Monitor issue

Electronics Computer Programming Q&A
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psycho
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Monitor issue

Post by psycho » Thu Oct 29, 2009 2:04 pm

Hmmm. My old HP mx705 CRT is "acting" like the "+" button is always pressed. The brightness setting is always displayed on screen. My first thought was a stuck button but it doesn't seem to be. Before I rip into it, anyone ever run into this before?

Thanks,
Kevin

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Externet
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Joined: Fri Feb 01, 2002 1:01 am
Location: Mideast USA
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Re: Monitor issue

Post by Externet » Thu Oct 29, 2009 6:51 pm

Hello Kevin.
Try disconnecting the wires from the button panel to the mainboard to rule out a stuck prone tact switch.
If the behavior persists, follow the traces from such connector to a µcontroller on board; somewhere along the way a resistor pack may exist to pull up/down the µcontroller keypad-assigned input pins. Check voltages to each; check the health and solder on all the resistor pack sections. Come back with findings, :smile:
Miguel
- Abolish the deciBel ! -

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