Tell me about my new Tube Tester (AVO Mark IV)

Today I scored some more NOS tubes, and a tester to boot! All of this was free of charge (I insisted on paying, but they would not accept)!


Anyhow, this tester should be useful for testing all the NOS tubes I obtained in the last week. These include 3 new Mullard 12AX7s (10M series), 2 GE 12AY7s, some Marconi 12AX7s, a pair of Sylvania 6L6GCs, German Siemens 12AT7s, and many others! I will probably start another thread on this since some of the labeling is confusing. For example, the Mullards came in Siemens or Sylvania labeled boxes, with B & L labels, and I can't find any info about these. Also, just for my own curiosity, I would like to ID years of production, etc. (I am a very curious person!)!

The biggest issue for now is learning how to use the tester. I have all the manuals, and a whole bunch of other reference data (this gentleman gave me a GE tube manual, and several others including a tube cross-referencing guide and several AVO books).

As far as I know, the tester is in fine working order (even has a 3-prong plug). However, before I plug it in, I am wondering what I look for. Then, how do I go about using it? Do I just plug in a tube and "hit go?"

I am nearly new to the NOS tube thing, and completely new to tube testers, so any help would be appreciated.

Thanks!!!

 

Thanks to all!!

I now realize that this is an expensive and complex tester, but it came to me free (it was going to be trashed). This was the only one

I fired up the AVO, and followed the instructions, step by step. I used a sovtek 12AX7 tube, just in case something went wrong (not sure when I'll feel comfortable testing the Mullard 12AX7s or Sylvania 6L6s).

I got through the initial stages just fine, but have just a couple of questions:

Step 6: set the A1A2 normal/unlimited switch to the appropriate position for the value under test.

What does this mean?

I quite at this point, and this is just before testing of the mutual characteristics comes. I read through that part, and it looks pretty simple, but I wanted to be sure and have the A1A2 switch set correctly. I will continue to look through the manuals, but any quick tips would be great!!

Thanks again!!

 

Okay, here is what the manual says:

When testing valves having dissimilar double electrode assemblies it is necessary to limit the anode voltage on the selection not under test. The A1A2 normal position on this control in conjunction with the electrode selector switch, provides the facility for inserting a suitable limiting resistor in the appropriate anode circuit. Thus when testing double valves (triode hexodes, triode pentodes, etc.) this control is switched to the A1A2 normal position. For single and double valvles having identical sections, this control is switched to the Unlimited position. The control is inoperative when testing diodes, rectifiers, etc.

I interpret this teo mean that it should be in the umlimited position for testing 6L6s, 12AX7s, etc. since these either have only a single element or two identical elements, right?

Thanks!!