Yes, but in actuality, you can very often pick up a good 465 or 475 for
$100 or so, take it home, clean it up, and it will work for you for
years. That's hard to beat. 73 de Alex NS6Y.
On Jan 23, 2006, at 8:36 PM, Don Brown wrote:
Hi
Be careful buying older Tek scopes. Many of the repair parts are not
available any more. You may get lucky and never need to repair one of
these
scopes but many of the parts were proprietary made custom for Tek or
in the
case of some of the IC's and CRT's were made only by Tek in there own
fab. I
worked for Tektronix for many years as a field maintenance instructor
in the
test and measurement division. My specialty was the 7000 series and the
portable scopes among others. The reason the 7000 series is so cheap
on Ebay
is the problem of getting repair parts. The most common problem is
with the
cam switches and attenuators in both the 7000 and the 465 and 475
scopes.
The 485 is even a generation earlier than the 465 or 475 so I would
not ever
consider one these scopes unless it had a good CRT, is in excellent
condition and was virtually free. It also takes a real expert and some
special equipment to properly tweak a 485 so it will meet specs. The
7000
series may be OK if you can buy two for a few hundred dollars. The
second
one for parts. I have a friend with a cal lab that has a warehouse
full of
broken 7000's that he uses for parts to keep the stuff he has under
contract. Tek has a policy that they do not guarantee parts support
seven
years after a product is discontinued. The 465, 475 and most of the
7000 has
exceeded that by two and the 485 by three
However I personally own a 2465 and can highly recommend it. It is 400
Mhz
four channel with both 1 meg ohm and 50 ohm inputs with dual timebase.
This
was the last of the really great analog scopes Tek made. This scope
sold for
over $5000 in the mid 80's and was worth every penny. I have seen them
on
Ebay for well under $1000 (I paid $800 for mine a couple of years ago)
I
know that is a lot of money to spend on a scope used for hobby work
but a
new scope with much less capability will cost as much or more.
Ron Is correct on the bandwidth specification. Scopes are rated at 3
db down
at the rated bandwidth. This means a 100 MHz scope can measure a one
volt pk
to pk 100 MHz sine wave at .707 volts and still be in spec. Also the
probes
are rated at a max bandwidth as well. If you use a 100 MHz probe on a
200
MHz scope then you will only have a 100 Mhz bandwidth at best
Don Brown
KD5NDB
----- Original Message -----
From: "Alexandra Carter" <[EMAIL PROTECTED]>
To: "Ron D'Eau Claire" <[EMAIL PROTECTED]>
Cc: <elecraft@mailman.qth.net>
Sent: Monday, January 23, 2006 9:13 PM
Subject: Re: [Elecraft] Oscilloscopes (WAS: spectrogram)
Tektronix 475, baby! The 465 is OK, and the 485 a real 400MHz work of
analog scope art I hope to own someday. Then if you're really serious
you have a 7000-series mainframe and a lot of plugins hehe.
A really good tutorial on scopes is Tektronix's The XYZ's Of Using A
Scope which they used to give out, now you can download it from the
net
and the recent versions have a bunch of stupid stuff about their
digital scopes - they tell such beautiful lies, stick to analog.
73 de Alex NS6Y.
On Jan 23, 2006, at 7:06 PM, Ron D'Eau Claire wrote:
Jim, AB4CZ gave you an excellent summary.
If you think you'd like to use the 'scope for general bench work to
look at
waveforms, etc., on HF gear, then look for one with at least a 200
MHz
bandwidth. ...........If you try to observe signals on a narrower
bandwidth oscilloscope, the
higher-frequency information is simply lost.....
At today's Hamfest prices, the price difference between a basic
waveform
monitor and a good general purpose scope is often small....,
Ron AC7AC
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