Before the steps the typical warning. DO THIS ONLY IF YOU HAVE BASIC ELECTRONIC KNOWLEDGE, MEDIUM SOLDERING SKILLS AND A MULTIMETER. DO THIS AT YOUR OWN RISK. MAYBE THERE ARE DIFFERENT PCB VERSIONS, CAREFULLY FOLLOW THE RECOMENDATIONS IF YOUR R3 IS NOT EXACTLY AS THIS.
Despite of this warning, if you are meticulous that's all what you need.
1º After you unscrew all bottom case's screws and remove it you'll have this. You can see the right PCB (audio PCB) and the left PCB (digital PCB) covered with the aluminium paper. Underneath both is the front panel PCB.
2º Remove all the back panel's screws, the three aluminium paper's screws and the two digital PCB's screws.
3º Remove the audio PCB after removing all its connectors (in my case all the connectors are different so there's no chance to make a mistake when connect them back, but take precautions if yours is different).
4º You'll see the tempo potentiometer's pins and a seven pin connector to its left in the front panel's PCB. The tempo pot's medium pin is connected to it (most left pin of the connector). Check if this is true with your multimeter.
5º In the digital PCB there is an analog muxer/demuxer chip (LW052A). The tempo potentiometer's medium pin is connected to its pin nº1 through the seven pin connector. Check if this is true with your multimeter.
6º The tempo pot's signal comes out from the pin nº3 of this chip and it's connected to one pin of a 100 Ohm smd resistor (check this with your multimeter). The other pin is connected to the big square main chip.
7º Solder one capacitor's leg to the resistance's pin which is connected to the main chip, and the other leg must be soldered to ground. In this case there is a ground near the main chip, just scratch it with a knife and solder it to it. If your PCB is different look for a ground (often it's a thick trace, your multimeter will be helpful).
8º You're done!
Please if you do it post your results. Good Luck.
Hugo.
