> Since I did get an error "keyboard clock line failure" I expect there may
> be a problem with pin 5. Anybody know what reading to expect on that pin?
As I recall, the PC should be dumping a nice clock signal down that line.
Not sure of the frequency, but around 4MHz or some multiple would be a
guess. If you've got an oscilloscope, see if you can get a square wave out
of it.
> Or pin 1 ?
The keyboard should send a pair of bytes on pin 1 when power is first
applied - the keyboard controller does a self check and sends this 'I'm OK'
sequence when everything passes (I would have been able to tell you what the
bytes were, but someone's tidied my desk while I've been away. E0 FF or F0
FE ring bells, for some reason). When the PC is turned on, if the three
status LEDs blink the keyboard is getting power and has sent those two
bytes - there's no way that the keyboard can be powered up without that
happening (even my minidisc deck does it).
As an aside, I meant to say this earlier but forgot - if you've got a
motherboard spare, try swapping the keyboard chip over (it's a ROM IIRC, so
quite large and usually with a sticker on the top - I think mine are
AnyKeys). I've seen machines where that chip let out the magic smoke, and
worked fine when switched with a chip from a dead motherboard.
Regards,
Ben A L Jemmett.
(http://web.ukonline.co.uk/ben.jemmett/, http://www.deltasoft.com/)
To unsubscribe from SURVPC send a message to [EMAIL PROTECTED] with
unsubscribe SURVPC in the body of the message.
Also, trim this footer from any quoted replies.
More info can be found at;
http://www.softcon.com/archives/SURVPC.html
