[Heathkit] reactivation of a 3-500

[Chris Kepus]

Just returned from other duties and checked email.  

Was extremely gratified to see all the helpful comments.  Thanks to all!!
Also my hopes that my 3-500's may be OK have been bolstered.

Will do some additional reading in Eimac Care and Feeding and come back with
additional questions.  Amazing how one question always begets more
questions!  Hi Hi.

Happy weekend to everyone.

73 and tnx agn,

Chris
W7JPG








-----Original Message-----
From: Heathkit [mailto:heathkit-bounces at mailman.qth.net] On Behalf Of Garey
Barrell
Sent: Friday, May 16, 2014 7:52 AM
To: Ulrich Graf; heathkit at mailman.qth.net >> Heathkit Reflector
Subject: Re: [Heathkit] reactivation of a 3-500

Uli -

The 'heating' must be more than just the filament.  You need plate
dissipation.  The plates need to be heated to red hot for some period of
time.  IF these are EIMAC tubes there is a coating on the plates that is
'activated' by red heat.  I have had tubes recover after only an hour at red
heat.  Be sure and keep air going, especially on the glass/metal seams of
the pins and plate cap..

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

Ulrich Graf wrote:
> Hi to the list,
>
> got an SB-1000 linear amplifier recently second hand. While activating 
> PTT I noticed that the bias current is continuously increasing. Bias 
> network seems to be ok. So the tube must have drawn some gas. How can 
> I activate the getter the easiest way to reuse this tube again? Many 
> hours of heating do not work.
>
> vy 73, Uli, DK4SX
>

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