Tek 2213a focus

[Steve Bailey]

I have a Tektronix 2213a with a fuzzy trace. Adjusting with the focus
knob does not correct the problem. Can this be fixed or adjusted from
within the scope and if yes, can you give me the procedure?

Thanks,

Steve

[Jerry Greenberg]

Steve Bailey wrote:

On the inside of the scope, most of the time in the power supply section
there is an adjustment called Astig, or Astigmatism. This is for the
roundness of the beam. Some models have the astig on the rear of the
scope, either on the outside rear, or on the inside.

I use a detailed wave pattern on the screen, like a lot of sinewaves
crushed together. I then adjust the astig and focus together for the
best sharpness.

One service manual sais to do this on a square wave, and adjust for the
vertical and horizontal being the best ballance of sharpness using both
the focus and astig adjustments.

If this doesn't bring in the adjustment, then there is a supply problem,
or the CRT is getting a bit weak...

--

Jerry Greenberg GLG Technologies GLG
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[Kevin Carney]

Do a newsgroup search, you will find a string of resistors
that have changed value. About 5 or 6 of them brown up and
change value. They are under the CRT near the rear / mid
section of the scope. Take Care

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"We ought always to know precisely why a given job
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[Jim Yanik]

carn...@us.ibm.combo (Kevin Carney) wrote in
<3B001EB2...@us.ibm.combo>:

>Do a newsgroup search, you will find a string of resistors
>that have changed value. About 5 or 6 of them brown up and
>change value. They are under the CRT near the rear / mid
>section of the scope. Take Care
>
>Steve Bailey wrote:
>>
>> I have a Tektronix 2213a with a fuzzy trace. Adjusting with the focus
>> knob does not correct the problem. Can this be fixed or adjusted from
>> within the scope and if yes, can you give me the procedure?
>>
>> Thanks,
>>
>> Steve
>

They're either 510K or 1 M ohms,0.5W,carbon film type resistors,located
around the focus pot on the main board.I advise changing them all at the
same time.The best replacement is with carbon COMPOSITION types,same value
and wattage.
--
Jim Yanik,NRA member
remove X to contact me

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