Re: Hello everyone @ tekscopes


Stan or Patricia Griffiths <w7ni@...>
 

sjhel@aol.com 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@teleport.com

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