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I have been looking for other fans of vintage tektronix stuff for
ages! I have an old 545b unit with ca dual trace plug in module, but
I have a few problems with it & have not been able to find a service
manual.

I am a sound engineer from the U.K & no one seems to know much about
old tek gear (including tektronix U.K)! So if any of you guys could
lead me to any technical data or service manuals, it would be most
helpful.

I checked out the SND tube sales site the other day & discovered that
Tektronix used to make a valve curve tracer (the 570). I do quite a
lot of work on old valve equipment, (usually fixing guitar amps for
friends) & it would be great to test the valves I have to see how
well they match. Many amps that come in have an assortment of valves
where one has been replaced when it has finally expired instead of a
new matched set being fitted.

Thanks to stefan for the T & M museum, theres some useful &
interesting stuff in there, & I enjoyed looking through the exhibits.

Bye for now, I shall log on again soon!

In a message dated 11/1/00 5:52:38 PM Eastern Standard Time, sjhel@...
writes:

I checked out the SND tube sales site the other day & discovered that
Tektronix used to make a valve curve tracer (the 570). I do quite a
lot of work on old valve equipment, (usually fixing guitar amps for
friends) & it would be great to test the valves I have to see how
well they match. Many amps that come in have an assortment of valves
where one has been replaced when it has finally expired instead of a
new matched set being fitted.

The 570 is a very rare item even here in the US. A friend of mine had one and
sold it to a collector for a quite high price. You can see that very unit on
the cover of Alan Douglas's "Tube Testers and Classic Electronic Test Gear".
According to the book, only about 1000 were made over a period of ten years,
starting in 1956.

Mike Csontos

Hello Stuart,

Welcome to this group of Tek scope fans!

The type 570 Tube Curver Tracer is probably the most desired of early Tek
scopes. This also makes is rare and expensive. Tek only made about a
thousand of them and most of the remaining ones are in the hands of "glass
audio" enthusiests who value them very highly. Pristine ones are worth
about $3000 USD in the Far East, as I understand it. You would be very
lucky to find one at any price . . . I have one in my collection, but I was
lucky to find it in an estate sale in a barn about 30 miles from my home
near the orignal Tek plant. Mine is a proto-type and was built before
regular production on them started. I got it for $40 USD, as I recall it.

You might find the web page dedicated to early Tek scopes at
<> to be of interest to you. There is a list of
people who can supply manuals or copies of manuals there for Tek
instruments. I sell some manuals myself on eBay so you might want to check
that out too.

I have a rather huge collection of old Tek stuff (665 instruments) and I
might be able to help you solve some of your 545B/CA problems if you
describe them to me. You will need manuals for each of those instruments
and it would help if you had them first so we can have a common ground for
discussing the circuitry.

Stan
w7ni@...

Stuart Hellier wrote:

Hi stan, thanks for the website info. Stefan has kindly offered to photocopy
his 545b manual so that's one hurdle crossed.
The problems i'm having with my 545b are:

The trace stops and becomes a stationary dot once the scope has been on for
around 10-15 minutes.

Channel A of the CA plug in does not match the voltage settings of CH B even
when adjusting the gain pot.

Horizontal display selections other than B and B intensified by A only
display a dull "cloudy" hue, occasionally showing a trace as you turn the
time / cm control.

I have a tube tester & tested all tubes for quality and leakage & they all
checked out okay so I guess these problems are to do with other parts of the
circuitry.

Bye for now

Stuart

sjhel@... wrote:

Hi stan, thanks for the website info. Stefan has kindly offered to photocopy
his 545b manual so that's one hurdle crossed.
The problems i'm having with my 545b are:

The trace stops and becomes a stationary dot once the scope has been on for
around 10-15 minutes.

Most scope problems, it seems, are in the power supplies. I would check the
power supplies to make sure they are still regulating when the problem shows up.
It would be helpful to know if both A and B sweeps stop at the same time or if it
is just one of them.

Channel A of the CA plug in does not match the voltage settings of CH B even
when adjusting the gain pot.

On this problem, I would like to know if it appears that the gain is too low or
too high and which channel seems to have the problem? Is the same problem
evident in all setting of the volts/div switch or is it just one position?

Horizontal display selections other than B and B intensified by A only
display a dull "cloudy" hue, occasionally showing a trace as you turn the
time / cm control.

Since the trace seems to be there only occasionally, it sounds related to the
first problem you mentioned.

The dull "cloudy" hue may be due to faceplate clouding on the CRT. Take a close
look at the pads cushioning the CRT inside of the shield at the faceplate. Are
these BLACK foam rubber or are they sort of orange-brown in color? If it is a
strip of black foam-like material, this is bad news and needs to be replaced with
different cushion material. There was a chemical reaction between the material
that bonds the plastic implosion shield to the front of the CRT and the black
cushion material that results in the bonding material in front of the CRT turning
cloudy. There is a cure for this and I can share more information with you about
it if the cushion materials are black or you thing the CRT faceplate bonding
material has become cloudy.

I have a tube tester & tested all tubes for quality and leakage & they all
checked out okay so I guess these problems are to do with other parts of the
circuitry.

Bye for now

Stuart

OK Stuart, we are started now and the 545B is certainly worth the trouble to
fix.

Stan
w7ni@...