For sale in UK: 549 with 1A4 plugin


Hi Tek fans,

Due to lack of space, I reluctantly have to part with my 549 and its 1A4
plugin. I restored it to clean working order a couple of years ago and it's
still in excellent shape.

You can read the full restoration story starting here:

And there are lots of nice photos here:
and even a movie here:

The Tektronix 549 is the only storage scope in the Tektronix 500 series of
plug-in scopes. It dates from the late 1960s, and uses an analogue storage
tube. It's bistable rather than variable-persistence, and has the
enormously cool feature that storage mode can be used separately in the
upper and lower halves of the screen.

It's a big, heavy, power-hungry monster. It weighs 65lbs (30kg) or so and
draws more than 500W from the mains. I wouldn't say it's a practical
everyday scope, and it's definitely not for beginners. The brightness from
the storage tube is low (it's best used in a darkened room) and getting the
best results from it needs patience. Using it is like playing a musical
instrument. It has all the usual Tek trimmings: dual timebases, multi-level
calibrator, and connections for every imaginable accessory. Its bandwidth
is about 30MHz but sadly it doesn't have tunnel diode triggering so really
fast stuff is a bit of a chore.

This example of the 549 comes with the elusive 1A4 plugin. This plugin has
four fully-featured channels, and allows dozens of combinations of
chopping/alternating between them. You can freely choose the trigger source
from any of the four channels. I know this plugin is particularly sought
after, and this one is in good working condition on all four channels,
albeit a bit drifty until it's warmed up.

There are not many of these scopes around in this condition. It even has
the correct rectangular CRT bezel. This particular one, being built in
Guernsey, doesn't have the 'Bumble Bee' paper capacitor problem that
plagues US-built examples. It's also had a replacement hand-made EHT
transformer which doesn't suffer from the lossy epoxy problem that the
original transformer had.

Calibrated? No, not formally, but I've adjusted everything to within spec
as best I can. I'd be surprised if anything was more than a few percent
wrong. And the icing on the cake: I've got the printed paper manuals for it
and the plugin. They themselves are works of art.

The price for this slice of technology history? I'm asking £120, including
the plugin and manuals. Come and get it from Cambridge, UK. I will be
driving across Europe in a couple of weeks time, so may even be able to
deliver to somewhere between Cambridge and Warsaw.


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