TT: Intermittent phantom key & mouse button presses.

[stephen_usher]

OK, here's another strange one.

Every now and again my TT decides that either the right mouse button is constantly pressed or Ctrl-Space is being typed repeatedly but intermittently. This happens with any mouse in the port, so it's not the mouse. The 5V line is something like 5.08V and as smooth as silk according to the oscilloscope.

When this happens a warm reset (Ctrl-Alt-Del) or the reset button doesn't fix it but a cold boot (Ctrl-Alt-Shift-Del) does. Unplugging and replugging in the keyboard makes no difference.

All I can think of is that the pull-up resistor on the keyboard RX line is going faulty and the line is floating, causing the system to think that the keyboard is in some strange state, or there's some other hardware problem lurking somewhere. A gremlin that's being fed after midnight.

Any ideas?

[exxos]

Wasn't this some OS bug which was never solved ?

[mikro]

AFAIK, that is the ESC bug.

[stephen_usher]

Oh, I've not heard of that one. What is it precisely?

The reason I asked is that I've been seeing the problem more and more recently. I've switched over to using an Eiffel temporarily as the TT keyboard was becoming almost unusable some days.

[arkadiusz.makarenko]

Was it a bug in MPU firmware or OS?

[stephen_usher]

After resoldering the DB9 ports and all the other connectors on the keyboard board and cleaning the DB9 contacts with very fine sandpaper the keyboard seems OK again. I wonder if it was poor contacts making spurious signals.