One of the keys catches/stops about 1/2 way down. It can be pushed all the way down with effort. Sound occurs when it is pushed all the way down, but it is muted somewhat

6. Playback
(1) Set channel 1 to play.Turn the REC/PLAY key on. Then press the channel key of track 1 (the track you just recorded) to set it to Play (key lit green).
(2) Return to the beginning of the song.Hold down the STOP key and press the REW key to return to the beginning of the song (?p.37 "2. Location").

Yamaha's have little rubber "contact strips" that run under the keys. These strips have little rubber buttons on them, exactly like your tv remote. When you push the key down, it pushed the rubber button down and make an electrical contact. These buttons eventually fail and separate where the bottom of the button meets the strip. You have to replace the strip (different sizes, depending on where on the keyboard it is) but they aren't cheap. You can find them here http://syntaur.com/yamaha_psr.html but sometimes you can find someone selling them on ebay cheaper. If you only need a single strip, or maybe two, it's probabaly worth it. More strips than that and you may find it cheaper to buy someone's broken keyboard on ebay and take the strips out, especially if it's broken for a different reason, like won't power up.

Hi, If by "re" not working you mean note D then try the following.
Keyboard off, hold down top C key while turning on. This factory resets. Does D key now work - if not. Has it ever worked - if not then it could possibly be the ribbon connector between the keyboard and the motherboard. If one of the cables gets bent then this would stop all notes associated with that connection to stop working. This will only have occured if the keyboard has never played these notes or if it has been taken apart.

You could also try the self test mode : Keyboard off, hold C#,F, G# in the 2nd octave up whilst turning on, cycle through tests to sound if it plays all the notes one at a time then the sound chip is ok and it points to keyboard switching. If test mode does not come up in 2nd octave try 3rd octave ( cant remember which one it is from memory )

Let me know how you get on.

Resetting Instructions:
1) Try a partial reset by holding down the last white key while turning the unit ON.
2) If you haven't recorded any performance(s), for a full reset, hold down on the last white key AND THE lst three black keys while turning the unit ON.

DUST on sensors! If you have steady hand, you can remove the entire keyboard. Using a computer vacuum cleaner, clean the sensors on the instrument, then replace the keyboard carefully. Or, take it to a technician to have the keyboard sensors cleaned.

Do an initialization (factory reset) by holding the HIGHEST WHITE key down and turning on the power. Hold the key for an extended time until display confirms initialization complete. This will restore unit to factory defaults.

Had a similar problem with Yamaha P-250, which had been dropped, causing a small PCB (which was held to the Motherboard via a small edge-connector) to come out of the connector slightly & thus give poor contact.

Pushing the connector back restored normal operation.

If this advice is helpful, a FixYa rating is a great reward for my efforts to help you. Cheers.

Hello I have this pedal too and have experienced similar problems..
If you are using battery power only use Duracell Ultra (or equivalent) never re-chargeable batteries. However I am assuming you are using the mains power adapter rather than batteries.
Start by eliminating external issues. Change your guitar lead and output lead - if you don't have spares swap them over or swap the ends round to make sure it is not a contact issue in the jack sockets.
I found this problem occurred most often when I was using headphones plugged directly into the pedal rather than an amp. I was usually able to solve it by wiggling the output jack plug slightly so came to the conclusion that it was just a poor quality plug or socket.
Having said that I think that there might be a bug in the processor unit itself because I have occasionally experienced the problem when playing through an amp. I resolved it by unplugging everything and starting again but this is a bit annoying either during a gig or half way through a recording session.
Does it do it on every patch or only on some? I have one patch that is completely clean (straight through) with no effects, noise reduction, boost, with the tone set at flat. You could try setting a patch like that up as a comparison and see if it still does it.
Lastly you could try recalibrating the expression pedal.

1. Unplug the input jack to turn the unit off.
2. Hold down the pedal assign button whilst plugging the input jack back in.
3. The display should read 'dn'
4. Raise the pedal fully and press the store key
5. The display now reads 'UP'
6. Push the pedal fully down to the stop and then release it (it will return slightly)
7. Press the store key again
8. Job done (unless the display reads 'Er' - in which case repeat from step 4)
9. 
   

Wild guess of possibilities.

1. Internal backup battery exhausted.

2. Button OR key is stuck down, either mechanically or electrically.

I'm sorry but it sounds like you will have to have it repaired professionally.