[Hammarlund] 5R4WGB signs of white fog inside

[Bob Camp]

Hi

The whole issue of gas in tubes is a bit complex. Mercury vapor is  
commonly used in rectifiers to improve their performance. If anything  
the gas may make the rectifier work a little better. Eventually the  
gas will strip the coating from the cathode and the emission of the  
tube will drop off. Even with the tube full of air I do not see a  
reasonable way it's going to damage anything before it dies.

There are a limited number of ways a rectifier can damage the radio.  
One way is if the filament shorts out and takes the transformer with  
it. The other would be if the filament shorts to the plate when it  
goes. This would put AC on the filter capacitor. In either case the  
fuse on the  radio *should* pop before damage is done. I have seen a  
lot of rectifier tubes fail over the years. I have *never* seen one  
do damage to the equipment when it failed.

About all I would recommend is to check the size and type of the line  
fuse. This is a good idea on any radio under any circumstances.

If you want to watch what's going on with the tube then you might  
check the B+ voltage. When it starts to drop off by 10% or more then  
replace the tube.

     Enjoy!

         Bob Camp
         KB8TQ



On May 15, 2005, at 4:15 AM, Oskar wrote:

> Many Thanks Bob,
>
> of course I have second tube, but I will wait
> for clear malfunction of the rectifier.
> I hope that it impossible that leaking rectifier
> do any damage in electrical circuit?
>
> 73,
> Oskar
>
> --- Bob Camp <ham at cq.nu> wrote:
>
>> Hi
>>
>> The getter turns white as it absorbs gas. The tube
>> you have is slowly
>> leaking. If this was an amplifier tube I would worry
>> about it. In a
>> rectifier it is not as big an issue. It probably
>> will keep leaking
>> and eventually fail. I would recommend shopping for
>> a replacement if
>> you don't have one on the shelf. Depending on how
>> you approach the
>> hobby there are also ways to replace the tube with a
>> solid state
>> equivalent ...
>>
>>      Enjoy!
>>
>>          Bob Camp
>>          KB8TQ
>>
>>
>>
>> On May 14, 2005, at 2:02 PM, Oskar wrote:
>>
>>
>>> Hello,
>>> In my SP-600 is installed JAN Raytheon 5R4WGB
>>> rectifier.
>>> Inside in borders of getter I see signs of white
>>>
>> fog.
>>
>>> Rectifier is working properly, is in this
>>>
>> situation
>>
>>> necessity of changing tube?
>>> 73,
>>> Oskar
>>>
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>>
>
>
>
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