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Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders. |
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Thread Tools |
30th Oct 2020, 11:52 pm | #21 |
Pentode
Join Date: Jun 2019
Location: Dortmund, Germany
Posts: 161
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Re: Bradley oscilloscope calibrator type 192 restoration
Thank you for taking the scan. I too have a manual of that version. It came with the scope. However, it is not an original but an incredibly bad copy or printout so that this page is nearly completely unreadable.
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31st Oct 2020, 11:36 pm | #22 |
Octode
Join Date: Jan 2007
Location: Dorridge, West Midlands, UK.
Posts: 1,486
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Re: Bradley oscilloscope calibrator type 192 restoration
Pinorkel, PM me your email address and I can send you a clean scan.
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Chris Wood BVWS Member |
24th Feb 2021, 9:46 pm | #23 |
Pentode
Join Date: Jun 2019
Location: Dortmund, Germany
Posts: 161
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Re: Bradley oscilloscope calibrator type 192 restoration
Last weekend, I tested the outputs of the 192 with my new 6.5 digit multimeter and nearly all outputs seem to be in spec. Only the voltage calibrator is slightly out of spec for some values. To me, it looks like some of the resistors in my rebuild attenuator may have drifted, or my new design has some negative side effects.
To do further checks, I looked into the calibration instructions for the voltage calibrator. At the beginning, Section 5.11.3 states that the resistance between the inner and outer part of the respective BNC socket must be 220 Ohms at the 10 mV setting. After having measured 225 Ohms, I looked into the diagram of the old and my new attenuator and both diagrams agreed, that the measured value is the correct one and not the 220 Ohms stated in the calibration instructions. So I was wondering if anybody here has tried to calibrate the voltage section according to the manual and succeeded. For a precision instrument, the manual seems to contain a lot of errors. Apart from this one, I already found three errors in the circuit diagrams. |