This is good advice from Bob, if you must use the old tubes that you don?t
really know if they are worn out anyway, I would just get a pair of new
ones if it were me, I am talking from experience.
The only reason I went through the gettering process was that I had a New
never used SB-221 and brand new Eimac 30 year old tubes and thought it would
be nice to use those old tubes. The getting went fine, one tube was blue
for a while so I thought all was good. I put those tubes in my Six meter
mono band SB-220 and one tube flashed over at 1kw out, took out the
rectifier board and various capacitor with a pretty big bang, that took a
few minutes off my life: -)
So unless you are attached to those tubes for sentimental reasons I would
dump them or follow the instructions by PA0FRI at the least.
Also as mentioned the components used back then were not so good, so do
update the amp with Harbach boards etc.
http://www.harbachelectronics.com/main/page_products_sb220__sb221.html
If you want to keep the and use it, do the recommended modification and
updates. Not sure you need the "Parasitic Suppressor Kit", never really
proven to work in my mind, also the "Soft Start" probably not need for this
amp, but the "Soft Key board" needs to be done if you are driving it with a
solid state rig and also the "Rectifier/Metering Board" from Harbach would
be a really good move.
-Mike, K6BR
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of rbethman
Sent: Saturday, November 05, 2011 4:08 PM
To: amps@contesting.com
Cc: R Johnson
Subject: Re: [Amps] Gettering 3-500 Tubes
I wouldn't be concerned with "Gettering".
*IF* there is air leakage into the tubes, they will show a cloudy gassy
look.
Go ahead and try them as they are after you've gotten the rest sorted out.
*IF* it was me, I'd replace the capacitors in the HV section. 20 years
is a long time, and Heath didn't always use the "High" end parts.
Bob - N0DGN
On 11/4/2011 12:05 AM, R Johnson wrote:
> I have just been given an old SB-220. It has been sitting in an attic for
20+ years.
>
> I have removed the tubes and have been bringing the voltage up slowly
> to reform the filter caps. When I get to 120V in and the caps aren't
steaming
> and/or blowing smoke I'll be ready to check it with the tubes installed.
>
> I know that the need 3-500's will need to be "Gettered" to remove any gas
diffusion
> thru the metal to glass seals on the tube.
>
> I read a procedure on (probably) on this list on how to do it.
> Now that I need it, I can't find it.
>
> Does anyone remember this thread within the last 3 or 4 months ???
> If not,can any recommend how to cook these tubes in ???
>
> TNX es 73
> Bob, K1VU
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
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