Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

donate to eham
   Home   Help Search  
Pages: [1]   Go Down
  Print  
Author Topic: Tube testers; what to know and where to buy?  (Read 882 times)
KD0ZGW
Member

Posts: 1056




Ignore
« on: July 05, 2019, 05:41:08 AM »

Getting into fixing boat anchors.  I'm old enough to remember checking tubes from radios and TV's at the tube tester in the local drugstore.

Need coaching on what to look for in a tube tester for tube type ham equipment, what one should cost, and where to find it.  No hurry.

Thx in advance to anyone taking the time to offer advice.

KD0ZGW
Logged
KAPT4560
Member

Posts: 558




Ignore
« Reply #1 on: July 05, 2019, 08:34:48 AM »

 Mutual conductance-type testers are probably most accurate. The real deal is how the tube operates in the circuit. The surrounding circuitry has a lot to do with the tube performance and must be in good operating order to begin with.
 I think that the 1st sentence and the last paragraph in the answer says it all here:
 http://www.tungsol.com/html/faqs7.html
Logged
W1BR
Member

Posts: 4195




Ignore
« Reply #2 on: July 06, 2019, 07:41:43 PM »

Some reading material here:

http://tone-lizard.com/category/tube-testers/
http://www.alltubetesters.com/articles/tester_guide.htm

Also, if you Google search for that topic on AntiqueRadios.com you will find an endless list of discussions regarding that very subject.

Pete
Logged
KD0ZGW
Member

Posts: 1056




Ignore
« Reply #3 on: July 06, 2019, 07:54:03 PM »

thx for responses.  Got a bit of research to do now.
Logged
N8FVJ
Member

Posts: 908




Ignore
« Reply #4 on: July 07, 2019, 05:34:08 AM »

The inexpensive Allied/Knight 600B tester is excellent without breaking the bank.
Logged
AA4PB
Member

Posts: 15066




Ignore
« Reply #5 on: July 07, 2019, 07:15:53 AM »

My experience working in radio/tv repair in the 1950's and early 60's was that tube testers weren't very reliable. Basically, if it said the tube was "dead" then it probably was but if it said it was "good" then it may or may not be, depending on the circuit where it was used. This was especially true for tubes used in RF and oscillator circuits. When I overhauled a 5-tube console radio a few years ago I just replaced all of the tubes with new for about $25 from one of the antique on-line parts stores. That was less expensive than buying a tube tester anyway.
Logged

Bob  AA4PB
Garrisonville, VA
AC2EU
Member

Posts: 1501


WWW

Ignore
« Reply #6 on: July 07, 2019, 07:55:02 AM »

There are two basic types of tube testers; emissions and parametric.
The emissions type only checks if there is current flowing, that there is still sufficient electrons being ejected from the cathode.
The parametric tester checks for current and transconductance.

However, as most have already stated, tube testers are not the "definitive test" for tubes anyway. I only use one to verify that the tube in a bad stage is actually bad.
I only do that if I don't have a tube to swap in it's place.

The other use for a good tube tester is to check a bunch of random tubes in the box I just bought. 
Otherwise, it's not really something to use as a diagnostic tool, but to get a general idea of the tube quality.
Logged

W1BR
Member

Posts: 4195




Ignore
« Reply #7 on: July 07, 2019, 09:26:55 AM »

The most important functions that tube tester provides is showing shorts between elements or excessive leakage.

In most cases, the rig or radio is the best way to evaluate how well a tube performs. For example, rare and expensive 45 triode audio tubes may test weak, but may still work quite well in a vintage early 30's era AM consumer radio.

Most versatile testers are many of the Precision models. They are one step ahead of a basic emissions tester in that they apply an AC signal to the grid to determine a relative tube rating.  Along with a companion tube socket adapter, and the later charts, they will test almost any tube that was made, excepting transmitter types.

I have a Weston 981 (which was copied by Heath when they produced the TT-1)  and Hickok 800 in the shop... but my go to tester for quick evaluation is usually the Precision 10-54.  The late Alan Douglas published a good book on older test gear that covers  tube testers in detail.  Worth reading if you can borrow a copy.
Logged
KM1H
Member

Posts: 5516




Ignore
« Reply #8 on: July 10, 2019, 07:51:24 AM »

Here is a lengthy discussion on the Knight 600 series. As with most Knight products I would not take their accuracy as a given but as a decent go-no go indicator all in that mid level emission tester category do the job. The ONLY real test is comparing with a new tube IN CIRCUIT.
https://antiqueradios.com/forums/viewtopic.php?f=8&t=333168

The only non transconductance/emission tester Ive tested/owned before settling on Hickoks is the Jackson 648-S which tracked very close to my overhauled and calibrated Hickok 752A which I acquired from the National Radio IRS auction in 1992 and still use. I also have a TV-7A and I-117 for backup or on another bench....the 752A takes up a lot of room.

The S Jackson has charts available on line for even the end of the tube era and requires very little to service and ready for use. 

I gave mine to my #2 son Brian when he started getting into tube guitar and regular amps; started playing at 12. Soon he was building them while stationed in Germany in the USAF (MSEE)  and then when living there and Montenegro after retiring. His job had him travelling all over EU including Ukraine and Russia where he has found many sources including visiting Svetlana in St Petersburg where his girlfriend is from. He speaks German and Russian like a native.

There is a lot of discussion on line about the Jackson models and prices vary quite a bit.

Carl
Ham since 1955
National Radio 1963-69
Service Dept Tech, R&D Sr Engr Aide, Service Manager
Member of HRO-500, NCL-2000, NCX-1000 Design Teams
Logged
Pages: [1]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!