Problems adding second hard disk

[David B. Thomas]

caa at com50.c2s.mn.org (Charles Anderson) writes:

>A frien and I have been trying to add a second hard drive to my 3b1 without
>much success.  It's a wren II 86meg drive (72 meg formatted).  We constructed
>the ICUS board, and plugged it in, and when we try to format the drive it
>doesn't even access it.  We originally had problems with the cable coming
>off of the ICUS board going to the HD since the pinouts for the connector
>aren't listed in the instructions...but I think we got it corrected...

Okay... first of all the ICUS directions suggest a pinout for the connector,
but other than the +5v and GND which are hardwired, the other pinout decisions
are yours.  I used my own nonstandard pinout, and actually, I suspect that
might be one of the reasons why I had such terrible noise problems when I
tried to use it. (while other people's unit worked fine)

Now, if what you mean when you say "doesn't access it" is that the light
doesn't come on, then something very simple and fundamental is wrong.  The
second drive needs to be configured as drive 2, and have a terminator,
and drive 1 needs to be set up as 1 (as always) and not have a terminator
anymore, since it's no longer at the end of the chain.  Try probing the
"DDRIVE1" line and see if it goes active when the computer is told to access
the drive.

>any ideas...I got the plans for the ICUS board years ago, does anyone have
>a better board?  maybe one with a PC board....my friend did my board with
>wire wrap thats soldered on but I'd feel better with a real PC board.

In fairness to Gil & Lenny, a lot of ICUS boards are out there humming away
happily.  I had bad noise problems with mine, but your problem sounds like
a simpler problem to fix.  If you like, I can send you some info about how
I did the upgrade on the motherboard itself, by piggybacking IC's and keeping
lead lengths to an absolute minimum.  John Milton has a PC board upgrade,
called the HD2.  I'm not sure how that project is going (John?).

With a voltmeter, you should be able to follow the drive select logic and
see what is or isn't happening.  Good luck!

						little david
-- 
Unix is not your mother.