I think the humidity requirement of the test set is more for safety reasons than for equipment operation. If the set is properly grounded the humidity should not be a factor. The thinking may be that when the humidity is lower the body tends to build a static charge. Since the lateral panels are open on the side of the test set, there may be the possibility that an arc might occur from some of the exposed components to the fingers if you were to get that close to it. There are times when you have to make adjustments such as calibration and zeroing of the current readings prior to checking those values on the test cards. This is just my opinion but it seems to make sense.
Greg
Greg
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Hello ! Good year every body .
I have a L3-3 used but in good condition!
It is a very good machine !
I have very "brain storming " with imself for understand who calibrate and working!
Yes some pb occurs Pot VG1 -10V burns OK Replace easy .clean switchs
I can't open the .docs files
someone ideas ?
Sorry for my poor english
phil
I have a L3-3 used but in good condition!
It is a very good machine !
I have very "brain storming " with imself for understand who calibrate and working!
Yes some pb occurs Pot VG1 -10V burns OK Replace easy .clean switchs
I can't open the .docs files
someone ideas ?
Sorry for my poor english
phil
docx files
I think the files you meant are in docx format. That's a new word format, but you can't read it if you use an old Word version like I do (in my case Word 2002). There is a free translation program called docx converter. If you cant find it, just send me a private mail with your email address.
I think the files you meant are in docx format. That's a new word format, but you can't read it if you use an old Word version like I do (in my case Word 2002). There is a free translation program called docx converter. If you cant find it, just send me a private mail with your email address.
Test Card Notes
I have attached a file that contains all the translated notes on the test cards. It is very important when you check miniature tubes (Solder in types). The one column has the Russian language and to the right is the English translation. Tried to clean up the English as best I could, it seems the terminology is not consistent throughout. Do not know if anyone has to test the miniature tubes so I’m posting this just in case. Also, damage could be done to the test set or the tube if the notes are not followed. I would also double check the tube schematic to the test card in case there is a typo on the test card itself. I have only checked a couple and they worked fine.
I have attached a file that contains all the translated notes on the test cards. It is very important when you check miniature tubes (Solder in types). The one column has the Russian language and to the right is the English translation. Tried to clean up the English as best I could, it seems the terminology is not consistent throughout. Do not know if anyone has to test the miniature tubes so I’m posting this just in case. Also, damage could be done to the test set or the tube if the notes are not followed. I would also double check the tube schematic to the test card in case there is a typo on the test card itself. I have only checked a couple and they worked fine.
Refined Calibration Procedures
I have been working on cleaning up the machine translated calibration procedures and the test set calibrations prior to checking the electron tubes. It will be step by step instructions. Still need to double check for correctness. Hope to have it posted sometime this weekend. So stay tuned.
I have been working on cleaning up the machine translated calibration procedures and the test set calibrations prior to checking the electron tubes. It will be step by step instructions. Still need to double check for correctness. Hope to have it posted sometime this weekend. So stay tuned.
Simplified Instructions
As promised I have attached the simplified English calibration procedures. They include the preliminary calibration which is accomplished prior to checking any test card, the complete test set check and calibration and a scale conversion chart. The preliminary calibration needs to be accomplished prior to checking the tube (Pins inserted into test cards) for every test card to calibrate that section of circuitry in the test set. Not doing so will give you a false reading and may make a bad tube look good or visa versa.
I hope you find this information useful.
Greg
As promised I have attached the simplified English calibration procedures. They include the preliminary calibration which is accomplished prior to checking any test card, the complete test set check and calibration and a scale conversion chart. The preliminary calibration needs to be accomplished prior to checking the tube (Pins inserted into test cards) for every test card to calibrate that section of circuitry in the test set. Not doing so will give you a false reading and may make a bad tube look good or visa versa.
I hope you find this information useful.
Greg
Thanks Greg. So you actually did the calibration of the S board (the last twe tests in the 'Simplified Cal. Proc file) like this as well? I used a German translation that has similar instructions (so it should...). On my L3-3, doing the test ‘Calibration of the grid-plate transconductance “S” doesn’t work. If there is no tube 15 inserted (as instructed) I get zero reading, both on the separate multimeter connected to pin 6 and the L3-3 meter itself (with S toggle in calib mode and while pressing the measure button). Maybe I do something wrong but I tried several times following both the German manual and yours. Even if it would work, the text feels unclear. Is the idea to first set 120mv with the external meter, set the L3-3 meter on 120 readout with the calibration screw next to the S toggle and then lower the voltage to eg 100mv and check if the meter of the L3-3 follows in a linear fashion, ie readsout 100 too?
The procedure in the next chapter ‘Calibration of the frequency of tuning measurer.’ does work fine. In this test, tube 15 is inserted. On my L3-3, the signal in this setup is at it's maximum at 0.66 V AC and 1396 hz. (Nb for other readers: multimeters that also measure freq can be had for about 60 dollars on ebay).
I reduced the voltage to 0.45 AC as stated in the manual and kept the frequency at it's optimum of 1396 Hz. At these two settings, it is easy to calibrate the meter at 120 using the S calibration screw on top of the L3-3 – as one should expect. And I get sensible readings on tubes that are NOS (around 13 mA/V) or old used (as low as 3 mA/V on heavily used scope-pulled tube). But still, as the first calibration procedure above didn’t work, I’m not fully sure if the steepness of the tester is correctly calibrated.
The procedure in the next chapter ‘Calibration of the frequency of tuning measurer.’ does work fine. In this test, tube 15 is inserted. On my L3-3, the signal in this setup is at it's maximum at 0.66 V AC and 1396 hz. (Nb for other readers: multimeters that also measure freq can be had for about 60 dollars on ebay).
I reduced the voltage to 0.45 AC as stated in the manual and kept the frequency at it's optimum of 1396 Hz. At these two settings, it is easy to calibrate the meter at 120 using the S calibration screw on top of the L3-3 – as one should expect. And I get sensible readings on tubes that are NOS (around 13 mA/V) or old used (as low as 3 mA/V on heavily used scope-pulled tube). But still, as the first calibration procedure above didn’t work, I’m not fully sure if the steepness of the tester is correctly calibrated.
Essentially what you are doing in the first part of the ‘S’ calibration is to see if the frequency of the circuit is tuned within the proper frequency and that the 120mv input can be read on the test set meter prior to the final output. If this was not working properly, it would indicate a weak tube within the circuit.
To accomplish this check you will need the multi-meter and a signal generator.
I will try to explain the procedure this way. Remove the tube L15. You will need a signal generator (if you have access to one) to inject a 120mv AM modulated signal at the 1400Hz frequency into 6/I and the return of that signal to the ground terminal. The injected signal is what will defect the meter on the test set when the measurement button is pressed. Next you will adjust the signal generator frequency up or down to peak the test set meter with the measurement button pressed. That frequency should be 1400Hz +/- 50Hz. Write that frequency down. Then you will adjust the resistor to the right of the calibrate switch to 120(calibration mark). So what you are doing is making sure that if 120mv in = 120 on the test set meter. The next step is to change the amplitude of the input test set signal without changing the frequency to verify what is input to the test set is accurate to output. So if the signal generator amplitude is 100mv into the test set then the meter should read 100 on the test set.
Then complete the second ‘S’ check with the tube installed to the frequency that was written down and the 450mv.
I hope this answers you question.
To accomplish this check you will need the multi-meter and a signal generator.
I will try to explain the procedure this way. Remove the tube L15. You will need a signal generator (if you have access to one) to inject a 120mv AM modulated signal at the 1400Hz frequency into 6/I and the return of that signal to the ground terminal. The injected signal is what will defect the meter on the test set when the measurement button is pressed. Next you will adjust the signal generator frequency up or down to peak the test set meter with the measurement button pressed. That frequency should be 1400Hz +/- 50Hz. Write that frequency down. Then you will adjust the resistor to the right of the calibrate switch to 120(calibration mark). So what you are doing is making sure that if 120mv in = 120 on the test set meter. The next step is to change the amplitude of the input test set signal without changing the frequency to verify what is input to the test set is accurate to output. So if the signal generator amplitude is 100mv into the test set then the meter should read 100 on the test set.
Then complete the second ‘S’ check with the tube installed to the frequency that was written down and the 450mv.
I hope this answers you question.
Hello, I am new owner of a L3-3 and with your very useful guides I'll be hopefully able to calibrate the tester.
I have a BIG question though: where I can find a pin board layout with the correct numbering of each hole? Sorry if this sounds dumb, but I cannot find such information. The only thing I found it's a card with all holes punched, but the numbering seems incoherent with your indications (6/I etc.) Thanks for you help! Stefano
I have a BIG question though: where I can find a pin board layout with the correct numbering of each hole? Sorry if this sounds dumb, but I cannot find such information. The only thing I found it's a card with all holes punched, but the numbering seems incoherent with your indications (6/I etc.) Thanks for you help! Stefano
If the card you have has all the holes punched, then it is the calibration card or grid card. The upper half is I and the lower half is II and each half is numbered from 1 to 72. The first column is 1 thru 6 for the upper and lower. The second column is 7 thru 12 ans so on up to 72. See attachment
Attachments
Thanks for your help, it's really appreciated
. I see at last the meaning of "I" and "II" on the calibration card; they correspond in fact to the two sections (upper and lower) of the plastic pin board on the L3-3.I've bought a digital signal generator and will be hopefully able to perform the transconductance calibration very soon, as per your instructions posted here.
I'll keep you guys updated about this.
Best, S.
Do L1-3 and L3-3 share the same set of perforated card boards?
I have a set of cards for L1-3, but there seem to be some problems to use them with L3-3.
For penthodes like 6p14P even 6.3V filiament voltage is missing. But the same filament (6.3V) is supplied correctly for example for 6N5S/6N13S (6080), so its not a problem with power transformer. This could be of course problem with L3-3 itself, I replaced only burned resistors so far, but would like to clarify this issue anyway.
Thanks in advance for any suggestion(s).
I have a set of cards for L1-3, but there seem to be some problems to use them with L3-3.
For penthodes like 6p14P even 6.3V filiament voltage is missing. But the same filament (6.3V) is supplied correctly for example for 6N5S/6N13S (6080), so its not a problem with power transformer. This could be of course problem with L3-3 itself, I replaced only burned resistors so far, but would like to clarify this issue anyway.
Thanks in advance for any suggestion(s).
From what I understand, you should be able to use the same cards because the test set from L1 to L3 was just a component upgrade. I can’t be 100% certain since I do not have an L1. That being said, use the following link to view the L3 test cards and compare them to your L1 cards to see if they are the same.
http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Roe-Pruefer/L3-3/L3-3_Karten.pdf
Hi!
I have L1-3 and as far as I know they are practically the same - L1-3 and L3-3. Only with some minor changes outside, not on the schemes, etc.
L3-3 Cards and Spares
I have one of these, but I've not had the time to start using it. I did try the link above but no luck. Does anyone have cards for non-russian tubes ?
Also my 'push to test' switch has gone to heaven, does anyone know where spares can be obtained ?
Thanks in advance
I have one of these, but I've not had the time to start using it. I did try the link above but no luck. Does anyone have cards for non-russian tubes ?
Also my 'push to test' switch has gone to heaven, does anyone know where spares can be obtained ?
Thanks in advance