8 Jun
2010
8 Jun
'10
12:13 p.m.
I have an IBM model M2 here which when plugged in, the Num lock and
Plugged in to _what_?
Is it possible that the host machine is sending some command to the
keyboard that it doesn't recognise?
scroll lock leds go on, and the keyboard refuses to do
anything. I
notice that SOMETIMES the Model M I have here does the same thing
(num+scroll on, no response) for a few seconds, and I'm GUESSING it
might be something like the 5v line can't supply enough current to run
it properly at startup, but it usually starts working after about 3 or 4
seconds; the M2 does not.
Have you checked the 5V line in the keyboard?
The keyboard contains a microcotroller (8048 IIRC) which is reset by an
RC network in the keybaord, it doesn't sue the system reset line. i
suppose if the 5V line was risingtoo slowly, then the microcontroller may
not initialise properly.
Any idea what causes this, or whether it is fixable?
Not off the top of my head. I think you need to do some more measurements...
-tony