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Old 23rd Dec 2019, 11:27 pm   #105
MotorBikeLes
Nonode
 
Join Date: Dec 2012
Location: Kirk Michael, Isle of Man
Posts: 2,346
Default Re: Telequipment D75 scope.

I just went to look at the numbers on mine. V unit is E543052, so earlier than both yours (unsurprisingly). The "H" unit however: No "normal" TQ label. Instead a paper label with "Serial No. TG1172". Does TG mean testing group, or somebody's signiature? -- I have a few internal circulation documents, if i get time I will look for those initials. The 1172 obviously suggests Nov '72. The TEKWIKI photo (Your P I now see) has PC155 as the H board. My board is totally different. It is a convenient board (I don't recognise it) that has been used as a placeholder for the few components. It looks like the board for a differential Y amp (preamp), but I may show a photo of it later.
I MAY complete both the circuits, with some errors spotted by Mark corrected, and my "made up" component numbers replaced by those on your amp.
Mark, I have thought about calibration. Since these were intended for D(M)63, D75 and D83, they need only to be "OK" for something above 50MHz.
I have a Tek 475, so maybe could monitor the output (at 50 ohms??) whilst powering the rails from a D63 mainframe. Then it could perhaps be optimised for a good spare input pulse. Maybe my C3 calibrator would be good enough.
Just thinking aloud.
les.
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