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TonyDuell · 20th Apr 2021, 3:53 pm

Some of these large-screen XY displays were used to display vector graphics (where a computer moves the beam around with a couple of DACs rather than having the beam scan a raster and turning it on at the appropriate times).

My limited-ish experience is that DEC and Tektronix XY displays were magnetically-deflected, whereas the HP ones were electrostatic. The latter certainly means a special CRT which is impossible to find as a spare part.

Some of the Tektronix ones used storage CRTs with all the fun that involves.

The little DEC one I have (VR14) uses a normal CRT but the EHT generator is a can (probably oil-filled) containing a mains transformer and voltage doubler circuit. A circuit diagram is printed on the can. I suspect the output of that, like most mains-produced EHT supplies, is lethal. The HP and Tektronix diplays use a more friendly high-frequency transforner supply.

The HP1311 shown earlier is missing the stand. This supports the unit from a pivot shaft on each side so you can tilt it. Said shafts line up with the center of mass of the unit of course. The top and bottom plastic covers come off the chassis very easily, there then plug-in PCBs for most of the functions and there's an extender board inside the unit. Look out for the cartoon of the electrocuted cat on the EHT circuit in the service manual (!)

One unit to drive the HP1311 is the HP1350 'graphics translator'. This takes in a subset of HPGL over an HPIB interface and displays it as vectors on the HP1311 screen. What makes it odd is that it's all random logic. A microcoded design would, I think, have been a lot simpler.

Tektronix made an 8-channel multiplexer and timebase unit to use their XY displays as a low-bandwidth 'scope. I can't remember the model number, something like 4701? I can dig out the manual if anyone is interested.

20th Apr 2021, 3:53 pm	#18
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,225	Re: Large Screen Oscilloscopes Some of these large-screen XY displays were used to display vector graphics (where a computer moves the beam around with a couple of DACs rather than having the beam scan a raster and turning it on at the appropriate times). My limited-ish experience is that DEC and Tektronix XY displays were magnetically-deflected, whereas the HP ones were electrostatic. The latter certainly means a special CRT which is impossible to find as a spare part. Some of the Tektronix ones used storage CRTs with all the fun that involves. The little DEC one I have (VR14) uses a normal CRT but the EHT generator is a can (probably oil-filled) containing a mains transformer and voltage doubler circuit. A circuit diagram is printed on the can. I suspect the output of that, like most mains-produced EHT supplies, is lethal. The HP and Tektronix diplays use a more friendly high-frequency transforner supply. The HP1311 shown earlier is missing the stand. This supports the unit from a pivot shaft on each side so you can tilt it. Said shafts line up with the center of mass of the unit of course. The top and bottom plastic covers come off the chassis very easily, there then plug-in PCBs for most of the functions and there's an extender board inside the unit. Look out for the cartoon of the electrocuted cat on the EHT circuit in the service manual (!) One unit to drive the HP1311 is the HP1350 'graphics translator'. This takes in a subset of HPGL over an HPIB interface and displays it as vectors on the HP1311 screen. What makes it odd is that it's all random logic. A microcoded design would, I think, have been a lot simpler. Tektronix made an 8-channel multiplexer and timebase unit to use their XY displays as a low-bandwidth 'scope. I can't remember the model number, something like 4701? I can dig out the manual if anyone is interested.