What you will need:
Two 27C256 Eproms
Zip file with two rom images
The above rom images are in a binary format.
Cut the power traces first. Turn the board upside down and locate the
line that connects to pin 28 of the two ram chips closest to the EPROMS.
This trace also provides power to the RAM decode chip IC32. Cut the trace
between pin 14 of IC32 and pin 28 of IC30. (Note that part of this trace
to the other side, runs a short distance and then comes back to the bottom
side to feed the decoder chip (IC32). Also make sure IC28 and IC30's (the
RAM's closest to the EPROMS) power lines are separated from each other.
Finally, sever the power trace that supplies IC28 (near pin 15 on the
bottom). To sever the other two RAM power lines, flip the board over (to the
top side) and locate the traces that provide power to the other two RAM
should be severed as close as possible to the Vcc pin (*28). Be careful
here, as there are several traces very close together - only sever the Vcc
After all the Vcc cuts have been made, check with an ohm meter to verify
that the pins are indeed isolated. Check from pin 28 of one of the EPROMs to
pin 28 on each of the RAM chips. There should be no continuity. Also make
sure that the RAM decode chip (IC32) IS connected to Vcc. Run a jumper from
pin 14 of IC33 to pin 14 of the decoder (IC32) if it isn't.
Next cut the CS lines. The first set of cuts should be made on the bottom
of the board. Locate pin 6 of IC32. A trace should run from this pin to a
feed-thru hole to the topside of the board. Make a cut here. This
disconnects the first set of RAM chips from the CS (RAM select) line. Find
the trace that connects pin 20 on the two RAM chips closest to the EPROMs
(IC28 and IC30).
Make a cut to this trace also. Verify that there is now no continuity
between pin 20 of IC28 and IC30 and between pin 6 of IC32.
Now you can cut the traces for the other two RAM chips - the ones furthest
from the EPROMs (IC29 and IC31). On the bottom of the board find the trace
that connects to pin 20 of IC31 (the upper RAM chip). Note how it forms a
small V shape where it goes to pin 20 of IC31 and then continues to pin 20
of the other RAM (IC29). Cut both sides of this little V in the trace. This
will disconnect the CS lines from pin 8 of the decoder (IC32) and the two CS
lines of the RAM chips. Verify this with an ohm meter. All cuts should be
Step 6 - INSTALL THE DS1210 BOARD
To install the DS1210 board, you must solder wires from the Vcc and CS lines
on the RAMs to the appropriate connections on each DS1210 chip. It's easiest
to solder the wires directly to the pins of the RAMs on the top of the
board. Note that while there are four RAM chips, they are arranged as two
banks with each pair having a common chip select line (See the enclosed MT
Both lines originate at the 74HCOO RAM decoder (IC32), pins 6 and 8. These
are labeled RAM SELECT 0 and RAM SELECT I on the diagram. Solder wires
to pins 6 and 8 on the 74HCOO and run these to your DS1210 board (Pin 5 on
the DS1210s - GE in). After these have been connected, run a line to provide
power to the DS1210 board. A good place to tap the power is from pin 14 of
IC24. Likewise, be sure to run a ground line from pin 7 of IC24 to the
A good place to mount the finished board inside the MT is on the MIDI jacks
at the back of synth. Use a little super-glue or epoxy to glue the board
Step 7 - CHECK THE MODS
Before installing the battery or the DS1210 chips, check ALL of the
connections with an ohm meter.
You should check each group systematically:
1) Verify that the Vcc is reaching the inputs of the DS1210s (Pin 8)
2) Verify that the CS lines are going to the DS inputs (from IC24, pin 6
to pin 5 of one pair of DS1210s and from IC24 pin 8 to pin 5 of the
second pair of DS1210s).
3) That all the proper pins of the DS1210s are grounded (pins 4,3 & 7)
4) That all pin 2's of the DS1210s are connected to the PLUS of the
5) That the MINUS side of the battery holder is connected to the MT's
6) That the outputs of each DS1210 (CE, pin 6 and RAM Vcc supply, pin 1)
go to the appropriate pins on each of the RAM chips.
After these have been verified, install the DS1210 chips in the sockets and
then insert the battery in the holder. Re-install the board and connectors
and power on. If everything is connected properly, the unit should powerup
normally. Check the battery backup by twisting the knob to bring up a
sound in each of the parts and adjusting the volume of each. Power cycle
unit and verify that each of the parts is how you left it. If possible, hook
the unit up to a computer and verify all the internal patches and tones are
preserved after a power cycle.
Depending on the vintage of your MT. installing our PROMS may only require
screwdriver. Early MT's had the EPROMS installed in-sockets so it is quite
easy to pry the old ones out and pop ours in. Later MT-32's require that you
install sockets and a certain amount of soldering skill is needed.
Even if your MT has soldered in EPROMS, we have come up with a method that
allows you to install sockets in your unit with simple hand tools. If you
are unsure of your abilities, find an electronics tech to do it for you.
Most music or computer oriented repair shops will put them in for a small
fee. If you wish to install them yourself, be advised that this modification
will void your warranty.
If you have purchased our optional installation kit, you will need the
following tools to install your ROMS: One small pair of wire cutters, a pair
of needle-nosed pliers or tweezers, a small wattage soldering iron, a solder
sucking tool or wire- braid solder wick and a small phillips-head
screwdriver. If you didn't purchase the optional installation kit, you will
also need two 28 pin solder type sockets, two ZIF sockets (these are
optional) and two new ROMS with the factory sounds in them (also optional).
Most of these items are available at Radio Shack or any electronics supply
store. The following procedure is the easiest and the least harmful to the
board. However, it does destroy the original factory chips. It is possible
to remove the chips without damage if you have the proper equipment (and the
patience), but this is not elaborated an in this document.
Read thru all of the following instructions and study the diagrams BEFORE
attempting this modification. If you have an MT with sockets already
installed, it is not necessary to remove the cables from the board or to
remove the board from the enclosure. Just remove the top and follow the
directions under the 'Install the ROMs section'.
Remove the Top
Disconnect all MIDI, audio and power cables from the MT and place it
down on a level surface. Locate the four screws on each corner that hold the
top shell of the MT in place. They are the ones right next to the rubber
feet. Remove these. Carefully flip the MT over right-side up and slide the
top toward the back of the unit. When the top is as far back as it will go,
angle it up to remove it.
Remove the cables from the board
See diagram. Be sure to note the correct polarity of the power connector.
Put a dot with a felt tip marker on it's top before removing it to make
replacement easier. All of the connectors (except for the small orange one)
have a 'catch' that needs to be deflected before the plug will come out of
the socket. Also, to get the ribbon cables free of the connectors, push down
on the tops of the connectors. This should free up the ribbon cables so they
can be gently pulled out.
Remove the board from the enclosure
Remove all of the screws holding the board into the enclosure. Be sure
remove the two screws on the back of the unit that hold the MIDI sockets in.
After removing all these, lift the board out of the enclosure and set the
enclosure aside for later.
Find the ROMs
Refer to the diagrams to determine the location of the two ROM chips.
are the two 28 pin chips directly beside the four long, skinny 28 pin RAN4
chips. They are labeled IC26 and IC27. On some of the early units (first two
digits of the serial number are 83 or less) the ROMs are socketed. With
socketed boards it is not necessary to remove the board from the enclosure.
Cut them out
Be absolutely sure you have identified the correct. chips to remove
performing this step ! Using a small set of diagonal (wire) cutters, clip
out the two ROMS. AGAIN be sure you have the right chips before you cut
As you cut each leg, leave a small section above the circuit board. This
will allow you to grasp and remove these in the next step. It is best to nip
the legs right at the point where they bend as they come out of the chip. BE
CAREFUL AND TAKE YOUR TIME WITH THIS STEP!! DO NOT DAMAGE THE CIRCUIT BOARD!
DON'T TWIST, BEND OR PULL THE CHIP OUT AS YOU MAY HURT THE BOARD.
Remove the remains
After the chips are cut and removed, use the soldering iron and the
nose pliers (or a pair of tweezers) to remove each of the cut off legs. Be
very careful not to damage the board as you pull each leg out. Keep the beat
on each leg only as long as necessary.
Clear the holes of solder
Using the solder sucking tool or the solder wick (we recommend t-he
Shack combination iron/solder sucker). Clear the holes of solder. After all
of the solder is removed, clean off the brown flux residue with flux remover
or isopropyl alcohol. A Q-tip works quite well for this. Be sure to clean
both sides of the board.
Install the sockets
Once the holes have been cleared, install the solder-type IC sockets.
small piece of tape to hold the socket in place. Flip the board and
carefully solder in the socket. Repeat this procedure for the other socket.
Once the standard sockets are in place, the ZIF sockets (highly recommended)
can be plugged into these. Note that there is a small capacitor soldered in
place between the two ROM locations. You may have to bend it slightly to get
the ZIF sockets to fit.
Install the ROMS
(If you have factory installed sockets, remove the original EPROMS at
Use a small screwdriver to pry them up. Carefully leverage them out a
A time, alternating from one end, then the other. Repeat procedure for the
other chip. BE CAREFUL NOT TO DAMAGE THE BOARD WITH THE TIP OF THE
Install the new ROMs in the sockets. Be sure the ROM labeled A goes in the
socket closest to the front of the unit. BE SURE PIN 1 OF THE EPROM IS IN
THE CORRECT LOCATION! Backwards installation may destroy the chip, upon
Put everything back together
Re-install the circuit board in the enclosure and re-connect all cables.
sure to secure the MIDI jack assembly with the proper screws. Before you
put the top back on, it's a good idea to test the unit to make sure
everything works correctly.
Power up and test
Do a final check on the unit and BE SURE you have all the cables and
connectors re-installed correctly. Connect the power cable and power up the
unit. You should see the message **Blue Ridge** briefly, and then the
normal part/volume display. If you see nothing or gibberish, power off
quickly and check all of the cable connections. If they are correct, go
back through the entire procedure and check all steps.