Monitor III display problem, please help

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Joined: Dec 20 2003
Posts: 52

I am trying to use my old monitor III (I am original owner) with my apple II plus. The monitor displays just a single line in the middle as pictured in the attachment. It does this plugged into the computer or not. None of the external adjustments do anything. Any ideas would be appreciated. Thanks

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Offline
Joined: Dec 20 2008
Posts: 209
Re: Monitor III display problem, please help

Vertical collapse. It will require board-level repair. If you don't know how to repair old CRT monitors, you could maybe find an older TV repair person.

It's likely just old cracked solder joints, but it could be a component that has failed.

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PINKBOY1006's picture
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Joined: Jul 9 2016
Posts: 90
Re: Monitor III display problem, please help

Looks like the vertical oscillator is not running. let me find the schematic and find the vertical circuit.

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My collection is: Apple IIGS Woz Rom 01 (cards installed: Uthernet II, Sandwich II card, Apple Video Overlay Card, Visionary GS), Apple IIc Rom 0 (Cards installed: Mocking board 4C), Apple modem 1200 (under the phone version), Apple personal modem, Apple imagewriter ii.

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Joined: Dec 20 2003
Posts: 52
Re: Monitor III display problem, please help

Thanks. I appreciate the help

PINKBOY1006's picture
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Joined: Jul 9 2016
Posts: 90
Re: Monitor III display problem, please help

Were the ic is on the board.

the circuit on the schematic.

check for continuity between pin 3 of the ic and ground. the resistance should vary when you twiddle with the vertical hold. if it does not, there is your problem. but look for broken solder joints with a bright light and a magnifying glass, on ALL solder points, if there is one, there ARE MORE look for them.

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My collection is: Apple IIGS Woz Rom 01 (cards installed: Uthernet II, Sandwich II card, Apple Video Overlay Card, Visionary GS), Apple IIc Rom 0 (Cards installed: Mocking board 4C), Apple modem 1200 (under the phone version), Apple personal modem, Apple imagewriter ii.