MiniSport Laptop Hacker - Vol 4                        28 Nov 92

A few more folks checked in since the last issue.  It was good to hear from
KI6PL, N8OWM, N8PJP, KU8H.  These volumes come out pretty spuratically.
That's why they're labelled Volumes rather than Parts.  Each is put out on
the network as I have info to fill it.  Be sure to send me *your* informa-
tion! The rumor mill suggests a large pool of these machines is becoming
available in the Michigan area at reasonable prices.   That should provide
a much bigger pool of users to swap information.  Good!

One of the best purchases I've made recently is a CD-ROM.  I survive with
one Ham radio related disk and one shareware distribution disk.  Any of the
programs I refer to are likely sourced by these two CD-ROMs.  I would love
to share them with you, and it's encouraged by the program authors.  Make
it painless for me (disk SASE, clear request, etc) and I'll make copies for
you. If you're a "want it now" type of person, we can do a phone data
transfer.

>>> FLOPPY DISK SOURCE The strange 2" floppy disks problem seems to be a
perennial concern.  Here's all the non-rumor info I have.  Rex Television
Service Co  (7030 W. 111th Street, Worth, IL 60482-1827) sells a 10cnt box
for $45.00, but then tacks on another $10 for freight.  They also tried to
get me for sales tax, but refunded it later.  Phone 708-448-5558.  The box
I have indicates a lifetime warantee from FUJI, with the following Point of
Contact:  Fuji Photo Film USA, Inc., 555 Taxter Rd, Elmsford, NY 10523.

>>> FILE TRANSFERS I found COMMO and DSZ will work together on the MiniS-
port for what I need in less space than PROCOMM takes.  This allows packet
(or modem comm) with ZMODEM, YMODEM, and XMODEM protocols.  I tried using
DSZ with a hardwire between computers, using a null modem cable (FWL, which
is on your disk C:, is faster. Don't ask why I do these things!).  DSZ did
not like the 3-wire null  cable I described in MLH Vol3 that works with
FWL.  It needed to "hear" the  CD (Carrier Detect) on the serial port. Try-
ing to stay as globally portable as possible, here's a full blown null mo-
dem cable that lets you plug into almost any IBM/PC/XT/AT/'286/'386/'486/?
that you may come across.

 {9fem}--------4' 7cond cable------({9fem}----- 5" 7cond cable----{25male})
---------------------------------------------------------------------------
 0 (0 1)        DB-25 Frame Ground is not used
 1-6 (1-6 8-6)  Each feeds it's received DSR into CD, also
 2-(3-2)        Data to loner
 3-(2-3)        Data from loner
 4-(6-6)        DTR from loner goes to others' DSR
 5-(5-7)        Signal Ground
 6-(4-20)       DSR to loner from others' DTR
 7-(8-5)        RTS from loner to others' CTS
 8-(7-4)        CTS to loner from others' RTS
 9 (9 22)       Ring Indicator not used

The numbers to the left are pin numbers.  Wires are represented by "-".  In
the text description, "loner" refers to the computer at the lone connector
end.

DSZ supports much more widely-known protocols.  For that reason, it has
been important for me to get running.  It's still in an evaluation stage at
this QTH.  If you have any experience with this program, I'd be interested.
But be assured that Zenith did you well by providing FWL.  It is an order
of  magnitude faster for local hard-line transfers.  I've not tested FWL
over the phone line.

SWAPPING THE SECOND MEGABYTE
I had two MiniSports.  The 2M one had a power supply problem.  It would
work work for a week or so and then no longer power up.  Each time, I took
it apart, wiggled all the connectors, put it back together and it worked.
The fourth time around I decided "enough!"
I unsoldered the single-inline-pins of the add-in memory package (8 bits by
1 Mbyte).  I resoldered into the same position in a second machine that was
working reliably as a 1M system.  The memory package's pins are not actual-
ly the pins of the ICs, so I wasn't too worried about heat damage.  I used
an alligator clip between the soldering iron and the computer ground.
No jumpers, solder traces, etc needed to be modified.  I reran the SETUP
option (hold ESC on power up), specified new memory sizes in both, and,
voila!, they both have worked fine now.  I'm still waiting for the old 2M
to fail again.

If you have any supply information on 1Mbyte x 8bit SIP (or SIMMs, I'll add
the pins), please let me know!  I'm confident that I and other hams can
successfully double the memory in a 1Mbyte version of the MiniSport.

Next time, DISASSEMBLY INSTRUCTIONS, POWER SUPPLY PINOUT, MINIMUM BOOT
FILES, and discussion of BOARD REVISIONS.

73, Brian, ka9snf@wb7nnf,#spokn.wa.usa or Internet ka9snf@jupiter.spk.wa.us
