Re: Tek 465B with less than good focus


Denis Cobley <denis.cobley@...>
 

Hi George
These are getting old (like all of us).
The CRT's lose sharpness with age - my best suggestion is to get a 2200 CRT
(154-0861-00) from any 2213A, 2215A, 2220, 2221/A 2230, 2232, 2235/A 2236.
These CRT's were much sharper new and will always give better results.
You can buy a dead / damaged unit on ebay very cheap.
Pull the CRT, remove the trace rotation coil and it's a perfect fit (gains
and timing will be very close).
This CRT can then be you test tube - swap it into each scope - if the trace
is still bad you have a fault - if it comes good then your old CRT is beyond
it's useful life.
Regards
Denis
Regards
Denis Cobley
Newtek Support Pty Ltd
11 Lyon Park Rd
North Ryde 2113
Australia
Ph 61 2 9888 0162
Fax 61 2 9888 0125
www.newteksupport.com

----- Original Message -----
From: "George Headley" <georgeheadley@mybluelight.com>
To: <TekScopes@yahoogroups.com>
Sent: Friday, November 21, 2003 12:46 PM
Subject: [TekScopes] Tek 465B with less than good focus


Hello Group: This is my first post but I feel that I know all of the
regulars. I'm very impressed with your knowledge and have learned a lot from
your experiences. I an an old computer tech , retired but not ready to give
up the challenges relating to Tektronix scopes. I have been buying them
mostly for the challenges found in the repairs but somewhat out of respect
for equipment that is fun to work on because of the quality. I have several
465B that have poor focus. Not really bad but not good enough. There is some
improvement when I limit to 20MHz. I dont have a HV probe but I suspect HV
problems. I know from experience that low HV will cause a blooming of the
trace. I have adjusted the CRT bias as per the manual. Slight improvement,
astig and sweep ckts within spec. If I can trouble you for a minute of your
time do you have any suggestions. one more thing , it may be my imagination
but the rise and fall lines seem to be sharper than the time base lines..
George Headley

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