Tektronix TDS744A calibration on the cheap

A few tips I've found while preparing for, and finally calibrating a TDS 744A oscilloscope. If you don't have time to watch, here are the main takeways:
- Supported ISA GPIB cards : www.eevblog.co...
- CVR calibration does NOT absolutely require a metrology-grade DC calibrator
- CVR calibration needs +- 9.5V at the highest setting (not 104V as the service manual indicates) ; look at your "CVRCAL.500" file to confirm
- HF cal needs 505MHz for a 500MHz scope, at +16 to +17 dBm. Most signal generators cannot do this, but a simple RF amplifier will do the trick.
- HF cal : watch out for lossy coax cable (e.g. RG58 ) ! Even 0.6dB of loss will cause problems. Manual compensation is OK.
Segments:
00:27 3 objectives
01:51 DOS machine
03:21 CVR requirements (DC calibrator)
05:48 DIY DC calibrator
08:35 HF requirements (signal generator + amp)
10:36 first HF cal failure
13:21 second HF cal failure
16:01 interleave cal, easy
17:43 lossy coax cable !
19:10 trigger cal, easy
20:20 HF cal success !

[@keithnoneya]

Yep I haven't done a calibration on this scope, however I did run into the problem with Cable Loss at different frequencies when calibrating other test equipment. In my early years of working on radio's I learned a valuable lesson when using the wrong RG Cable and coiling them if they were too long. Basically use the right RG cable for your frequency and power, compensate for cable loss and don't coil them to save space on the bench, it will mess up your adjustments every time. Been there done that! Would like to see some videos just on the setting up the software etc and all the stuff related with that. Thanks for sharing loved the video. Best Wishes & Blessings. Keith Noneya

[@visitslovenija]

I have to say, I think your video deserves to be better known. There are guys on the Tek forums who , for sure, would say it’s not possible to do what you achieved here. So good work.
And I too wish I still had that old DOS computer!

[@fenugrec5697]

Thanks ! I think I posted a link to this video on both the Tek forums as well as EEVBLOG but received very little interest or feedback...