Quote:
Originally Posted by MrBungle
They are mostly empty AFAIK. The horizontal cal had a BC109 and pretty much naff all else in it than a bit of coax to a front panel BNC
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The Y unit is a bit more involved, with a dual transistor and a pair of 2N2369s. There's a preset resistor and a pair of pre-set trimmers. As Les says, how do you calibrate these?
As the main point of the Y unit is to setup the HF adjustments in the main-frame Y amps, it is essential the calibrator is right. Having used the calibrator to then get the Y-amps right, you then adjust all your Y modules for best HF performance. If the Y-amps are not right, then you're in a rabbit hole with that one (been there, got the t-shirt).
If people wanted to build their own, it won't be enough to reverse-engineer the circuit (which I've done - it's not difficult), because they'd have to dream up some sort of routine to calibrate the adjustments on the calibrator. I'm sure it's doable - it might be as simple as building a test jig that resistively loads the output of the calibrator and adjusting for best square wave response - but it would involve quite a bit of effort of the part of someone like Les or myself who actually own them. It's on my to-do list, but so is everything else.
When I eventually get around to it, I'll add the details to the Telequipment secion of my website.