Re: //c display problems, etc.

[dempson@actrix.gen.nz (David Empson)]

<aclark@essential.org> wrote:

> I just got a 4000 //c.  The 9 inch mono monitor is displaying two
> flashing zeroes and a few tiny, diagonal lines on the screen all the
> time.  Other than that there are no display problems.  Anyone know what
> might be causing this?

If they are always appearing in the same positions, and never go away,
it is probably faulty RAM.  Do they get duplicated vertically when the
screen scrolls?

> This //c is not capable of using a 3.5 Unidisk, so I am planning to put
> a newer //c motherboard in to solve that problem.  Can this be done?  Is
> the older case compatible wth the newer motherboards?

I haven't seen the later motherboards, but I'm pretty sure that all
versions are mechanically identical.  The IIc+ is the obvious exception
to this.  (The memory expansion IIc adds a connector for the expansion
card, which may require removing the support bracket under the keyboard
to be able to fit the card, or they may have redesigned the case
slightly to make more room.)

In any case, you don't need to upgrade the motherboard to support the
UniDisk 3.5: it just needs upgraded firmware, and a couple of minor mods
to the motherboard to allow for the larger ROM.

You might like to replace the motherboard anyway, to fix the display
problem (and possibly others).

If you upgrade to a later motherboard version, you can avoid the serial
port speed speed compatibility problem of the original motherboard (the
serial chips run somewhat slower than the standard baud rates, which
causes compatibility problems with some devices).

-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand