[Boatanchors] Mercury Rectifiers

[David Knepper]

Anyone hear of hash?  While we are going nostalgic, why are we using solid 
state audio enhancement.  Is this hypocrisy or what??

Did you know when mercury vapor tubes flash over, you have to replace them?

I use mercury vapor tubes only in my pre-WWII Collins transmitters.


David Knepper, W3CRA/W3ST
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----- Original Message ----- 
From: "Rob Atkinson" <ranchorobbo at gmail.com>
To: "Jim" <jbrannig at verizon.net>
Cc: <boatanchors at mailman.qth.net>
Sent: Monday, April 23, 2012 5:15 PM
Subject: Re: [Boatanchors] Mercury Rectifiers


you'll like this:

http://w3np.com/images/meissner/866glow493.jpg

rob
k5uj

On Mon, Apr 23, 2012 at 3:59 PM, Jim <jbrannig at verizon.net> wrote:
>
> I miss the pulsing blue glow of 866's in a darkened room.
> The slight buzz served as a side-tone.....
> The radio seemed to breath and be alive..........
>
> Alas, solid state rectifiers are more efficient and don't "flash back"
>
> but I miss the pulsing blue glow....
>
> Jim
>
>>
>>
>> Of course, the other "fix" is to replace the 866 tubes with 3B28 types.
>> No mercury vapor problems, no long preheat required, etc. 3B28 tubes
>> are Xenon filled, and don't glow nearly as much as 866s do (they do
>> glow, just faintly), but they are a whole lot more forgiving. And, if a
>> bit of heresy may be permitted, a couple of diode stacks from otherwise
>> defunct microwave ovens will make a tidy replacement, give a bit more
>> B+, save some cabinet heat, and some electricity (no filament
>> transformer), and are "instant on". I guess it depends on whether a
>> person cares how something looks, or how it works. Each to his or her
>> own. I replaced the 866 tubes in my old Heathkit "Warrior" amplifier
>> (4 X 811A), first with 3B28s and then later with diode stacks - and
>> never looked back.
>>
>>
>> - Jim, KL7CC
>>
>>
>>
>> Nick England wrote:
>>> I sent John a copy of the relevant pages in the RCA Transmitting Tubes
>>> manual TT-4 which has a very good discussion of the topic. RCA says
>>> Preheat and Condition.
>>> Summary -
>>> Preheat with normal filament voltage at least 30 minutes with no anode
>>> voltage.
>>> Let cool and condense.
>>> Then Condition at normal filament voltage and apply 1/6 normal anode
>>> voltage (after the usual mandatory recommended warm-up period) for 5
>>> minutes. Gradually increase the anode voltage over 30 minutes. If a
>>> flashover occurs during this process, reduce anode voltage until
>>> flashover ceases, maintain this reduced voltage for a few minutes,
>>> then resume the treatment.
>>>
>>> http://www.we0h.us/Amateur_Radio_stuff/Books/RCA-TT-4-Transmitting-Tube-Manual.pdf
>>>
>>> cheers,
>>> Nick K4NYW
>>>
>>> On Mon, Apr 23, 2012 at 11:31 AM, J. Forster <jfor at quikus.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> Is there an issue with Mercury pooling in rectifiers, like the 866, in
>>>> long term storage that would cause them to blow over more easily?
>>>>
>>>> If so, is there a fix?
>>>>
>>>> Best,
>>>>
>>>> -John
>>>>
>>>>
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