UPDATED for
2010!
Do It Yourself
Special:
FREE plans
to add
MIDI
capability
to the
Roland
MC-202
with the
Synhouse
Original
MIDIJACK!
Extensive
updates added to this page in
September 2009 and February 2010:
The Roland MC-202 was a late bloomer, with only a few MC-202s having
Original
MIDIJACKs installed in them for the first few years after the first
MIDIJACKs were installed in 1999, but the MC-202 has gone on
to become one of the most popular Original MIDIJACK applications (after
the Roland SH-101, which is the most popular MIDIJACK app by a good
margin). Many questions have come in, and it is apparent that people
all over the world are reading these plans and trying to work them on
their own at
home, so it was decided to rework them with many more photographic
illustrations to demonstrate the somewhat complicated tasks that the
original text described as if they were so simple they needn't be
illustrated.
Additionally, Synhouse has discouraged MC-202 Factory Installations for
a while now, as they take a tremendous amount of time, require an
unreasonable amount of care and caution due to the fragility of the
MC-202 inside and out, and the job creates an incredible mess of the
workspace, throwing crumbs and shards of plastic everywhere.
Therefore,
this article has been vastly improved and simplified to encourage
people to do their own free self-installations.
This page has been reworked and updated at least twice
before, but this is by far the biggest update yet.
First, some performance notes should be added here. Many people have
complained that the MIDIJACKs play the notes too high and can't do any
decent bass. This is completely wrong, the MIDIJACKs can always play
notes as low as the local keyboards of the synths, and in the case of
the MC-202, it can play notes much lower.
Specifically, MIDI note 0, which can be sent by any good MIDI
controller (or even a lousy one like the Roland Juno-106 with the
Original MIDIJACK MIDI Transpose Select Mode set to -36 half steps/3
octaves down, that is what that is for) will make the Original MIDIJACK
play a note on the Roland MC-202 that is semitones lower than the local
keyboard was ever able to play. The origin of most of these bogus
complaints are users not reading the manual and not understanding the
significance of the incredible 10+ octave range of the Original
MIDIJACK, which means that at the standard (untransposed) setting, the
instrument will be playing notes many, many octaves above what the tiny
junk local keyboard was ever capable of playing.
Second, the quality of the installations done here and the attention to
detail has improved considerably over ten years, with more time being
spent on most of
them for various reasons. More
specialty tools are used in these installations, and instead of making
the installations go quicker, it makes them take longer, to do neat
procedures that would have been simply skipped otherwise. In the case
of the
Roland MC-202, the problem, at least in terms of the time it takes when
the installation is done here, is all the work done nibbling away at
the plastic. It is not just on the outside that you can see, there is
10x as much plastic work done on the inside that you can't see. Users
probably do the installation more quickly than it is done here.
Why?
Because they do sloppy work and don't
have the tools to do it right
(Dremel Moto-Tool). The work done here is super clean, beyond super
clean, and it is a very, very rare occasion to see work done by users
or other shops that is as cosmetically clean as the work done by
Synhouse.
Most people don't focus on the
tiniest details,
nor even pay attention to
important ones.
For example, the plans specify
the
exact size of drill bits to use to
get a precise fit with smooth operation for the tact switch and for
best accessibility for the trimpot scale adjustment, but almost any
installation seen in the field (not done by Synhouse) has had those
specified hole sizes simply ignored. It
is common for people to complain about how cheap and crappy the
MIDIJACK switch
is, and they occasionally ask how to replace it with something better.
Well, the old tech
"something better" they have in mind is invariably something that has a
lifespan rating
that isn't even 1/10th of what the MIDIJACK tact switch is (the
MIDIJACK tact switch is rated to withstand over 500,000 presses), nor
does it
provide the required tactile feedback. They break the switch because
they mount the board wrong. Instead of using the perfect size drill bit specified by
Synhouse (the perfect
size drill bit for the switch stem and
two screw holes is 9/64"),
they blow a 50-acre hole through the side of the synth
so that the switch swings back and forth like a joystick, eventually
tweaking the contacts or just breaking off entirely.
Not one switch installed by Synhouse has failed. Ever!
When mounted in the right
size hole with the right use of the washers as depth shims, it is
almost impossible to break that switch. It will outlast the entire
synthesizer.
It is for good reason that the
MIDIJACK articles are
3,000-4,000 words long each, instead of just one paragraph. Every
detail is
useful.
When the MC-202 installation is
done
here, the Original MIDIJACK board is put in the
battery box and the plastic chassis is chiseled out to accommodate
that.
The last one that was done here (June 2009) took 6 hours
and ten minutes, and that didn't include changing the plug on the
power supply. The plastic work with the Dremel took 2 hours and 35
minutes alone. A user would probably skip that step, because they don't
have a Dremel Moto-Tool (nor know what it is), and do the plastic part
of the installation in just a few minutes, by simply removing the
now-unneeded battery box
inner cover and outer lid. They would also probably skip the heat
shrink tubing and epoxy potting because they don't have heat
shrink tubing, a heat gun, or epoxy resin.
When the installation has been done here in recent years, this extra
tedious work was done just to make it perfect, so it didn't have a
gaping hole in the back, and so the inner battery box cover could still
be firmly screwed in place to provide stiffness and strength to the
MC-202, which is one of the flimsiest musical instruments of all time.
It is difficult to rank them in a specific order, but all the top five
are Roland models for sure (TB-303, TR-606, SH-101, etc.).
This brings us to another important point about why the MC-202 is such
a difficult instrument to do a quality MIDIJACK installation in, the
poor physical construction of the MC-202 itself.
While the circuitry of the MC-202 has a great sound, the physical
construction of the MC-202 can be described, in strictly scientific
terms, as a shit sandwich. It is all plastic outside with garbage
inside. Even parts that absolutely must
be made of metal aren't made of metal, like the shielding boards, which
are paper with a metallic finish.
The MC-202 PC boards are of a quality grade that is about a thousand
steps below the quality of the Synhouse MIDIJACK circuit board. Instead
of being made of FR4 epoxy impregnated 94V flameproof fiberglass as
anything from any decent company is, the PC boards that Roland used in
the MC-202 (and Juno-106, and no doubt hundreds of other products) are
made of paper phenolic. PC boards made out of this material are about
as durable as stale saltine crackers. Some of the Roland PC boards
aren't even double sided, they are single sided paper phenolic PC
boards. This is a grade of material so low that it is doubtful that a
reputable PC board vendor in the United States could even supply it.
All PC boards should be double sided. It has nothing to do with the
need to have components on both sides, it is because a board that is
copper clad on both sides and has the holes copper and tin plated all
the way through, connecting the top and bottom sides both physically
and electrically, is vastly stronger and has better connectivity over
the long haul.
With this in mind, the installer must
exercise extreme caution when doing an installation in an MC-202.
For example, the simple act of separating the upper and lower circuit
boards by pulling them out of the plastic standoffs can crack the PC
boards themselves. If this happens and you are lucky, you will see an
obvious crack, but if not, it will be some hairline cracks that you won't see, and constant or
intermittent problems will result. Many Roland Juno-106s, etc., have
been seen in apparently good cosmetic condition but were not working,
and the problem was found to be a cracked PC board inside.
The pricing for some
installations has been changed, with the MC-202
being highest. If the amount of time spent on the last one (including
power supply) were spent on any other service work done here, like repairing a
Fairlight or Synclavier, it
would
have been a $350 job, period.
Since the MIDIJACK is a mature product now, there is no reason to do
charity work on it, so the pricing was changed.
Since the MC-202
pricing should be constrained closer to what the resulting MIDI MC-202
is really worth, there is some discount, but the current pricing is
well more than double
what it had been in the past.
Don't like the price? Fantastic! Do it yourself for FREE using the
plans below.
For this reason, the MC-202
article below has been improved to make it easier for customers to do
free self-installations.
Even with all
this said, once the
Original MIDIJACK is installed, the MC-202 is a self-contained
MIDI analog monosynth, only requiring the external power
supply, and for this reason, the Original MIDIJACK is better than
everything
else and no MC-202 should be without it.
There is another option available for
the
MC-202, the Synhouse MIDIJACK
DINSYNC,
which is cheaper, easier to install, and can use either battery power
or the original Roland external power supply (which is insufficient for
use with the Original MIDIJACK), but it subjects the user to the
considerable limitations of the MC-202 sequencer.
The updated article is below:
The
following
plans describe a method of adding MIDI capability to the Roland MC-202
with the Synhouse Original MIDIJACK. The Original MIDIJACK converts
the Roland MC-202 into a MIDI analog synthesizer module, allowing
you to use a proper MIDI sequencer with full editing capabilities
instead
of the tiny internal sequencer. The MC-202 is especially well suited
for this modification due to the tiny size of the MIDIJACK circuit
board
and the fact that it is the first analog MIDI retrofit ever made that
costs
less than the instrument itself! The Original MIDIJACK will control
the MC-202's internal portamento circuit to make it think that it is
playing
a sequence programmed with portamento so that the the MIDI notes will
have
the amount of glide set by the portamento pot position.
Please note
that the CV/gate input jacks on the MC-202 are so poor that they are
useless
for most musical purposes. The incoming CV/gate signals are
regurgitated
through the internal sequencer, slowed-down and quantized to the
poor DAC resolution of the MC-202. Thinking of using some type of
external MIDI control box through these CV/gate inputs? It isn't
nearly as good as using the Original MIDIJACK. The newer Synhouse
technology provides much greater DAC resolution, twice the
note range,
and the world's fastest MIDI response. This modification reroutes
the internal sequencer signals through the computer-controlled analog
switching
matrix of the MIDIJACK by extracting the signal and inserting the
users'
choice of local sequencer / tiny keyboard control or MIDI. There
isn't any space on the MC-202 to easily install any type of MIDI
retrofit, but with some creativity and careful modification, it is
possible
to install the Original MIDIJACK, making it the world's only internal
MIDI retrofit for the MC-202.
You may be able to do this yourself
if you have experience with electronic repair and the soldering of
wires
and circuit boards. If not, Synhouse can provide Factory
Installation. This way, the Original MIDIJACK can be properly
installed in the Roland MC-202 by Synhouse without risk. The labor for
this
one
is priced higher than any other synthesizer for the
reasons
stated above, plus current costs for
the new external
power supply required for the MIDI upgrade. This price covers the
cost of the labor and supplies used for the upgrade but does not cover
shipping the synthesizer round-trip to Los Angeles, California. The
user
must also purchase the
Original
MIDIJACK from Synhouse at current pricing. Check with Synhouse
Factory Installation for the latest information on the pricing and
availability of this service. The customer is not required to supply
schematics for this particular installation, as it is well known
to Synhouse. The work will be performed within approximately ten
business days.
For self-installation, it is best to print these notes out on paper
to look at while working on the instrument and make notes and check off
the steps as you go. As with any project, it is best to completely
read and understand each step of the instructions before starting.
The particular installations on which this document is based were
Roland
MC-202s serial numbers 327400 and 340300, other revisions may be
different.
All
repairs and modifications made to your instruments will be done at your
own risk and Synhouse Multimedia Corporation assumes no liability for
personal
injury caused or damage to equipment or loss of use caused directly or
indirectly by the use of these plans. If in doubt, don't do
it!
Instructions:
1) Be sure to have the correct tools
and supplies for for the job. If you do not have them, get
them. You will need a regular size Phillips screwdriver, a
smaller size Phillips screwdriver, needlenose pliers, wire
cutters or other flush cut nippers, a hobby knife such as an X-Acto,
scissors, a soldering iron, solder, electrical insulating
tape (or heat shrink tubing if you have it because it never becomes
sticky or falls off), and a black Sharpie permanent ink marking pen.
You may
wish to use a Dremel Moto-Tool to carve out the plastic to make way for
the DIN jack and circuit board, and a low-speed electric drill with
a 1/8" or similar size drill bit to drill holes for the 4-40 hardware
used
to mount the DIN jack. A DMM (Digital MultiMeter) with the continuity
test function is absolutely required to do this job. It is the only
sensible way to locate and verify the proper points.
2) Fully test the Roland MC-202 to
be converted to MIDI. Be sure that all functions work. If it
doesn't work properly without MIDI, it certainly won't work with
it.
3) The installation of the Original
MIDIJACK in a Roland MC-202 is fairly straightforward from an
electrical
standpoint. The difficulty comes when trying to fit the new MIDI
hardware inside the tiny plastic case without damaging the extremely
flimsy MC-202. The installer must cut copper
traces on the circuit board to isolate and access the correct DIN sync
I/O signals. This modification reroutes the internal sequencer and tiny
keyboard signals through the computer-controlled analog switching
matrix of the MIDIJACK by extracting the signals and inserting the
users'
choice of local internal sequencer and tiny keyboard control or MIDI.
The
whole MIDI conversion job might take 5-10 hours, depending how
crafty you get chiseling away bits of plastic to get a good fit. This
is one installation not to be rushed.
4) Remove the seven Phillips
screws that hold the lower case in place. Remove this piece.
5) Turn the instrument upside down
and shake out any dust and debris that may have accumulated inside the
instrument over the years.
6) Remove the knobs and slider caps
and remove the upper case as well. Place the board on a soft
nonconductive
surface.
7) Determine the place where the
MIDIJACK circuit board and DIN jack will be mounted and test fit the
board
into its' correct place inside the case. You may wish to use different
mounting hardware for a low-profile installation as described in the Original
MIDIJACK Advanced Installation Manual. This will be the most
difficult
part and it is left entirely up to the installer.
The easiest place
to mount the board and DIN jack would be inside the battery box. The
battery box will no longer be needed, as the Original MIDIJACK-equipped
MC-202 cannot be battery-powered, it must be used with a new external
power supply to get the full 10-1/2
octave MIDI note range.
Originally, the test unit done by Synhouse for the purposes
of writing this article was done another way, where the battery box
was left empty and the MIDI input DIN jack is on the lower panel piece
in the right rear corner facing out to the right hand side, and the
MIDIJACK board is mounted with smaller 4-40 hardware under the control
panel just to the rear of the VCA section, as seen here in MC-202-pic1:
This makes for a cleaner installation,
but more than doubles the amount of time required to do the work.
This spot is a very tight fit and much care must be taken to get the
holes
drilled in precisely the right places and to avoid short-circuits.
There is literally no space for the standard MIDIJACK board
configuration
here so the aluminum mounts were removed and shorter ones were held in
place by epoxy glue. Some electrical insulating tape was placed over
the top of the electronic components beneath the MIDIJACK board to
eliminate
the possibility of short circuits if the epoxy came loose and the board
came down. This way, no matter, it has nowhere to go, it is trapped in
the 10 millimeters of space under the control panel.
Eight years later, for the update to this article, it was done in the
easier manner recommended above, by putting the Original MIDIJACK board
in the battery box, as seen here in MC-202-pic1a:
The internal views
of this mounting of the board in the battery box can be seen here in
photos MC-202-pic1b, MC-202-pic1c, MC-202-pic1d, and MC-202-pic1e:
The inner battery box cover, though no longer needed to hold the
batteries in place, can be put back in place to provide chassis
stiffness. In order to do that, you will need to cut a hole for board
clearance.
In the example shown below in photos MC-202-pic1f, MC-202-pic1g, and
MC-202-pic1h show the hole having been marked with a Sharpie pen,
started with a pilot hole to provide additional clearance for the
optoisolator that protrudes from the board, and finally being cut with
a Dremel Moto-Tool:
Tip: A hot knife might do this more quickly and without throwing plastic chips
everywhere.
In the years since
the MIDIJACK first came out, a new tool has appeared in stores, the
step drill. While hardly a professional grade tool, they are very low
priced, selling for as little as $15 for a set of three at
Harbor Freight Tools, and
would be a cheaper and faster choice than a chassis punch for users who
need to mount the DIN jack in the synthesizer chassis. In the case of
the el-cheapo plastic case of the MC-202, the chassis punch could never
be used, but the new step drills can cut the hole much more quickly
than an X-Acto knife ever could, as shown in MC-202-pic1i:
Photos
MC-202-pic1j, MC-202-pic1k, MC-202-pic1l, MC-202-pic1m, and
MC-202-pic1n show the hole having been
trimmed up with an X-Acto knife, extra holes drilled for mounting and
screw clearance, and the DIN jack installed after the contacts were
bent slightly inward for clearance:
Photos
MC-202-pic1o and
MC-202-pic1p show the battery box door having been
trimmed with a Dremel Moto-Tool to provide clearance for the DIN jack:
The Original
MIDIJACK accessory packet has paper drilling templates to act as a
drilling guide while making the holes for the board and DIN jack. Once
carefully taped in place, the holes may
simply be drilled through the paper. Do not use a high-speed drill
when drilling plastic. The chassis pieces of the MC-202 are made
of soft plastic and a high-speed drill will build up friction, generate
heat, and burn the plastic permanently. Drill at the slowest
speed available. The perfect size drill bit for the switch stem and
two screw holes is 9/64", and the perfect size for the scale adjust
trimpot is 3/16". Drill the holes. If your drill is not slow
enough to safely drill plastic, you can use an X-Acto knife to make
the holes by twisting. This is a little more time-consuming,
but works well if you don't have a drill to use. You can use a standard
X-Acto knife blade with the sharp point and twist it in place until it
starts to dig a little hole. When it gets close to reaching the other
side, you can look outside and see the tip coming through and dig
back from the outside as well. A perfectly round hole can be shaped
using this technique.
8) Obtain a new power supply to use
the MC-202 with MIDI. The original BOSS PSA or Roland AC adapter
has an output voltage that is too low for the MIDIJACK. The MIDIJACK
must have at least +12 volts DC input to allow it to be stable and put
out the top MIDI note 127 which is +10.58 volts. The original Roland
unit was said to be +9 volts DC, but when measured under load it
was found to be +11.53 volts and dropped after some time. The MC-202
uses an old but clever powering method which allows portable operation
with 6 "C" cells, which comes out to only +9 volts total if the
batteries
are good. When an AC adapter is plugged in, the DC IN jack
switches out the connection between the batteries and the synthesizer
circuitry. If this AC adapter provides only +9 volts, that is fine, or
if the AC adapter provides +17 actual volts that is okay as well.
The MC-202 has a DC-DC converter that
steps
up the voltage to about +20 volts unregulated, then runs it through
a linear voltage regulator that puts out the regulated +15 volts that
the
analog synthesizer circuitry runs on. To check and see how it is
working, both before and after you replace the original power supply,
measure the voltage:
a) Check the unregulated input
voltage
at the DC INPUT jack on the MC-202. With the instrument turned on, this
will show you the voltage under a real load.
b) Check the regulated +15 volt
supply
which can be found on IC 21 pin 16, which is a Curtis Electromusic
CEM 3340 VCO chip. It was found to be approximately +15 volts.
The standard MIDIJACK installation
connects
to the regulated synth supply, usually +12 or +15 volts, but
in this case, it was found that the MC-202 was not designed to provide
the extra 35mA required by the MIDIJACK. The voltage on the +15 volt
supply begins to drop as soon as the MIDIJACK is connected, a sure
sign that it will overload it and cause damage. This is no problem,
because the MIDIJACK has a power supply that has better line and load
regulation
than the MC-202 anyway, and can operate on a much lower voltage than
the +21 volts going into the MC-202 regulator.
For this reason, we will
draw the power for our new MIDI system from the unregulated DC
IN jack. The original unregulated power voltage is too low, so we will
use a new power supply.
You must use a power supply which
is at least +12 volts DC when loaded (connected to the running
synthesizer), and a little more is better. A +14 VDC or +15 VDC power
supply with
a current rating of 300mA or higher is best. This must have a co-ax
type of power connector with an inside diameter of 2.1 mm. The center
must be -negative and the outside +positive. This is not the best
way to wire a power connector because if it is dropped on a grounded
metal
surface the outside will touch and short circuit into the ground, but
that is the way Roland did it on the MC-202. Most power supplies
you will be able to find will be wired in the opposite polarity, but it
is easy to cut the connector off and reverse the polarity for use
with the MC-202. Be careful to insulate the wires after resoldering.
This power supply is such a common type of part that you may
already have one in
your
junk box, but in the USA, a good and friendly source for this
part is Jameco Electronics. The
Jameco catalog number is 129314. It is a +14VDC@360mA AC adapter
which cost $4.95 when this article was first written in July 2001, but
had been raised to $6.95 by the time this article was expanded in 2009.
Jameco has many more that will work just as
well. The power supply used by Synhouse for this installation was
catalog number DCTX-1436 for $3.50 bought from All
Electronics. They are an equally friendly source of electronic
supplies, but their stock changes daily, and the +14VDC@360mA
supply purchased and used here has not been available for years, but
they
have others that may work just as well. When this one was used
by Synhouse, the actual voltage when loaded was +16.6 volts and the
MC-202 actually drew less than 100mA.
Obtain the correct power supply,
wire it with the correct power plug with the correct polarity, and
test it with your unmodified MC-202 before installing the MIDIJACK.
Be sure
to remove the batteries from the MC-202. It will no longer be operated
on battery power. Your new power supply will cost less than one set
of alkaline batteries and, unlike the batteries, this new power
supply will most likely last forever and won't fill up landfills with
toxic dead batteries.
9) The black and red wires must be
soldered in place to get the ground and power for the Original
MIDIJACK. The correct soldering spots are on the lower side of the
board beneath
the DC INPUT jack and POWER ON/OFF switch as seen in MC-202-pic2:
The ground wire is going to the tip
terminal
of the power jack. Solder the MIDIJACK #1 black wire to this point. The
power wire is going to the other side of the power switch so the
MIDIJACK
may be powered down with the MC-202. Solder the MIDIJACK #2 red wire
to this point. In the photo you can see the wires you are adding
are the thin ones.
10) The MIDIJACK #3 blue wire must
be connected next. You must move the top board to expose the circuitry
below on the bottom board. Do not try to unscrew it. The correct
way to do this is to use pliers from below and pinch the tips of the
nylon
standoffs to release the catches so you can push the tips through.
Later you can just press them back in place with the original snap fit.
Locate IC 18 on the main lower board of the MC-202. It is an 8-pin
chip. Look at the bottom of the PCB. Note that pins 1 and 2
are connected by the lower trace. You will leave them connected. Notice
that the solder pad and circuit trace go to the side and cross through
a via to the top. On the top the path goes off to other parts (such
as the portamento dual pot VR5, you can buzz it out to see for
yourself). This trace can be seen in MC-202-pic2a:
Cut the trace on the top side with an X-Acto knife so only
pins 1 and 2
are connected to each other but to nothing else.
One good way to cut this trace is to score two parallel grooves
and then lay a very hot
soldering
iron down on one side of the tip between the two cuts. This heat
will ruin the glue holding the center patch and delaminate it leaving
the
two sides isolated. This is often a lot less effort than digging
and digging a groove to break a circuit trace.
Photo MC-202-pic2b shows the two X-Acto cuts made:
Photo MC-202-pic2c
shows the result after
the center portion of the trace has been heated and lifted off,
exposing the paper phenolic garbage PC board underneath:
The upper lead of resistor R 234
conducts to the trace below, but
there is a problem. The problem is that these are Panasert type
resistors. These were developed by Panasonic in the early 1970s for
consumer products. They have two attributes different from other
resistors. One is that
they are preformed and precut. They are bent into a shape that allows
them to be snapped into the board before soldering in a vertical
position
which occupies less board space. Another thing about them is that
they are painted over the metal surfaces with a nonconductive paint. In
manufacturing and use, this is great, the board can be stuffed
with resistors, overstuffed to the point where the leads are touching
which is okay because they won't short circuit through the
nonconductive
paint. In repairs and modification, it is irritating, because when you
are trying to probe the board to buzz out a circuit on
a board with no silkscreen such as a Korg Synthe-Bass, you can't
tell unless you scratch the paint off of each lead. For this MC-202
R 234, you must scratch off all the paint on the upper lead of R 234
before soldering the wire onto it. Solder the MIDIJACK #6 green wire
to this point on R 234 as seen in MC-202-pic6:
14) The Original MIDIJACK will control
the MC-202's internal portamento circuit to make it think that it is
playing
a sequence programmed with portamento so that the the MIDI notes will
have
the amount of glide set by the portamento pot position. We now need
to make a simple circuit to act as the interface. Locate IC 14 on
the main board of the MC-202. It is a 14-pin chip. Find the
circuit trace from IC 14 pin 5 on the lower side of the board. Cut
the trace. This will disconnect IC 14 pin 5 from the circuit. There
will now be 3 new connections made to IC 14 pin 5. Take a new
10K resistor (a 10.2K resistor was used here) and solder one end of it
to IC 14 pin 5 and the other end to IC 14 pin 14. Do this on the
lower side of the board.
Take a new switching diode (a 1N914 or 1N4148
will work fine, one of these was included with your Original MIDIJACK
accessory packet) and connect the anode end (the end AWAY from the
little
black band) to IC 14 pin 5. Connect the cathode end of this diode
(the end WITH the little black band) to IC 8 pin 38 (this is the chip
on
the lower side of the board). This is where the IC 14 pin 5 trace
used to go. Please be very careful not to apply too much heat to
this chip.
Take another new switching diode (a 1N914 or 1N4148 will
work fine) and connect the anode end (the end AWAY from the little
black
band) to IC 14 pin 5. Connect the cathode end of this diode (the
end WITH the little black band) to a new piece of wire. You can cut
off the MIDIJACK #7 brown wire (not needed for this installation) and
use
that. Strip the insulation off the other end of the wire and twist
it until it is thin enough to insert into a via on the Original
MIDIJACK
board. A via is a place where a hole has been drilled from the top
of the board to the bottom of the board and plated through to pass the
signal between the top and bottom sides of the board.
This via you
must locate is on the top of the board 4 millimeters to the left of the
white silkscreen letters that say R 22 beneath resistor R 22. On
the bottom of the board the silkscreen says COPYRIGHT and this
particular
via goes through the "C" in COPYRIGHT, as seen in MC-202-pic6a:
Insert the new wire from the
top and solder from the bottom. Trim the excess length below.
Photo MC-202-pic6b shows the installed board with the new portamento
control wire coming out of it:
The other
end of this wire was already attached to the cathode end (the
end WITH the little black band) of the second of the two new diodes.
This will provide a control signal to turn the portamento on when the
MIDI
on mode is activated.
When all of this soldering is completed it
will look something like this setup shown in the original MC-202-pic7
from the original MC-202 article in 2001:
These leads are exposed only for the
purposes of taking this photograph, they were insulated afterward. You
must cover all of these leads with
electrical insulating tape (or heat shrink tubing if you have it
because it never becomes sticky or falls off) to prevent short circuits
once the case is squeezed
back together.
The later
installation done for this 2009 update had the metal leads covered in
miniature heat shrink tubing and the wires secured in place by potting
them with epoxy for safety, as shown in MC-202-pic7a:
Fancy!
15) The Original MIDIJACK hardware
packet contains nylon cable ties which should be used to tie the
MIDIJACK
wires into little bundles and to attach them to the factory wires
inside
the MC-202 now that all connections have been made. This will secure
the MIDIJACK wires to the inside of the chassis so they will not pop up
while you are struggling to get the case back together without wires
showing
through the slots of the sliders once the instrument is returned to
service.
16) Carefully examine all soldered
connections for possible short circuits before closing the instrument.
This will become critical when the case halves are pressed back
together.
17) Reassemble the case, making
sure that the screws are tight.
18) This installation can be
completed
in 5-10 hours. This Roland MC-202 operation is tricky, so
extra time spent making a perfect installation is time well spent.
Photo MC-202-pic7b shows the perfectly mounted DIN jack:
Performance
tips:
With the Original
MIDIJACK, the Roland MC-202 is perfect for live performance with
real-time hands-on sound tweaking of the analog synthesizer voice while
it is controlled by a MIDI sequencer. When the Original MIDIJACK
is in MIDI off mode, the MC-202 returns to normal use with the internal
sequencer and external DIN sync capabilities. The user can select
either mode at any time.
Copyright
© 4/23/2010 Synhouse Multimedia
Corporation
