[Boatanchors] newbie question

[Garey Barrell]

I say it depends upon just how many different tubes are in the equipment you want to service.  A decent tube tester will cost you at least 
$100 for even an emission type, up to several hundred for a good Mutual Conductance type.  Neither one will tell you for certain that a tube 
that tests good will work in the radio you are attempting to fix. "Short" and "Gas" tests are notoriously unreliable even in 'good' testers, 
and again, even a tube that tests 'good' may not work and leaveyou searching for a non-existent problem.  Most receiving tubes are available 
for $4-5 from reputable dealers.  PA tubes are another problem but troubles there are fairly easy to determine if the fault is the tube(s).

Buy at least one of each TYPE of tube in your radio. When they arrive, if the radio is working, swap each new tube into it and see if it 
makes things better, worseor just the same. If better, note and reverse the swap. Keep going through each tube until ALL of the 'new' tubes 
have been tested in the radio and found to make things better or just the same, replace all the original tubes and put the new ones on the 
shelf as 'tested spares'. (NOTE: Not ALL 'new' tubes are good! Reputable dealers test them before shipment, but ...)

If one or two of the new tubes tested noticeably better, leave it in the radio and order another.  When the new one comes try the same thing 
and if ok add it to your tested spares.

Now you have a REAL test procedure, and if your 'tested spare' doesn't fix the next problem, you know to look elsewhere.  If it does, leave 
it in and order a new spare. Not only have you found the problem, you have a part on hand to fix it!!

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

Tom Chesek wrote:
> I agree.  First use the tube tester to rule out a obvious bad tube then proceed to do the more tedious task of checking other circuit 
> components. If after that process you don't find a failure then source replacements tubes to test the circuit with.
>
> Tom K3TVC
>
>
>
> -----Original Message----- From: Bob Macklin
> Sent: Sunday, June 30, 2013 11:38 AM
> To: Glen Zook ; Bill Cromwell ; boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] newbie question
>
> THE PROBLEM I see is getting a stock of replacement tubes. And there is no longer a local drug store to run to to buy tubes.
>
> My position is that for a person that does not have a supply of replacement tubes available a tube tester is something to consider.
>
> In the past 10 years my Heathkit TC-3 has only found one bad tube. But it has helped me to determine I did not have a tube problem.
>
> Bob Macklin
> K5MYJ
> Seattle, Wa.
> "Real Radios Glow In The Dark"
>