29 Nov
1998
29 Nov
'98
8:56 a.m.
On Sun, 29 Nov 1998, Aaron Christopher Finney wrote:
I'm hoping someone knows about this (Don?)...
I got a parts-only Kaypro 4 from John Lawson yesterday, to try to cure the
ills of my "nice" 4. However, the two machines are quite different:
The one I got from John has the built in modem, a serial port, and both
paralell and serial printer ports; my original one only has a paralell
printer port and a serial port. Also, my old one has 2 eproms on the
board, one labeled 81-146 in socket U43, and one with a label "Specialty
Sys / STROKE.232 / Rev:1.5 08/84" in socket U47. Don Maslin hadn't heard
of this configuration before, so I'm assuming that it's some kind of
custom design. The one I got from John only has one eprom, labeled 81-292.
The new machine also has a 3v battery on the mainboard. The drives are
different too; the old machine has 2 full-height drives while the one from
John has 1/2 height drives. Part number of my old unit (from the back of
the case) is 81-004 and the part number of the one from John is 81-015.
Yours is a 4/83 while the one that you got from John is a 4/84. The 3v
battery is to maintain the real time clock that is also built in.
Now, I happen to like the nifty one with the build in
modem better. But
the video is fried (I said distorted yesterday, but there's nothing
legible on the screen) - there's only a little "noise" in the center of
the screen and an extremely high-pitched whine/screech coming from the
general areal of the video P/S.
So what I did, handling everything with [rubber] kid gloves, was swap the
CRT and boards, while leaving everything connected in the process. And I
got...nothing at all on the screen! I plugged the old mainboard in to the
new powersupply and connected it to the video and viola - perfect! So,
what gives? I noticed that some of the crystal frequencies are different
between the boards - is this what's causing it? Is there something simple
I can adjust to get the new machine to work with my original CRT
components?
If I understand correctly what you did, it would seem that there is a
problem in the mainboard video circuitry on your 'new' K4, since it does
not provide legible display with either of the CRTs or video boards. I
cannot tell you what it is, however.
- don
Also, any history/explanation about the differences in
the two machines
would be much appreciated.
Aaron