From: "David Austin" 
Subject: [drakelist] Re: Relay not pulling in (TX4C)


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Hi again folks,

With apologies, please ignore last email. The relay has now started =
pulling in. Did nothing except leave the TX switched on! Found this =
article on the web:

http://www.wb4hfn.com/DrakeArticles/TechTips/TroubleshootingAntRealy.htm

From this, I think I may well have a gassy tube, as the relay voltage is =
still on the low side. Will try a substitute 6EV7.

Sorry to have wasted everyone's time, if anyone started to troubleshoot =
this one for me!

73,

David
G4GTP
  ----- Original Message -----=20
  From: David Austin=20
  To: Drakelist=20
  Sent: Wednesday, February 11, 2004 9:28 PM
  Subject: Relay not pulling in (TX4C)


  Hi all,

  Another plea for help! I have replaced relay K1 with a 2.5K solenoid =
as per the updated T4XC circuit, as I discovered the old relay (old 15k =
solenoid version) to be open circuit. Of course I also added the =
necessary 1.5K resistor in series. All as per advice from Garey - K4OAH =
(for which many thanks Garey).

  Now, when I go into tune mode, the relay will not pull in. There is =
only 30V across the solenoid, and should be nearer 40V I believe from my =
calculation (assuming plate resistance =3D 11.5K). I suspect the VOX =
control tube is not conducting fully. Voltages (in Tune mode) on V10 are =
as follows:

  Pin 6 plate:    215v (manual says 170v)
  Pin 7 grid:    -2mV (manual says -100mV)
  Pin8 cathode:  +880mV (manual says -660mV)

  R70 measures spot on 82ohm
  Have checked all outputs on AC4 and these all seem to measure fine.

  Any thoughts on where to look for likely problem? Could diodes CR13 or =
CR14 have blown and if so, what would be effect? Could anything have =
been taken out when the solenoid blew (can't see anything vulnerable) or =
could the solenoid originally have blown due to failure of other =
components in this area?

  Hoping someone might give some pointers!

  73 to all
  David
  G4GTP

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Hi again folks,
 
With apologies, please ignore last =
email. The relay=20
has now started pulling in. Did nothing except leave the TX switched on! =
Found=20
this article on the web:
 
http://www.wb4hfn.com/DrakeArticles/TechTips/TroubleshootingAntRe=
aly.htm">http://www.wb4hfn.com/DrakeArticles/TechTips/TroubleshootingAntR=
ealy.htm
 
From this, I think I may well have a =
gassy tube, as=20
the relay voltage is still on the low side. Will try a substitute=20
6EV7.
 
Sorry to have wasted everyone's time, =
if anyone=20
started to troubleshoot this one for me!
 
73,
 
David
G4GTP


---