Kaypro help, again...

From: Don Maslin <donm_at_cts.com>
Date: Sun Nov 29 16:56:09 1998

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
>
>
Received on Sun Nov 29 1998 - 16:56:09 GMT