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Heathkit IO4560 scope

This scope is on the very low end of the scale of sophistication. The Heathkit brand suggests it must have been a kit. It has been built around 1975, judging by the manufacturing codes on the TTL chips in the time base.

IO4560 inside

Inside the IO4560, sideways view facing the power transformer.

This is a very simple design. The time base has only 2 ranges, "high" and "low", and you set the horizontal speed with a potmeter that has a range of about 100:1. There is no magnetic shield round the CRT, which gives hilarious results when you want to adjust something and use a slightly magnetized screwdriver by accident. Even fairly weak remanent magnetism on a screwdriver makes the spot move several cm on the screen.

I bought it on the flea market on Queen's day in 1988. When I picked it up, I first thought the case was empty because it weighed almost nothing. But it cost only ƒ25, so I thought this could not be a such a bad deal.

IO4560 inside

A look from above, showing the timebase circuit board.

As you can see on the photographs, it contains mostly air. The power transformer has a metal shield, presumably to shield the magnetic field, and maybe to prevent casualties by electrocution. Actually, there are two power transformers in the shielding case. The power supply components are below the frame plate. There is no HV regulation so the image moves all over the place when you move any setting. The time base is built on a PCB. The horizontal and vertical amplifiers have been built on phenolic strips.

Although it did work, it recently stopped working after I had been experimenting a bit with it. The spot seemed to be stuck to the right. It turned out that an electrolytic in the low voltage supply for the time-base and the pre-amplifiers had come loose. Sloppy soldering work. After fixing that it worked again.

Copyright © 2000, 2001 by Onno's E-page         published 2000-08-13, last updated 2001-10-28