SY99 Floppy Disk Replacement

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SY99 Disk Drive Replacement

the original sy99 floppy disk drive with red LED

When the disk drive in my Yamaha SY99 stopped working in 2004, I ordered a replacement drive from Yamaha UK's very helpful Service Department. But installing the new drive was more than just a simple swap, and the drive came without any fitting instructions at all. What follows is how I successfuly replaced the drive......

Since I did this, supplies of the original factory part from Yamaha seem to be no longer available, and I have been receiving enquiries about alternative solutions. Here are some possible approaches that you can try (at your own risk!):

Replacing the drive belt in the original floppy drive

Suppliers of SY99 compatible slimiline floppy disk drives...

Adapting a modern floppy drive to the older type of connector used in the SY99 (for very skilled electronics technicians only!)

Here's the original 'red-LED' disk drive which refused to do anything with any floppy disk...

Note:

This is my own description of what I did with my SY99, and is shown here as an illustration of how an ex-service engineer approaches this type of task. You should only attempt this type of activity if you are suitably qualified, and confident of your ability to complete the task successfully.

These pages are not authorised or endorsed by Yamaha in any way. You should always refer any servicing enquiries to your local Yamaha Dealer, or your country's Yamaha Service Department.

		Preparation
		Upside down... Not from the Peter Gabriel song 'Downside up', but the first stage. I always put something soft underneath anything that I'm working on to protect the front panel and keyboard...
		In this case it is a yellow blanket that is full of holes that are very good at catching any screws, star washers, or other small items that might otherwise roll away and fall onto the floor. I'm also grounded via a wrist strap to avoid any problems with static. (Of course, the SY99 is unplugged from the mains electricity supply!)
		Low-cost anti-static kits are available, which are designed / intended for use when installing SIMMs, Processors or Graphics cards inside computers. Professional service engineers have workbenches with special anti-static grounded conductive rubber mats to provide protection against electrostatic discharge.

		Screws and more screws...
		Opening the SY99 There are quite a few self-tapping screws to undo to get inside the SY99. I took care to only remove the ones which hold the main metal panel in place. Some equipment has little arrows which indicate the screws to undo - but on the SY99 it was resonably obvious.
		Remove ALL the relevant screws... I found that it was very easy to miss the screws at the front by the keyboard. In this picture, you can see one on the right. The large coarse-threaded screw on the left was holding the plastic end cheek in place, and did not need to be removed. If you look carefully, you can see that the metal panel is slightly bent where I forgot to remove this vital screw the first time.
		Go easy, tiger... Self-tapping screws need to be removed (and re-inserted later) with a bit of care. In this picture, the screw is holding the metal panel onto the aluminium extrusion which forms the rear and front panel. I take my time with these: if you use too much force on this type of fastening then you can strip off flakes of aluminium which aren't good for electronics...
		Dont lose anything The lid of the cardboard box that the new drive came in is perfect as a handy storage place for all those loose screws...

		Drive extraction
		All present & correct... With ALL the relevant screws removed and placed in the box lid, I was then ready to expose the inside of the SY99. The metal plate that forms the underneath of the SY99 has to be lifted carefully upwards and away from the keyboard.
		Minimal force... As with all dis-assembly processes, I took great care not to force anything (for instance, had I forgotten to remove some of those screws on the front edge by the keyboard, then the only way that I'd be able to remove the front panel would be by unseating the screw, which would have required lots of force, and something would be bound to get broken!).
		Piece of cake... Once the plate was removed, then the disk drive was visible, and removing the three self-tapping screws that were holding it in place looked to be relatively easy.
	Click to enlarge...	Dont lose it... The screw nearest the end cheek is at the bottom of a narrow channel, and I used a screwdriver with a blob of blu-tak on the end to make sure that I didn't lose the screw. [Click on the picture for an enlarged view and more detailed description.]
		Slide it out... The disk drive front plate fits snugly into the hole in the SY99's disk bezel, and so I needed to slide the disk drive backwards towards the rear panel (towards the right in this picture) before I could lift it out.
		De-ribbon The disk drive is connected to one of the main logic board by a ribbon cable, which needed to be eased out of the socket on the main logic board. I then removed the old drive assembly...

		Debrief
		The old drive... Once removed, then I could properly see the floppy disk drive and the bracket that surrounds it. Note that the drive is fastened to the bracket with the four screws not shown here!
		Remove the bracket The floppy drive is held at the right angle to the front panel bezel with a bracket - and it is the bracket which is visible when the SY99 metal panel is removed. The drive itself is underneath the bracket and is held in place with four black self-tapping screws. The bracket is needed to hold the replacement disk drive in place, so I kept it to one side.
		Save all the bits All of the self-tapping screws that had been removed so far were now in the bits box. You wouldn't expect anything else, would you?
		The answer The floppy drive itself was now visible. When I examined it, the reason for the problem was rather obvious when I looked at the circuit board side. The synthetic rubber belt which connects the motor to the disk flywheel was very loose indeed. This is probably just the effect of age - my SY99 is from 1991, and so was about 13 years old in 2004.
		Loose belt I have read that you might be able to replace this belt with a similar belt from a cassette recorder spares kit. (See page on this topic.) In my case, I had a brand new floppy drive, so I retained this old drive as a spare for the future...

		Preparation of the new drive
		No instructions The new floppy drive was from an entirely different manufacturer, and was not a direct swap for the old one. The box that I bought from Yamaha's UK Service Department contained the drive, a bracket, a small PCB with sockets on it, some small self-tapping screws, a twin cable (black and yellow), and two ribbon cables. There were no instructions anywhere as to how to put this all together...
	Click to enlarge...	Cable connections The new floppy drive did not have very good ribbon cable keying, and I needed to look carefully to find the tiny character '1' which indicates both pin 1 and the coloured stripe on the ribbon cable. There was also the power cable (black and yellow) to connect up, but the keying on this was more obvious. [Click on the picture for an enlarged view and more detailed description.]
		Wrapping round I then wrapped the ribbon cable round the floppy drive... and turned it over...
		Remember the bracket Once turned over, I then sized up the way that the bracket would fit over the floppy drive - and particularly the ribbon.
	Click to enlarge...	Assemble the adapter board The replacement drive has a different pinout on its ribbon cable, so this tiny new board is the adapter...[Click on the picture for an enlarged view and more detailed description.]
		Watch the orientation The adapter board needs to be assembled so that the pattern on the PCB matches the hold in the little supporting bracket.
		Mounting the bracket Here is the bracket placed over the top of the new floppy drive, and the adapter board placed over the rightmost mounting holes of the adapter board. You need to make sure that the ribbon is moved across so that it will line up with the adapter board - AND so that it is not trapped by the top leftmost screw when the bracket is screwed onto the floppy drive.
	Click to enlarge...	Remember the bracket The ribbon then loops over and is plugged into the socket. The other cable is for power, and connects into the two-pin socket. [Click on the picture for an enlarged view and more detailed description.]

		Installing the new drive
		Into the bezel The complete assembly was then lowered into position and eased through the bezel hole.
	Click to enlarge...	Checking the ribbon The ribbon cable comes from underneath the floppy drive and is very close to the bottom of the bezel. I checked that all was well, and realised that this was the only possible arrangement of the ribbons. [Click on the picture for an enlarged view and more detailed description.]
		Screw into place I then screwed the new assembly into place, and connected the final piece of ribbon cable into the adapter board.
		Final ribbon The other end of the ribbon cable was then pushed into place on the main circuit board. .
	Click to enlarge...	Planning the tidy-up The replacement drive assembly was now in place and connected up. I could now think about how to tidy the ribbon cable up - all the other ribbons in the SY99 were carefully arranged with right angle flat bends produced by a single 45 degree fold, and I wanted to continue this manufacturing practice here. [Click on the picture for an enlarged view and more detailed description.]
		Tidying up the ribbon After a bit of planning, I put a deliberate 45 degree bend in the ribbon, and a 'z' bend to take up the slack as the ribbon goes to the drive adapter board.
		Screws back in place The remaining self tapping screws were then used to put the metal plate back in place. I like to start at the centre of the plate and leave all the screws loose until they are all in place. Then I start at the centre of the plate and tighten those, then work my way outwards from the centers of each of the long sides, ending up with the final screws in the centre of the end cheeks. I took care not to force the self-tapping screws - if they didn't go in easily, then I reversed the screwdriver and tried again until I found a thread starting position that went in smoothly and easily.
		Empty box lid Theoretically, the box lid at this point should be empty. Luckily, when I looked, it didn't look like this!
		Verify and test All done! All that remained now was to check that the drive works by formatting a blank floppy disk and doing a 'Save All' followed by a test load of a sequencer file. Everything worked! Mission Accomplished. My only niggle is the green LED which replaces the previous red one, but I'm sure I will get used to it.

		Mission Complete!
		I hope that you have found this description interesting. I've tried to expose all of the things that go on in my head whilst I am tackling this type of task, in the hope that this information is useful in revealing my approach, methods and way of thinking.

Note:

These pages are not authorised or endorsed by Yamaha in any way. You should always refer any servicing enquiries to your local Yamaha Dealer, or your country's Yamaha Service Department.

SY99 Disk