MiniSport Laptop Hacker - Vol 1 
 
As some of you may know, Zenith has gotten out of the business of selling 
personal computers.  I had the good fortune to purchase some of their ex- 
tremely small MiniSport laptop computers.  They are absolutely perfect for 
packet use and in any RACES or ARES setup, they could provide other func- 
tions as backups due to their universal hardware platform.  I thought oth- 
ers might be interested in information I've collected in case you're using 
one or interested in buying one. 
 
If *you* have information, please pass it on to me.  I'll bundle it up and 
send out a MiniSport Laptop Hacker Part 2! 
 
These computers are basically an IBM/PC platform with 1 or 2 Mbytes of RAM, 
MSDOS 3.3 in ROM, a 2" floppy, and a 25x80 column LCD screen.  RAM above 
640k can be used for EMS or battery backed RamDrive.  They have connections 
for an external CGA monitor, an external floppy, serial port(s), and a par- 
allel port.  Primary connection to other computers is via a 3-wire or 7- 
wire (faster baud rates) null-modem cable.  FastWireLink program is includ- 
ed in ROM with MSDOS, logically on drive C: 
 
The 2" disks are hard to locate, but I finally found a source for them, 
albeit an expensive and un-friendly one: Rex Television Service Co., phone 
708-448-5558. 
 
I had a power supply problem with one.  I unscrewed the case and innards of 
the offending unit and learned a lot. The interior is modular and easy to 
work on: Power supply, Main CPU board, Keyboard, Disk Drive, and LCD dis- 
play. Multiconductor ribbons connect the parts.  If you open yours up and 
slide the main PC board out, be carefull of the POWER SWITCH and the disk 
drive EJECT BUTTON.  Both get caught easy on the case and might snap some- 
thing.  The only tricky part is that one of the drive mounting screws needs 
to be unscrewed before you can release a thin piece of copper ("Mu metal") 
colored grounding strap wrapped up and around the main PC board from below. 
 
Like I said, I had a power supply problem with one.  To the best of my 
knowledge, it's an intermittent cable contact.  Each time it fails, uncon- 
necting & reconnecting the one PS cable fixes the problem.  It's a 15 min 
operation and is not complicated.  I'm thinking of swapping power supplies 
around.  I have the pinout of the PS connection to the main board, if you- 
're interested.  You could test the PS by only taking off the bottom com- 
puter panel and measuring voltages from the "underside" of the circuit 
board. 
 
The unit is powered by a removable battery that reminds me of a cam-corder 
battery.  It's advertised to be 6v. I suspect it's five NiCd cells (5x1.2 
=> 6.0).  The computers power supply/ charging receptacle is on the battery 
pack and feeds connections further into the computer.  I've tapped into the 
wierd shaped connector with paper clips.  Alternately one could bypassed 
the battery entirely by clipping alligator clips onto the sliding contacts 
on the computer.  The batteries will charge with a 6volt supply, but the 
computer runs from 9volts DC if it's not using batteries. 
 
As I hinted above, a second serial port is available.  It's logically 
there, but terminates mechanically in a Scotch-Flex type socket.  It's 
meant to accept a modem module.  I'm currently trying to determine a pinout 
for this connector.  If you have the information already, perhaps you could 
pass it on to me. 
 
The external floppy drive connector has been as difficult to find as the 2" 
floppy disks.  It is a square outer connector, with a female D-shaped re- 
ceptacle.  The D-shaped receptacle has 20 pins.  It's just under 3/16" tall 
and just under 5/8" wide (at the wider side of the D).  If you have any 
PINOUT OR ACQUISITION INFORMATION for this type of connector, please send 
me a message and I'll include the information in round 2 of the MiniSport 
Laptop Hacker. 
 
73, Brian, ka9snf @wb7nnf.#spokn.wa.usa 
