On 26/01/11 18:29, V G wrote:
> Price: cheap as possible.
> Size: small is preferable, but not essential.
> Feautres: doesn't need to be fancy, or high bandwidth. Just something "go=
od
> enough".

Look for a Tektronix 400 or 2400 series scope.

The 2400s are more modern machines and much more expensive. Plus side is=20
that you get things like GPIB control, frequency counters and on-screen=20
display, but they're harder to fix when they do eventually break. And=20
break they will -- one of the display hybrids (U600?) is renowned for=20
burning itself out. They're no longer available, and if it fails, your=20
scope is a write-off.

The 454 was the old field-service standby. Built like a tank, weighs a=20
fair amount, but almost indestructable. Most of the parts (not counting=20
CRT, power supply module and HV multiplier, and maybe the horiz/vertical=20
hybrids if it has them) are standard. Those parts which aren't standard=20
are easily obtainable (Sphere have plenty of stock, as does Deane Kidd,=20
a former Tek engineer).

There's also the 465 -- can't remember what was different between this=20
and the 454.

I personally have a 466 -- this is a 100MHz analog storage scope. Note I=20
said *analog* storage: it writes on the CRT display, then 'holds' the=20
image. Catch is that you have a limited storage time (a few minutes=20
usually) after which the image fades out, and getting the settings right=20
is a bit of a faff. It's still better than a non-storage scope, and in=20
some cases can be better than a DSO: bear in mind that you're storing=20
*exactly* what's been captured, not a quantised numerical representation=20
of it.

Expect to pay about $150 for a 465 in good working order, fully tested=20
and in good physical condition. 466es are a bit harder to find, expect=20
about $200 to $250. You can sometimes get good deals on ex-rack gear:=20
testgear which has been mounted in a 19in rack, but where the parts to=20
convert it back to standalone use (mainly the desk feet) have been lost.=20
These can be a good deal if you can get the scope to eye level (read:=20
bookshelf or tabletop storage system of some description), but you won't=20
have the tilting front handle you get on the base units. Also expect=20
them to have been used more heavily than a bench scope: they'll=20
typically have been used in e.g. transmitting stations for monitoring=20
the modulators and transmitters. In these situations, they're generally=20
left switched on...

--=20
Phil.
piclist@philpem.me.uk
http://www.philpem.me.uk/
--=20
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