Building a Valve Characteristic Tester 'Lampemeter' - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

efeemeka · 30th Nov 2020, 5:55 pm

Hello good afternoon, I am progressing in this assembly, I have already been able to put it into basic operation with triodes and I am very happy with the result. some ferrites distributed strategically and the triodes go with fairly uniform curves, later I will make the source of H.T. for screen supply. As it seems to be usual, I had some problems with the usb-rs232 cable or adapter, because as said there are 2 types of internal ChipSet, and it is not that the one that causes problems does not work, it is that out of 10 times it is pressed, only one works . was to put the appropriate serial adapter and everything worked correctly, I have put in some voltmeters and ammeters for monitoring filaments and values that could be useful at a quick glance. a lot of free time work hehe, but it's worth it, I physically check the validity of the tube in shorts and parts with other testers and then I pass it the tube to the tracer. I have some doubts in the interpretation of the resulting numeric text values, I assume the tube and load life is determined by the transconductance value displayed as Gm = mA / v. It would also be good to have some reference graphs, or a table (grid) with the values of the most common tubes, to fill in the values needed by the manufacturer without looking at datasheet's, because a lot of time is wasted looking and looking for values. thanks and good day.

https://www.dropbox.com/sh/i43mq0ob4...BqFxj9dla?dl=0

efeemeka · 2nd Dec 2020, 5:19 pm

Hi good afternoon again.

I tried the oscilloscope output, as indicated in the instructions and there my luck ended.

I did not get any curve-like results on the screen of a promax oscilloscope with dobke trace and button / mode X, Y. if I put the circuit in oscilloscope output mode,

flashing the red diode as indicated, then I put a probe to the output of Anode as indicated, and another probe to pins 1 or 7 of the TCL chip,

but something I must not of be doing fine, i am not getting graphical correctis results on the oscilloscope. maybe it is only done with a single probe? and channel? while I tested it with the 2 channels, and 2 probes.

something does not go well, some clue or concrete procedure for it? my experience with the oscilloscope is basic.
thanks
Joseph

30th Nov 2020, 5:55 pm	#21
efeemeka Diode Join Date: Nov 2020 Location: Madrid, Spain Posts: 5	Re: Building a Valve Characteristic Tester 'Lampemeter' Hello good afternoon, I am progressing in this assembly, I have already been able to put it into basic operation with triodes and I am very happy with the result. some ferrites distributed strategically and the triodes go with fairly uniform curves, later I will make the source of H.T. for screen supply. As it seems to be usual, I had some problems with the usb-rs232 cable or adapter, because as said there are 2 types of internal ChipSet, and it is not that the one that causes problems does not work, it is that out of 10 times it is pressed, only one works . was to put the appropriate serial adapter and everything worked correctly, I have put in some voltmeters and ammeters for monitoring filaments and values that could be useful at a quick glance. a lot of free time work hehe, but it's worth it, I physically check the validity of the tube in shorts and parts with other testers and then I pass it the tube to the tracer. I have some doubts in the interpretation of the resulting numeric text values, I assume the tube and load life is determined by the transconductance value displayed as Gm = mA / v. It would also be good to have some reference graphs, or a table (grid) with the values of the most common tubes, to fill in the values needed by the manufacturer without looking at datasheet's, because a lot of time is wasted looking and looking for values. thanks and good day. https://www.dropbox.com/sh/i43mq0ob4...BqFxj9dla?dl=0

2nd Dec 2020, 5:19 pm	#22
efeemeka Diode Join Date: Nov 2020 Location: Madrid, Spain Posts: 5	Re: Building a Valve Characteristic Tester 'Lampemeter' Hi good afternoon again. I tried the oscilloscope output, as indicated in the instructions and there my luck ended. I did not get any curve-like results on the screen of a promax oscilloscope with dobke trace and button / mode X, Y. if I put the circuit in oscilloscope output mode, flashing the red diode as indicated, then I put a probe to the output of Anode as indicated, and another probe to pins 1 or 7 of the TCL chip, but something I must not of be doing fine, i am not getting graphical correctis results on the oscilloscope. maybe it is only done with a single probe? and channel? while I tested it with the 2 channels, and 2 probes. something does not go well, some clue or concrete procedure for it? my experience with the oscilloscope is basic. thanks Joseph