[Henry] Are 3B28's reliable??

Mon Feb 7 21:59:29 EST 2011

Got it, but mine is a plane jane 2K like Dan's but mine is serial #516, anyway the encountered opinions were about changing fron 3B28 to Solid state, that's my concern, I bought a couple of brand new 3B28's from tubesandmore.com but although they are same brand RCA, the color of the cloud looks more intense in one than in the other like a light purple as long as I recall and ocasionally some like internal lightnings.
The reason I'm dealing with this is because one day I turned it on and from the sudden it blowed the ceramic cap C12 and a couple more ceramic ones in the socket that connects the power supply cabinet with the RF module.

--- On Mon, 2/7/11, Dave Harmon <k6xyz at sbcglobal.net> wrote:

> From: Dave Harmon <k6xyz at sbcglobal.net>
> Subject: RE: [Henry] Are 3B28's  reliable??
> To: "'Milton Valerio'" <oligo_cr at yahoo.com>, henry at mailman.qth.net
> Date: Monday, February 7, 2011, 5:35 PM
> That's all a bunch of unsliced
> baloney. Don't use resistors or anything
> else....
> The 3B28 is a plug and play replacement for mercury vapor
> 866 rectifiers.
> The 3B28 has Xenon gas which may or may not glow slightly
> depending on the
> voltage and current.
> The big deal here is the 3B28 has no warm up time.
> If the 866 is not warmed up long enough the mercury will
> still be liquid and
> cause a short from plate to cathode. 
> Obviously, this isn't good. 
> 
> If the HV comes on before the mercury heats into a gas, you
> can always hope
> the fuse or breaker blows quickly enough and the cathode
> winding will not
> open and neither will the secondary of the HV transformer.
> The HV secondary and the cathode secondary will be shorted
> together by the
> liquid mercury.
> Of course...this is not supposed to happen.
> 
> So.....the best thing to do is use the 3B28's and don’t
> be concerned.
> You can get 3B28's from Frank Krize K5SVC. He has a store
> on the auction
> place.
> I've used him for years and always got the good stuff from
> him at fair
> prices.
> 
> If your amp was designed for 866 or 3B28 rectifiers, it
> will not have a step
> start feature to protect the sudden application of HV to
> the filter caps. 
> If you solid state the rectifier(s) the diodes will likely
> be destroyed by
> the sudden startup surge.
> The filter caps are like a huge glass of water....as long
> as you fill them
> gradually there will not be any problems....such as with a
> glass rectifier.
> With SS diodes, that glass of water is filled instantly and
> the diodes will
> likely be crowbarred.
> 
> An example is the 3K-A.
> It was designed for SS rectifiers and has a manual
> step-start feature that
> works.
> I bought one new in 77' and it's still going strong
> today.....34 years
> later.
> A true California Kilowatt.
> Dan will confirm everything above.
> 73
> 
> Best
> 
> Dave Harmon
> K6XYZ[at]sbcglobal[dot]net
> Sperry, Ok.
> 
> 
> -----Original Message-----
> From: henry-bounces at mailman.qth.net
> [mailto:henry-bounces at mailman.qth.net]
> On Behalf Of Milton Valerio
> Sent: Monday, February 07, 2011 3:05 PM
> To: henry at mailman.qth.net
> Subject: Re: [Henry] Are 3B28's reliable??
> 
> Yes that was another option but I have heard several
> encountered opinions
> regarding that, ones says that is just as simple as plug
> and play others
> says not, one need to put a resistor somewhere because
> resistance are
> differents etc so I'm affraid to make a mistake here but
> hey I feeled
> tempted to do it, yes on ebay you see them from time to
> time.
>  
> 
> --- On Mon, 2/7/11, Tim Kass <k8wbl at yahoo.com>
> wrote:
> 
> From: Tim Kass <k8wbl at yahoo.com>
> Subject: Re: [Henry] Are 3B28's  reliable??
> To: henry at mailman.qth.net,
> "Milton Valerio" <oligo_cr at yahoo.com>
> Date: Monday, February 7, 2011, 12:10 PM
> 
> I suppose they are also subject to be "gassy".  I have
> replaced my 866
> Mercury Vapor tubes with the 3B28 rectifiers...I believe
> that they may have
> a higher flash point, can take a bit more HV and current. 
> You also don't
> have to wait for them to warm up ... good luck...they do
> make solid state
> plug-in as well.  Surplus sales of Nebraska has them but
> are expensive
> through them...try Ebay..
>  
> 73, Tim K8WBL
> 
> --- On Mon, 2/7/11, Milton Valerio <oligo_cr at yahoo.com>
> wrote:
> 
> 
> From: Milton Valerio <oligo_cr at yahoo.com>
> Subject: [Henry] Are 3B28's reliable??
> To: henry at mailman.qth.net
> Date: Monday, February 7, 2011, 12:01 PM
> 
> 
> Hi to all, after having some problems with my 2K I though
> about how reliable
> were NOS 3B28's?
> I got a new pair of these but after put them in service I
> noted that the
> purple color was not the same for both and also one use to
> show like
> internal "lightnings" I always believed that NOS are bullet
> proof but is
> that true or its a matter or luck.
> 
> Milton
> 
> 
>       
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