22 Feb
2011
22 Feb
'11
9:25 p.m.
On 2/22/2011 11:42 AM, Tony Duell wrote:
I just got done trying this. No dice, with the membrane disconnected 3
of the LEDs light up constantly and that's it (no beeps or anything
else). With the membrane connected I get 4 LEDs and a few very short
(shorter than I recall under normal circumstances) beeps. So perhaps
the membrane isn't to blame in this case.
Thanks for the suggestion, though. Maybe later this week I'll have some
time to do some debugging on it...
Josh
Thanks -- I
don't know why I didn't think to look at that in the first
place. Turns out there are diagnostic LEDs on the board (helpful!) and
they indicate "keyboard failure". This is the only compatible keyboard
I have, and I had previously been using it with my VT220, so I was
fairly sure it was working (but it's been at least a year since I last
powered it on). I dug out my VT220 and sure enough, the keyboard fails
there too...
Most of the time LK201s fail becuase of a problem with the membrane
switches, not the cotnroller board.
You might try taking it apart (the screws are under the push-in plastic
feet), remvoig nthe unit from the bottom case (frob the clip and slidt it
to release it), then removing the control PCB fixings (clip on the
regulator, and 1 screw). Then bend up the tabs on the metal clamps that
hold the mebrrane tails to the PCB and take them off.
Try connectin the PCB alone to the VT220. If it passes, try it on the
microvax too. If will at least let yoy know if the latter is likely to
work with a good keybaord. Alas I have never managed to dismantle the heat-staked
membane in a way
taht it can be reassembled :-(
-tony