[ARC5] When a "Good" Tube, Ain't- AN/ARC-2 Success (long)

[Jack Antonio]

On 3/21/2014 12:56 PM, Richard Knoppow wrote:

>>> I do have several tube testers but seldom use any of them.
>>
>> Likewise here.
>>
>> Ken W7EKB
>
>      I must disagree about the usefulness of tube testers, IMO they can
> be quite useful although, of course, the final test is if the tube works
> in circuit.


I've developed the habit of running all the tubes in a set through a 
tube tester in the initial stages of troubleshooting, during the
"reconnaissance" phase, the looking for burned components, 
modifications, cut wires etc.

1. It gives a chance to inspect the tube for cracked envelopes, loss
of vacuum (white getter) or mechanical problems. Also a chance to
look at the pins for signs of corrosion.

2. It weeds out the open filaments, shorted elements etc.

3. It is a good way to check that the proper tube is in the proper
socket, sometimes a swap meet purchase has had random tubes put in
or tubes swapped around.

At this point I don't worry too much if a tube is weak, but I
do make a note of it, and will replace the tube once the radio
is alive and playing, after the troubleshooting phase.

After wasting an hour on an MN-26 once where I didn't check
the tubes, it is now an established ritual.

Jack Antonio
WA7DIA/4