69 lines
3.9 KiB
Plaintext
69 lines
3.9 KiB
Plaintext
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
|