR-5000 Wideband,  REALISTIC DX-392.    *
*    Home built Longwave "Hybrid" CW receiver.     *
*    Others which pass thru or are waiting repair. *
*  ANTENNAS:                                       *
*    Coil Loaded 18.5 Meter Long Sloper.           *
*    Roof mounted Hustler 6BTV 6 band Vertical.    *
*    Scantenna Scanner antenna at 7 Meters high.   *
*  LOCATION: Merced, Central California.           *
****************************************************




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