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Tek 465B: Display Problem (Shrinked to 3 divisions)


shiran@...
 

Hi, I am a student and I got my Tek 465B from an eBay auction. I know
how to use the oscilloscopes, but have no experience in idendifying
and fixing problems in oscilloscopes.
The problem is that, the trace or a signal width is limited to maximum
3 divisions on the time scale (i.e. when the Horizontal Position knob
is fully turned to left). Turning the Horizontal Position knob to
right will reduce the width to 1 division on the time scale. I cannot
get this to occupy the full with (10 divisions) on the screen. Is
there a screwdriver adjustment knob somewhere to fix this or is this
an internal problem? (Also I notice the trace travels from right to
left, Is this normal?). Apprciate if someone can help me to identify
the problem. Thanks - Shiran.


Stan or Patricia Griffiths <w7ni@...>
 

Hi Shiran,

No, the trace traveling from right to left is not normal.

The first suggestion that I have is for you to take off the cabinet and take
a look at the CRT neck pins, about halfway from the front to the rear of the
scope. The two coming out of the right side of the CRT shield are supposed
to go to the horizontal amplifier. One of them may be disconnected and/or
the connectors may be connected to the WRONG pins. It may say right on the
CRT shield which color of wire should go to which pin. If those wires seem
to be connected properly, then I suspect a problem in the horizontal
amplifier, but . . . you always need to start by checking the power supplies
first. You will need a service manual to check the power supplies since it
will tell you where the test points are and what readings to expect there..
Do you have one? If not, get one . . . then we can go from there.

Stan
w7ni@easystreet.com

shiran@paradise.net.nz wrote:

Hi, I am a student and I got my Tek 465B from an eBay auction. I know
how to use the oscilloscopes, but have no experience in idendifying
and fixing problems in oscilloscopes.
The problem is that, the trace or a signal width is limited to maximum
3 divisions on the time scale (i.e. when the Horizontal Position knob
is fully turned to left). Turning the Horizontal Position knob to
right will reduce the width to 1 division on the time scale. I cannot
get this to occupy the full with (10 divisions) on the screen. Is
there a screwdriver adjustment knob somewhere to fix this or is this
an internal problem? (Also I notice the trace travels from right to
left, Is this normal?). Apprciate if someone can help me to identify
the problem. Thanks - Shiran.

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