SH-09 Analog User Modifications

The following plans describe a method of adding MIDI capability to the Roland SH-09 analog synthesizer with the Synhouse Original MIDIJACK. The SH-09 is especially well suited for this modification due to the tiny size of the MIDIJACK circuit board. 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, you can ship the unit to Synhouse L.A. for a quick, low cost Factory Installation.

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 installation on which this document is based was on Roland SH-09 serial #044691, 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!

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, strong wire cutters or other flush cut nippers, a hobby knife such as an X-Acto, scissors, a soldering iron, solder, and electrical insulating tape. A Dremel Moto-Tool or hot knife will be useful if you wish to carve out the inner portion of the left side plastic end cap to accommodate the MIDIJACK board, as shown in this example by Synhouse. If you intend to mount the DIN jack on the back panel with the rest of the jacks, you will need to use a chassis punch (a small hand tool that safely cuts a clean hole in a metal panel) or step drill (a cone-shaped drill bit with many steps on it from small to large) to make the hole for the DIN jack, and an 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, and also a 1/4" or 5/16" drill bit to make a pilot hole to start the chassis punch. The correct size for mounting a MIDI DIN jack is 14.5 mm metric or 5/8" SAE (.62"/15.9 mm) in American sizes. A chassis punch may be purchased from any good tool or hardware store. If it is more convenient, a punch may be mail ordered via internet or telephone from Mouser Electronics at http://www.mouser.com or (800) 346-6873. The Mouser part number is 586-3803 for the name-brand Greenlee 730-5/8 (about $30). The cheaper house brand part number is 380-0145 (less than $20). You will also need an 11 mm wrench (for Greenlee) or 1/2" wrench (for the Mouser house brand punch) or adjustable wrench to turn the chassis punch while cutting the hole. An automatic center punch would also be useful. This is an inexpensive spring-loaded pointed punch that can mark your drilling spot without the use of a hammer. Marking the holes with this small indentation will allow you to drill cleanly without slipping and scratching the synthesizer or drilling through your knee.

Always wear eye protection such as safety glasses when working with power tools, cutting tools, or punching tools.

The board and DIN jack can be mounted in the metal as shown in this example done by Synhouse, which requires a drill and a chassis punch, or the entire assembly can be done in the plastic end caps using only a hobby knife, with no drill or chassis punch required.

2) Fully test the Roland SH-09 to be converted to MIDI. Be sure that all functions such as VCF envelope work and that the instrument plays in tune while playing along with a known well-tuned instrument such as a newer digital synthesizer or sampler keyboard. If it doesn't work properly without MIDI, it certainly won't work with it.

3) The installation of the MIDIJACK in a Roland SH-09 is fairly simple, as long as you follow these instructions closely. All of the electronic work can be done on two boards without removing them. The Roland SH-09 has jacks soldered directly into the PC board and the safest way to access the signals without compromising the strength of the factory solder joints is to leave them just as they are and cut a tiny notch in the copper circuit trace a short distance away from the jack itself. This modification reroutes the local keyboard signals through the computer-controlled analog switching matrix of the MIDIJACK by extracting the signal and inserting the users' choice of local keyboard control or MIDI.

4) Extreme caution should be taken while working on the Roland SH-09. The unit should be unplugged while open and even then, the power supply may pose some electric shock hazard due to residual voltage in the power supply.

5) The entire synthesizer and interface jacks are mounted on three boards which are bolted like a PC board sandwich to the underside of the slider control panel. To make your life easier and do the installation quickly, completely remove this assembly as one unit. Remove the three Phillips screws on the lower edge of the rear side, and remove the three Phillips screws on each end of the control panel that are holding it onto the plastic end caps. They are on the bottom panel, two on the right edge, two on the left.

6) Open the case slightly and locate the green wire that serves as a ground strap, which ends in a terminal attached by a screw to the rear right corner of the base. Remove this screw to release the wire. Slightly separate the two halves of the instrument, which will still be connected by wires. Turn the synthesizer upside down and shake out any dust and debris that may have accumulated inside the instrument over the years. If required, the two plastic end caps may be removed by removing three Phillips screws on each end of the underside of the base, and note that each one has an extra screw to be removed approximately one inch in from the others. Remove anything else that may be holding the end caps in place. This should be done with extreme caution, as the the end caps are very fragile and possibly already broken.

7) Before unplugging any wires, look at them very carefully, and note their positions before removing any of them. There is a power supply in the base of the instrument that provides ground via two bundles of black wires and supplies a regulated +/-15 volts DC. There are two bundles of red wires that provide +15v, and two bundles of blue wires that provide -15v. BEWARE OF THE CONNECTOR POLARITY! At first glance, it may appear that there are a series of identical 3-pin connectors that supply +/-15v to various modules of the synthesizer. This is NOT the case. Some are wired backwards, and reconnecting them the wrong way would certainly destroy some of the circuits. A good way to mark them is to use a marking pen such as a Sharpie to make a random slash mark or two or three across both halves of the connectors, a little differently on each, so that you can see if they are reconnected properly later on.

8) The wires with white connectors have a snap lock holding them in place. To release the lock, insert a small screwdriver and pry it open as shown in SH-09-pic1:

9) The wires on the end are held in place by a black connector which has a snap lock holding it in place. To release the lock, press the tabs inward with the screwdriver as shown in SH-09-pic2:

10) The upper panel/synth assembly should be free of the base now. All electronic work can be done by connecting the MIDIJACK wires to the main board and jack board.

11) For this demonstration unit done by Synhouse, considerable effort was made to keep all MIDIJACK controls on the synth control panel, visible at all times, in a way that would look the most like something done at the factory. This meant putting the MIDIJACK board at the far left of the control panel, just to the left of the MODULATOR section, and the DIN jack on the rear panel, just to the right of the D in ROLAND. This required three special accommodations to be made. The left end cap of the SH-09 was hollowed out inside to allow space for the MIDIJACK board, and the rear of the board was insulated with electrical tape to prevent a short circuit against the metal frame right next to it. The main synth board was temporarily lifted an inch out of place to make room for the chassis punch and wrench while cutting the hole for the DIN jack.

12) Determine the place where the MIDIJACK circuit board will be mounted and test fit the board into its' correct place inside the case. The easiest place would be on the underside or in the plastic end caps, which would not require a drill or chassis punch. Mark the correct mounting holes on the front panel with a pencil, marker, or needle using the paper drilling template provided with the MIDIJACK hardware packet as seen in this photo called SH-09-pic3 which shows the paper drilling template taped in place:

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". Much care should be taken not to break the synth boards. Instead of using the thick, double sided, plated through hole, FR4 fiberglass epoxy circuit board type used by Synhouse for the MIDIJACK, Roland used a brown paper phenolic single sided PC board. You couldn't find a worse board if you tried. Many (now) popular instruments such as the Roland Juno-106 have problems or do not work at all, due to cracked circuit boards that could have been caused only by flexing the chassis across the length of it. To avoid damage while drilling, one side of the panel can be supported by a vise where the jaws have been covered with old denim to prevent scratching, as shown in SH-09-pic4:

Drill the holes. A photo called SH-09-pic5 shows the location of the newly drilled mounting holes:

13) Mount the MIDIJACK board in place. When mounting the MIDIJACK board, the switch should be fitted so well in the panel that the switch stem will not wiggle at all once in place. It should not have any free play but also should not be so tight that it binds. When the switch is pressed, it should have a definitive "click" and bounce back like the button on a new VCR. You will never regret spending too much time on this and good attention to detail will make the perfect MIDIJACK installation. The hole in the panel that is over the MIDIJACK scale adjust trimpot should be large enough so a Synhouse Pocket Screwdriver can fit through the panel for periodic adjustment. The perfect MIDI control panel installation is shown in SH-09-pic6:

Photo SH-09-pic7 shows the underside and the insulating tape applied to it to prevent shorting in this tight space:

If the board is installed in this manner, a Dremel Moto-Tool can be used to carve out the inside of the left end cap to allow space for it, as shown in SH-09-pic8:

Always wear eye protection such as safety glasses when working with power tools, cutting tools, or punching tools. When finished, it should look something like the one shown in SH-09-pic9:

14) Determine the place that the MIDI input DIN jack will be mounted. In this example, it was mounted on the rear panel, just to the right of the D in ROLAND. To do this, the main synth board was temporarily lifted an inch out of place to make room for the chassis punch and wrench while cutting the hole for the DIN jack. The PC board is held in place by snap lock nylon standoffs that can be released by pinching the ends with needlenose pliers. To avoid this extra work, the DIN jack could be mounted anywhere else on the instrument. Use the paper template to mark the correct spots to drill and cut as shown in SH-09-pic10:

If mounting in metal, it is advisable to use a chassis punch to make the hole for the DIN jack. Remember that the DIN jack is to be mounted with the smaller 4-40 hardware size rather than the larger 6-32 size that secures the main board. Drill two holes for the screws then drill a slightly larger hole in the center to act as a pilot hole for the chassis punch. Use the chassis punch to cut the hole and be sure that the wrench is turning the tool from inside the synth, not outside, so the cutting edge is coming from the outside. This will ensure that the outer edge is perfectly smooth. The properly cut mounting holes may be seen in SH-09-pic11:

15) The MIDIJACK #1 black and #2 red wires must be soldered in place to get the ground and power for the MIDIJACK. Examine the center sections of the synth board closely. There is a wire jumper with the proper ground, located one inch from the +15v power pin marked "79". Solder the MIDIJACK #1 black wire to this point as shown in SH-09-pic13:

There is a wire jumper with the proper regulated +15v power, located three inches from the +15v power pin marked "79". It is in the section marked "H.P AMP", very near the marking "7". Solder the MIDIJACK #2 red wire to this point as shown in SH-09-pic14:

16) Examine the jack board PCB with the CV/gate jacks on it. All MIDIJACK I/O connections can be made on this jack board. It can best be done without removing it. Leaving it bolted in place, you must cut two PCB traces and solder four wires in place, one on each side of each cut trace. Before modification, the jack board is as shown in SH-09-pic15:

Locate the proper cutting and soldering points. Two traces will be cut and four MIDIJACK wires will be soldered to the exposed (bottom) foil side of this board. Photo SH-09-pic16 shows the jack board with the two trace cuts made:

A look at this will give some idea of what it will look like when done correctly. The jack board should be placed foil side up on the work surface with the upside down jacks pointing toward you, the same position shown in the photo. These are the traces coming from the tip of the 1/4" plugs inserted into the CV/gate input jacks, and they also carry the local SH-09 keyboard signal from the switched input to the jack. Carefully cut the traces with an X-Acto knife. One good way to do this 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 wide enough to break a circuit trace. Solder the MIDIJACK #3 blue wire, MIDIJACK #4 white wire, MIDIJACK #5 yellow wire, and MIDIJACK #6 green wire to the board as can be seen in SH-09-pic17:

17) Carefully examine all cuts and connections made to the jack board for mistakes or possible short circuits. Make sure that there are no foil pieces or solder bits left hanging around to cause a short circuit later on. The CV and gate terminals are now isolated and routed through the MIDIJACK.

18) The MIDIJACK #7 brown wire and #8 violet wire (unless it is used for a special function as described in the Advanced Installation Manual) are not required for adding MIDI to the Roland SH-09, but it is a good idea not to permanently cut these wires off, as an alternate installation method may become useful later. It is best to wrap the ends of these unused wires with heat shrink tubing or electrical insulating tape and bundle them with the other wires.

19) Use the small cable ties provided with the MIDIJACK to bundle the excess wires and hold them in place as shown in SH-09-pic18:

21) It is time to reassemble the Roland SH-09 as it was before. Be sure to properly reconnect each connector that was removed, then put the pieces back together with the screws, and close the chassis halves and secure with screws on the upper and lower sides. As done by Synhouse, the new MIDI control panel appeared as shown in SH-09-pic19:

22) Test and calibrate using the procedures described in the Original MIDIJACK Installation Manual. This installation can be completed in as little as one hour, but extra time spent making a perfect installation is time well spent.