(27-11-2016, 05:21 PM)Sparks Wrote: The meter wasn't sticky though, and worked quite smoothly, but the readings didn't make sense. What still puzzles me is reading the scale (See below). The Replace and Good sections with the short bit in between seem to indicate that the higher the reading, the better the valve is, i.e 0% to 100%. (I often see valves advertised as "tests at .....%" But it says mA/V above it. Also, if I test a valve that has a gm of 3 mA/V, should the needle only go up to that figure, or go right up into the green section that starts at 5.6. If someone could explain it to me in clear language, I would be very grateful, but I have never had any experience of valve testers before! To put it even more simply, I don't know what I am reading on the scale, the goodness of the valve in percentage, or the actual mA/V.
Bob
For a mutual conductance reading in mA/V consult the Avo valve data for the valve you want to test and set the anode/screen/heater switches etc accordingly, set the mA/V control to 100, set the anode selector to normal then plug the valve in, once the valve has heated up back off the meter current to zero then set the mA/V switch to mA/V, press the key switch to mA/V and read off the top scale (0 to 10) that's the valves mutual conductance figure in mA/V at that moment in time.
The Replace/Good test does not give a mutual conductance read out, to do this test follow the same procedure given above so far as and including backing off the meter current to zero then set the mA/V control to the mutual conductance figure given in the Avo valve data for the valve you want to test, re adjust the backing off control to ensure the meter current still reads zero, press the key switch to mA/V and make a judgement from the Replace/Good scale.
Hope this helps.
Lawrence.
