> A few years ago I picked up a 1970s vintage Sperry Mk-8 Radar indicator unit > with the intention of making a scope clock. It's finally getting some bench > time and before starting on a long and painful reverse engineering effort I > was wondering whether anyone might have some data or schematics about it. It > will be an interesting challenge - I've never done anything with a > magnetically deflected CRT before.
Those are interesting. Many radar units have a fairly low frequency sweep, which can make it tricky to use them as scope clocks. If you end up having to replace the deflection amplifiers, look at the schematics of vector monitors: the trick is to use op-amps driving power transistors to switch plenty of voltage to the yokes, with current feedback from sense resistors. The op-amps will then drive up the voltage to drag the current around through the inductance of the yokes. If the yokes won't behave, you'll either need more voltage or new or rewound lower inductance yokes. Small ones (like the Vectrex) drove the yokes directly with power op-amps like the LM379. I'm working on a similar lashup myself, in order to use common magnetically-deflected CRTs. When I was a teenager, I'd modify TVs like Greg mentioned, pulling the original yoke off the CRT (but leaving it in circuit, so the high voltage is available), adding a second yoke and audio amplifier, and using them to display big lissajous figures. I made several of them for friends. I had plans to try driving colour CRTs with bandpass filters for a "colour organ" effect, but never got around to it. - John -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/30EE3C45-CD98-4796-BA0F-5B9A9BDB6BC8%40mac.com. For more options, visit https://groups.google.com/d/optout.
