For accurate calibration you have to pass 50 microamps through the meter and set the needle deflection to full scale using R2. You then measure the resistance between the input to the meter (left side of R2) and the far side (right side) of R1 and adjust R1 until you have 5k ohms exactly. That is DC and Ohms calibration done. Then you can test accuracy on all ranges for full scale deflection using a reference DC source. If there is any inaccuracies the prescaling resistors need to be checked. Once that is done you can calibrate AC volts using a known AC voltage for full scale. Once again the prescaling resistors values will affect meter accuracy.
Thx very much for explanation en guidance. Recently, I got one (IBM version) and very happy with it as it brings me back to the times of good history. It came with a DB (decibell) adapter which could plugged in on top using the 0.6mA scale.
Good question. I was going to check then I realized I would have to take it all apart to find your answer. I would start with standard imperial size allen keys then try metric keys. Beyond that, I supposed they could have used "Bristol" wrenches since this is branded an IBM product. IBM was really into Bristol wrenches because they were used a lot in their typewriter line.
Hello- thanks for the video. I ordered a new cover for my meter and it did not have the anti static coating. Can you recommend a spray for this problem? - Phil
I have heard that a 50/50 percent solution of Downy Fabric Softener and water sprayed on the inside of the meter face may eliminate the static buildup issue.
Hello how much is a good price for a working Simpson 160 with the original case and manual in great condition? Just wondering so I don't over pay as I'm looking to pick one up. Thanks for the video and your time!
For accurate calibration you have to pass 50 microamps through the meter and set the needle deflection to full scale using R2. You then measure the resistance between the input to the meter (left side of R2) and the far side (right side) of R1 and adjust R1 until you have 5k ohms exactly. That is DC and Ohms calibration done. Then you can test accuracy on all ranges for full scale deflection using a reference DC source. If there is any inaccuracies the prescaling resistors need to be checked. Once that is done you can calibrate AC volts using a known AC voltage for full scale. Once again the prescaling resistors values will affect meter accuracy.
Thanks Derek, glad your post is here for future reference. Those instructions I got were very confusing, yours are much better!
Thx very much for explanation en guidance. Recently, I got one (IBM version) and very happy with it as it brings me back to the times of good history. It came with a DB (decibell) adapter which could plugged in on top using the 0.6mA scale.
Right, I have my Db adapter around here somewhere as well. Probably still in my old service case.
Hello, Great video! I was wondering whether you know the size of the Allen Wrench I need to use to remove the selector knob screw?
Good question. I was going to check then I realized I would have to take it all apart to find your answer. I would start with standard imperial size allen keys then try metric keys. Beyond that, I supposed they could have used "Bristol" wrenches since this is branded an IBM product. IBM was really into Bristol wrenches because they were used a lot in their typewriter line.
Hello- thanks for the video. I ordered a new cover for my meter and it did not have the anti static coating. Can you recommend a spray for this problem? - Phil
I have heard that a 50/50 percent solution of Downy Fabric Softener and water sprayed on the inside of the meter face may eliminate the static buildup issue.
Hello how much is a good price for a working Simpson 160 with the original case and manual in great condition? Just wondering so I don't over pay as I'm looking to pick one up. Thanks for the video and your time!
Ya know I'm not really sure. I personally wouldn't give over $30 US for it.