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Tektronix 465 scope issues

Discussion in 'Troubleshooting and Repair' started by bktheking, Sep 14, 2012.

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  1. bktheking


    Sep 14, 2012
    Hey all, new to the board and looking for some help with a sick 465.

    Initially the -8v feed wasn't working, I had no spot checker/trace. I replaced the diode bridge and IC and presto- I now have a trace. Issue is the trace wouldn't center. I went back to voltage checking and discovered my 15 v was actually reading 14.1 so I went about finding the issue, open resistor. Replaced and now sitting at 15V with a trace far off the screen. If I short the two test points 322 and 324 together the line appears in the center of the display. According to the block flow chart it's an imbalance in the "vertical switching circuit". It does this in both channel 1 and 2. Q322 and 324 are the last transistors connected to the delay line. If I press the trigger button the waveform on line test appears but cannot be moved, don't know if that's the way it's supposed to be. At a base voltage reading of -1.2 and emitter reading of -.2.0V i get 0.700v, the diagram shows it should be zero (0) volts. Is this what it's supposed to be?
  2. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    Nov 28, 2011
    It might be helpful if you posted a schematic with measured voltages marked (set the position controls to mid-position).
  3. bktheking


    Sep 14, 2012
    Got it working last night, r326 was open causing one collector voltage to go negative.
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