[Boatanchors] Mercury Rectifiers

[Rob Atkinson]

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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