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Thread: Monitor IIc troubleshooting - power LED but no HV or heater

  1. #1
    Join Date
    Jul 2017
    Location
    Portland, Oregon, USA
    Posts
    155

    Default Monitor IIc troubleshooting - power LED but no HV or heater

    Hi guys, I recently picked up a boxed Monitor IIc and stand to match my Apple IIc. (I have very fond memories of spending countless hours a day using my Apple IIc when I was a kid, so yes, trying to recreate this.)

    I was happy when I received the monitor in that, other than yellowing, it's in fantastic shape. I'm at the office so can't properly test, but a quick smoke test shows the power LED lighting up normally but HV and the heater doesn't appear to come on. I took a moment to open up the monitor and all seems normal inside (nothing obviously broken) ... and what's nice is it's very clean inside, no telltale signs of high number of hours.

    Anyway, I have downloaded and printed out the SAMS for the monitor, but was wondering if anyone has any tips of things to look for immediately.

    I recall my monitor when I was a kid had a bad solder joint leading to flaky video signal -- so I will take this apart and look for these. Looking at the schematics, I also see the power LED is run off the 12v power rail, which leads me to believe the power supply (And fuse) is good. But I do see the flyback and heater all appear fed from the same source from the power supply. (Source 4 on the SAMs)

    Thanks for any tips you can give!
    -- Adrian

  2. #2
    Join Date
    Jul 2017
    Location
    Portland, Oregon, USA
    Posts
    155

    Default

    Ok nevermind all of this. I plugged the monitor in to a video source at home and it came alive. I could hear the HV startup ... so I suppose HV doesn't run unless a video signal is being sent. Perhaps it's a 1984 version of "Energy Star" LOL

    photo_2018-09-05_15-21-42.jpg
    photo_2018-09-05_15-21-35.jpg

    Happy camper here. Now to disassemble it to clean and retrobrite.
    -- Adrian

  3. #3
    Join Date
    Jul 2017
    Location
    Portland, Oregon, USA
    Posts
    155

    Default

    Hey guys, so something interesting on my Monitor IIc. I have it completely taken apart and I notice the boards don't match what's in the SAMS schematics at all.

    https://imgur.com/a/xwDaXip

    For one, there are no H-Lin and H-size adjustments on the board -- just a fixed inductor by my thumb in the second pic. Then I notice an adjustable inductor on the yoke that measures out at 0.04mH. Is this the width?

    I did a bunch of googling looking for alternative schematics but no dice. Anyone have any ideas? I hope to keep this monitor for a long time so would love to be able to fix it if it ever breaks in the future.

    Thanks!
    -- Adrian

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