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Canceled Heathkit IO 4540 5 MHZ Triggered Oscilloscope

Discussion in 'Ham Radio Gear For Sale' started by W2GAH, Nov 29, 2018.

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  1. W2GAH

    W2GAH Ham Member QRZ Page

    Unit built many years ago (not by me) but as part of a Bell & Howell Schools correspondence course. It is labeled "Bell and Howell Schools Oscilloscope Model IOD-4540". I found schematic on line (included). It needs someone to trouble shoot and fix the horizontal Sweep Circuit. I had it working fine but the sweep all of a sudden went south. External sweep works and deflects but not Internal. I no longer have adequate equipment to trouble shoot. I'm down to an ole Tripplet Multimeter. Anyway it needs a good old fashion curious Ham Radio operator to bring it back to life. I do not want to trash it. It needs a good home and TLC. I wish I could but I can't.
    It is in very good shape. Some of the PC Board support posts need missing lock washers and nut, minor. OneCrt support post also needs a lost washer and nut, again minor. I have one condition and that is, you text or call when you fix it. I'm still a curious radio nut. I'm keeping a 2nd schematic to follow when you call ! $125 With free UPS Ship in Continental US
    2018 Scope 2.jpg 2018  Scope 1.jpg 2018 Scope 3.jpg
    Last edited: Nov 29, 2018
    KX4GG likes this.
  2. W2GAH

    W2GAH Ham Member QRZ Page

    As a follow up I combined a 60 hz signal to both Vertical and External Sweeps simultaneously to show H & V work (45 degree slope). Looks like H Internal sweep circuit has the bug.

    2018 Scope 4.jpg 2018 scope 5.JPG
  3. W2GAH

    W2GAH Ham Member QRZ Page

    May have to trash unit. If anyone interested make an offer. 1-1-28
  4. QRZ
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