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<DIV><FONT face=Arial size=2>Hello Again,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks for all your helpful suggestions thus
far. I realize my first post was a bit vague, so I decided to test
more thoroughly and provide a schematic. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I've found the Pro-One schematics online; they
can be viewed at: <A
href="http://www.hylander.us/images/schematics/sequential/pro1-schematics.pdf">http://www.hylander.us/images/schematics/sequential/pro1-schematics.pdf</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>If you're on this list -- many thanks for
posting this on the web.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The column I'm having trouble with is D#0, B0, G1,
D#2, B2.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The continuity of the ribbon checks out fine.
(luckily its the computer-type removable kind)</FONT></DIV>
<DIV><FONT face=Arial size=2>On the keyboard pcb I've tested for continuity
from the slot for pin8 to each of the diodes of the problem
keys.</FONT></DIV>
<DIV><FONT face=Arial size=2>On the main board I've checked the continuity from
ribbon slot 8 to the leg of P13 of the U113 microcomputer IC
socket.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>From this I believe I can conclude that the leads
are intact going from the keyboard pcb to the IC socket.</FONT></DIV>
<DIV><FONT face=Arial size=2>Perhaps the next thing to check would be whether
the IC is properly seated in its socket (it looks like it is).</FONT></DIV>
<DIV><FONT face=Arial size=2>Would the next logical step be to replace the
IC? I've had a quick look at mouser.com was unable to find an IC
designated U113 or 8021. Any suggestions for a replacement?</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>-Tom</FONT></DIV></BODY></HTML>