Optical Output for Sony MDS-S50

[henry's cat]

Both the Sony MDS-S50 and MDS-JE640 share the same pattern of main printed circuit board (PCB). The more expensive MDS-JE640 has a coaxial input, two optical inputs and an optical output. With the addition of three components an optical output can be added to the MDS-S50.

The main PCB in the MDS-S50 has all the mounting holes for the optical transmitter but two capacitors, C661 and C662, and a miniature inductor, L661 are missing. Both models use the same Digital Signal Processor chip (IC151) and the digital output from pin 21 is routed through to the rear panel on the PCB.

The most difficult part of this modification is creating the hole in the rear panel for the transmitter and you need to be fairly good at soldering. Be careful when removing the PCB as there are some delicate wire flats that need disconnecting. The board is populated with surface-mount technology (SMT) components but none are needed for this modification.

You will need a Sharp Toslink GP1FAV31TK0F fibre optic transmitter (Radio Spares part no. 6666491), a 4.7 microfarad 16V (C662) capacitor and a 0.1 microfarad polyester cap (C661). The transmitter fits into the space labelled IC661 at the rear of the main PCB. The rear panel cutout dimensions required for the Toslink transmitter and the fixing screw hole height above the PCB are the same as the existing receiver. You can find the height of the required cutout by drawing lines across from top and bottom of the existing hole for the optical receiver. The centre of the cutout can be found by placing the transmitter onto the board and passing a fine drill bit through the mounting hole from the rear and giving it a few turns to leave a mark on the bare metal as to where to drill a hole for the mounting screw. Drill the hole and then mark a line down from it to cross the lines for the top and bottom of the cutout.

C661 is an SMT device so you can't solder a standard capacitor onto the tiny pads. Instead, place C662 on the topside of the board and pass the leads through then bend and trim the leads of C661and pass them through the same holes from the underside of the board so it lays flat and solder both in place.

L661 is a tiny SMT inductor that supplies 3.3V to the transmitter but in this case can be replaced with a tiny wire link shorting the solder pads together. Just take a thin piece of tinned copper wire and bend a short section at one end at a right angle. Carefully solder it in place and then trim off the excess.

The service manuals with circuit diagrams and PCB layout are both available from the minidisc.org website which is where I got the idea from.

[sfbp]

Neat.

Did you see the posts,. by Camron Crouse about adding optiout to the MXD-D5C, and my own about same for the MXD-D40? The "big" problem has often been that the 3.3V parts are unobtainable. I'm amazed you got one. However we discovered that it's actually much easier if you use the 5V diodes made by Toshiba, as in most cases 5V is easily found on the main board - typically for the PS/2 connector. Would appreciate a URL for the 3.3V part, though. I used a 3.3V part; in retrospect it would have been easier not to bother, as it was used and came from very far away (England).

I have a JE640. What would be really neat would be to add PCLink to the 640. I never even noticed this MDS-S50 model on the list of decks, as having the PCLK connector. What I have not yet figured out is why Sony makes slight variations in that "keyboard" connector (well, the electronics behind it), even between different country versions of the same machine. For example the MDS-JB940 has a keyboard connector, and it is alleged to be a PCLink socket too, and the circuit diagram seems to show that. But no one yet has reported it working, only that it does not work as an MCrew device.

Maybe we need a section on hardware hacking (there's one at minidisc.org but we don't have write access to that)?

Added: Holy Cow! They're here for 0.72 Euros - and I couldn't find any in N. America.