💾 Archived View for uscoffings.net › retro-computing › systems › Tandy › oldskool › romswk.txt captured on 2023-07-10 at 15:12:27.
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I did it! It works! Attention all DMP 2110 owners. It is
possible to convert your printer into something more usable.
It turns out that the DMP 2110 is a version of the Toshiba
P-351 Model 1, with the following changes:
1. According to Toshiba, all of the P-351 printers had both
downloadable fonts, as well as a socket for font
cartridges. The DMP 2110 has the download board, but not
cartridge circuitry. Interestingly enough, the Service
manual lists the font cartidge circuitry as an option,
even though Toshiba says they never built any that way.
2. The Tandy and Toshiba use different ROMS.
3. On the DMP 2110, the wires to pins 31 and 33 of the
parallel port are reversed (This means you have to use a
Tandy cable, or re-solder the connections in the
printer). The Toshiba's also had an optional serial
port. The DMP 2110 is parallel only.
Toshiba Printer BBS (714) 581-7600
While looking through the Toshiba printer bulletin board
@ (714) 581-7600, I saw a note about a "dual emulation
upgrade". It seems the early P-351 printers did not have the
IBM emulation mode. This was offered as an upgrade, and
careful reading of the Toshiba service manual showed that
this ROM upgrade would also give you Toshiba codes and get
rid of the Tandy mode.
I tracked it down to Toshiba National Parts,
@ (800) 624-5932. The part number for the 3-chip set is
M050-1430. Price is $160.00 plus shipping & handling. They
were out of stock, so the ROMS had to come from Japan, and it
took about six weeks.
The chips are labled as follows:
913A (replaces IC16 on the short download board)
911A (replaces IC17 on the long main board)
912B (replaces IC18 on the long main board)
I popped them in, set the dip switches according to the chart
in the P-351 service manual, and tried it with various
programs, and everything works great! On a hunch, I tried it
with all of the Toshiba drivers in Generic CADD Level3, and,
with a minor change in the driver, this printer appears to
run at 360 x 360 dots per inch! (I'm not sure if it's 360 x
180, or 360 x 360)
It seems that these ROMS I bought are not the old set
(limited to 180 x 180), but include the current code. Along
with some shimming of the print head with strips of paper to
get the lines exactly vertical, I now have a printer with
output better than the same drawing printed on a display
model HP Laserjet II. And it's faster with the Toshiba ROMS,
because more of the printer's memory is set up as a buffer
than with the Tandy ROMS.
The only down side is that the Tandy font software won't work
with the Toshiba ROMS. As of this writing (Dec '89) the font
software is still available from Toshiba. The font disks are
listed in the catalog from Toshiba Accessories Direct,
@ (800) 999-4823, but the catalog I have is dated Fall 1988.
If you order the ROMS, just tell them that your upgrading an
old printer. I can finally run the stock box labling program
I bought so long ago. Hooray!
Rich