Paul -
I don't think it's quite fair to diss Drake because some clown stuck an
ice-pick in a tube socket! :-)
I ran three A / B lines back in the 60's on autostart teletype for a
half-dozen years. This consisted of 24/7 operation, with full power
transmissions often exceeding 30 minutes. There was a small fan on the
back of each PA cage, and one fan blowing across the back of the desk.
The receivers were crystal controlled, and each pair was locked together
on 14.100 MHz. 170 shift of course, with 400 Hz b/w.
The PA tubes would last about two years, ( end of life determined when
output power dropped to 100W on 20M,) and only ONE failure, a 12BY7
filament that just opened up.
The 2-B is a great, reliable receiver, but ... I suspect the R-4As have
all been fixed, fixed ....... :-)
73, Garey - K4OAH
Glen Allen, VA
Drake 2-B, 2-C/2-NT, 4-B, C-Line&
TR-4/C Service Supplement CDs
<www.k4oah.com>
[email protected] wrote:
The problem is the tube socket itself. Upon magnified examination
I observed that the inserts for the tube pins have been mangled by
someone pushing something down into them that spread and twisted them
and all but eliminated the nice "friction fit" around the tube pins.
As a result the tube fits too loosely and occasionally loses contact.
SIDE NOTE: I bought four receivers over the past 2 months
but *ONLY ONE* has operated flawlessly from Day 1 with no work having
been done on it, and that one is the 1961-vintage 2B, s/n 2052, which
means it was the 52nd unit built. All three of the R-4A's have
problems, problems......... ;-)
Hmmmm, from a longevity standpoint maybe Drake should have quit
while they were ahead..... ;-)
73/arf,
Paul, K4MSG
In a message dated 9/15/2010 8:22:21 P.M. Eastern Daylight Time,
[email protected] writes:
*/Hi Paul,/*
Years ago I purchased an old Heathkit SB-102 transceiver as a
back-up set, and all was well until one day it stopped "hearing"
on CW on a consistent basis. There was an intermittent that drove
me nuts!
I checked the schematic for all of the usual "suspects", and
determined that the issue was with the crystal oscillator/BFO
stage---I even pinpointed (on paper, anyway!) the exact area where
I thought the trouble was coming from...yet to the eye everything
looked A-OK, & the components checked-out.
The design of the thing incorporated printed circuit mounted tube
sockets. In desperation, I re-heated just that contact point at
the socket that I thought was causing the intermittent. Lo &
behold, I guess the heat caused enough solder to flow in the
socket that bridged the gab, & the intermittent was gone forever.
I think re-heating those socket pins is probably a good idea.
/*~73~ de Eddy VE3CUI - VE3XZ*/
/**/
********************************************************
----- Original Message -----
*From:* [email protected] <mailto:[email protected]>
*To:* [email protected] <mailto:[email protected]>
*Sent:* Wednesday, September 15, 2010 3:49 PM
*Subject:* Re: [Drakelist] R-4A anomoly
Just to reiterate from the original email: Different
tubes *WERE* tried (including two NOS) and
loosening/tightening the tube socket & PCB mounting screws.
More work on this tonight.
Meantime, I ordered a new 7-pin,
bottom-mount-with-grounding-lugs socket from Antique Elex and
if worse comes to worse I'll just replace the socket. It
is possible that one of the socket pins has actually separated
into two pieces, upper & lower, that lose contact when the
tube heats the socket and the metal expands and changes
shape. It's rare, but I have seen it before.
And I'll stick an extender in it tonight and compare
voltages top & bottom.
73/arf,
Paul, K4MSG
------------------------------------------------------------------------
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
_______________________________________________
Drakelist mailing list
[email protected]
http://mailman.zerobeat.net/mailman/listinfo/drakelist
