The Roland D-5 was my first synthesizer and frankly…..I loved it. My first ever dabblings in multi-timbral and multi-track recording with this synth were a revelation to me. Admittedly, I don’t like many of the sounds that try to be instruments, but like any D-Series synth, it has some wonderful pads and sounds that are legendary, for example “Soundtrack”. It is a great vintage synth to keep in your collection because it is well built, lightweight, small and can be picked up for little money.

This particular D-5 had belonged to someone who regularly gigged the instrument before keeping it in a garage for 20 years. It needed a lot of attention both physically and electronically, the PCB had suffered from bad corrosion so that many ICs didn’t function anymore.

The keyboard assembly is the same basic design as the JD-800, U-20 and although it didn’t have any red glue to cause issues, it does have the dreaded flexible circuit with a thermal connection that breaks down over time, just like other more collectible synthesizers.

This article is about replacing the keyboard flexible circuit.

People ask….”Why use such a fabulous piece of expensive technology in a low value synth?!?”

It is a great synth, containing the same LA synth chip as the legendary D-50 and still looks classic Roland, in it’s aluminium black anodised case…..oh and because I can! Picking one up for circa £50 was a bargain for what it does.

There are low cost reworked flexible PCB available from us that are perfect for the D-5 and U-20, making them playable again.

Keyboard Kit Parts

The parts for the keyboard kit are shown in the picture below. It is a derivative of the Roland U-20 kit but with 8 mm spacers instead.

• 3x Spacer M3 8 mm
• 5x Self locking screw M3 x 5mm
• 1x Transition PCB P0016E
• 1x Flexible keyboard PCB P0016-03
• 1x 10 way Flat cable 300mm
• 1x 14 way Flat cable 300mm
• 1x Magnetic Label for underside

Disassembly

The D-5 is very easy to service. Gain access to the main board by removing the shielding plate and all rear panel screws. The main board can now be tilted whilst the keyboard assembly is removed via it’s 4 screws.

Unplug the keyboard flexi cable from the mainboard. The connectors are very fragile and they need careful attention. The service manual shows how they work and it is also covered in the picture below. The white flat cable shown in picture is what will be used later during reassembly.

Remove the four screws in areas shown in the pictures below to remove the keyboard assembly.

Pull the keyboard assembly free and put the rest of the enclosure to one side.

Refurbish The Keyboard

Refurbish the keyboard assembly and fit the flexible contact PCB as per Roland Keyboard Assembly Guide.  See other notes in that guide explaining how to mate the flexible PCB ZIF connector on the transition PCB.

Transition PCB

The transition PCB (Version P0016E-01) is fitted using 3 x 8 mm spacers to the end of the keyboard frame.  In the pictures below, we only had 6mm spacers so used washers for extra spacing. One spacer is only attached on one side of the transition PCB.

Note that FFC/FPC guidance text on PCB is incorrect for D-5 kit version.

The red arrows and outline show a piece of PET plastic from a box of strawberries cut to shape so that it can be a clamp and protect a vital trace on the flexible PCB. It is essential to cover this area. Especially if the plastic end cheeks are coated in conductive shielding paint (on some instruments) and could cause a short circuit.

Ensure that the two connector legs are cut flush as shown in the picture below:

Reassembly

Before fitting the plastic retaining strips to the underside of the keyboard assembly, reassemble the PCBs in the D-5 housing back in place and plug in the keyboard assembly to test.

Fit all screws holding the keyboard assembly in place, leaving the one near the bender last. Do not over-tighten these screws as the plastic has often aged and will crack under pressure. They have best left “finger tight”.

Fit the transition board in place, keeping the flat cable ends away from the nasty silicone grease on the back of the keyboard assembly. If silicone grease gets on the connection end, it must be cleaned with IPA and a cotton bud before installation in the main board connector.

Fit the flat cables into the main boards.

Re assemble loosely, without fitting the rear panel screws. the shielding plat must be fitted to prevent short circuits when testing in the next stage.

Testing

It is recommended that the keyboard assembly is fully tested before reassembling the D-5. This is because it is a huge task to reassemble in order to remove a single speck of dust or hair from a keyboard contact. It only takes a single spec of dirt on a rubber contact and velocity pick up does not work! the picture below shows the kind of dust that will cause chaos for velocity pickup.

Access test mode by the following key commands: select ROM play then hold “EXIT” and “EDIT” whilst pressing “ENTER”. Access Keyboard test by holding “A/B” whilst pressing “Bank 1”, press a key and the display in picture below appears once a key is pressed. Key and it’s velocity up or down are displayed when keys are struck. The most critical velocity parameter for consistency is “down”, it is necessary to hold the key down to see this measurement before it is replaced by “up” when released.

Confirm that each key responds and that velocity measurement is performed consistently. Please follow the test and remedy guidelines as shown in the Troubleshooting section of Roland Keyboard Assembly Guide. If velocity measurement is not working correctly, it can be remedied by cleaning the contacts again and removing dust particles. Dust makes a considerable difference to the performance, not contact flatness.

Keeping the contact assembly free of dust particles and using rubber contacts without metal coatings is critical for proper operation as it prevents switch bounce during actuation.

Final Assembly

Once successfully tested, disassemble the main board from the housing and fit the key retainer strips as per the Roland Keyboard Assembly Guide.

Refit the shield and remaining screws, carefully positioning the flat cables as shown in picture below. Take care not to trap the flat cables between pieces of metalwork. If crushed will cause a short circuit.

It is worth testing once again before putting the rear panel on, there are a lot of screws. Remember that the shortest screws are for the side cheeks, next ones up are for attachment to rear panel and M4 types are for the rest of the positions.

Copyright © 2022 Super Synth Projects, Guy Wilkinson