Tektronix 2465A Oscilloscope Repair - Part 5

 

Tektronix 2465A Oscilloscope Repair - Part 5

CAL 01 – Horizontal

CAL01.PDF

Now that the basic power supply and CRT display are set up, we can continue with the meat of the calibration. It is suggested that all of the CAL xx steps be run in order, in the same session.  I tried to split it up, and it seemed to not store my results between sessions (even with my new lithium battery).  When I ran them all in the same session, the calibration factors were all stored and remain through power cycles now.

First, you must put the CAL ON/OFF jumper into the CAL ON position.  This is on the A5 Controller board.

 
CAL Jumper

Step 1 – Horizontal Timing, X1 Gain, X10 Gain, Center, Transient Response

Following the detailed instructions 1a – 1c will put you into the CAL 01 function.

 
1b – Begin Calibration

 

 
1c – CAL 01

Steps 1d – 1g connects the scope probe to an internal test point on the scope (R489).

 
R489 Location

 
R489 Test Point

 
CAL 01 – f

 
CAL 01 – g

Then you use the delta-ref and the delta controls on the front panel to center and join the two traces presented (1h).

 
CAL 01 – h

Steps 1i – 1k sets us up for the next test.

Steps l and m set us up with our marker generator to begin calibrating the horizontal timing. I used my function generator to send relatively narrow pulses at the rates specified in the manual. This is probably not as good as the real marker generator called for, but I think it will get me by for amateur purposes.

 
CAL 01-l

Steps m and n appear to be setting up a baseline timing for the rest of the tests, but I can’t be sure. You get two pulses on the “B” trace, and use the Delta Ref and Delta controls to highlight the sixth time marker, and to overlap them to make them look like one.

 
CAL 01-n

 
CAL 01-o

Continued next post…

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