Reset the keyboard to factory). This will eliminate any "setting" issues that may have been accidentally altered and causing the issue.
From the manual (page 18):
Resetting the User Memory to the Initial Factory Settings The original factory settings of this synthesizer’s User Memory can be restored as follows. NOTE When connecting a computer to the MOTIF XF via a IEEE1394 cable, disable the driver used for this connection beforehand, and follow the procedure below to execute Factory Set. NOTICE When the factory settings are restored, all the Voice, Performance, Song, Pattern, and system settings in the Utility mode you created will be erased. Make sure you are not overwriting any important data. Be sure to save all important data to your USB storage device or a computer on the network before executing this procedure (page 64). 1 Press the [UTILITY] button then the [JOB] button to call up the Factory Set display. 2 Set the check box of “All” to on, then press the [ENTER] button. The display prompts you for confirmation. Press the [DEC/NO] button to cancel the Load operation. 3 Press the [INC/YES] button to execute the Factory Set. After the Factory Set has been completed, a “Completed” message appears and operation returns to the original display. NOTICE • For Factory Set operations that take longer to process, you will see the message “Now executing Factory Set…” during processing. While such a message is shown on the display, never attempt to turn off the power while data is being written to Flash ROM. Turning the power off in this state results in loss of all user data and may cause the system to freeze (due to corruption of data in the Flash ROM). This means that this synthesizer may not be able to start up properly, even when turning the power on next time. • When entering a checkmark to the box of the Power On Auto Factory Set and executing the Factory Set, the Factory Set will automatically be executed each time turning the power on. Keep in mind that this also means that your original data in Flash ROM will be erased each time you turn on the power. Therefore, the checkmark of this box should normally be removed. If you remove the checkmark of this box and execute the Factory Set, the Factory Set will not be executed when turning the power on next time. For details about the Factory Set, refer to “Resetting the User Memory to the Initial Factory Settings—[JOB] (Factory Set)” in the Reference Manual.
page 68 of the manual:
No sound?
Wrong sound? When a problem like this occurs, please check the following points before assuming that the product is faulty. You may solve your problem by executing the Factory Set (page 18) after backing up your data to an external storage device. If the problem persists, consult your Yamaha dealer. No Sound. Are all eight sliders set to appropriate levels (other than zero or minimum)? Is the MOTIF XF properly connected to related external equipment (e.g., amplifier, speaker, headphone) via audio cables? Since the MOTIF XF has no built-in speakers, you will need an external audio system or a set of stereo headphones to properly monitor it. Check the Local Control parameter and the FW Monitor Setup parameter in the Utility mode. When the MOTIF XF is used by itself and the Local Control parameter is set to off or the FW Monitor Setup parameter is set to “with PC,” no sound is produced even if you play the keyboard. Is the power of this synthesizer and any external equipment connected to this synthesizer turned on? Have you made all the appropriate level settings—including the Master Volume on this synthesizer and the volume settings on any connected external equipment? Is the Foot Controller pressed down (when it is connected to the FOOT CONTROLLER jack)? Are the MIDI volume or MIDI expression settings too low when using the external controller? Is this synthesizer properly connected to related external equipment (e.g., amplifier or speaker) via audio cables? Are the effect and filter settings appropriate? If you are using the filter, try changing the cutoff frequency. Some cutoff settings may filter out all of the sound. Are the volume or expression settings too low? Are the parameter settings such as Element Switch, Part Switch, Note Limit and Velocity Limit appropriate? When the Element to which “Legato” of the XA Control parameter is assigned does not sound, is the Mono/Poly parameter of the Element set to “Mono”? Or, is a value other than “Legato” of the XA Control parameter assigned to another Element within an Element Group? Troubleshooting [UTILITY] [F5] Control [SF2] MIDI Switch Local Control [UTILITY] [F2] I/O FW Monitor Setup [VOICE] [EDIT] [COMMON EDIT] [F6] Effect [PERFORM] [EDIT] [COMMON EDIT] [F5] Effect [SONG]/[PATTERN] [MIXING] [F5] Effect [VOICE] [EDIT] Element/Key selection [F3] Filter [PERFORM] [EDIT] Part selection [F4] EG Filter [SONG]/[PATTERN] [MIXING] [EDIT] Part selection [F4] EG Filter [PERFORM]/[SONG]/[PATTERN] [SEQ SETUP] [F2] MIDI Filter [UTILITY] [F1] General [SF1] Play Volume [VOICE] [EDIT] [COMMON EDIT] [F1] General [SF2] Play Mode Volume [VOICE] [EDIT] Element/Key selection [F4] Amplitude [SF1] Level/Pan Level [PERFORM] [EDIT] [COMMON EDIT] [F2] Level/MEF [SF1] Level Volume [PERFORM] [EDIT] Part selection [F1] Voice [SF1] Voice Volume [SONG]/[PATTERN] [MIXING] [F1] Part 1-16 Volume [VOICE] [EDIT] Element/Key selection [F1] Oscillator [PERFORM] [F2] Voice [PERFORM] [EDIT] Part selection [F1] Voice [SF1] Voice Part Switch [VOICE] [F2] Porta Mono/Poly Mode = mono [VOICE] [EDIT] Element selection [F1] Oscillator XA Control [VOICE] [EDIT] Element selection [F1] Oscillator Element Group MOTIF XF Owner’s Manual 69 Troubleshooting When the Element to which “Key Off Sound” of the XA Control parameter is assigned does not sound, are you releasing the note after the AEG decays? The “Key Off Sound” Element will take over the AEG level of the previous Element if both the Elements belong to the same Element Group. To solve such a problem, release the note before the AEG level decays to minimum or set the “Key Off Sound” Element to a different Element Group from the previous Elements. When the Element to which “AF1 on,” “AF2 on,” or “all AF off” of the XA Control parameter is assigned does not sound, is the corresponding ASSIGNABLE FUNCTION button pressed? Is “Vocoder” selected as the Insertion Effect Type of the Voice? If so, set the parameters related to the AD Part and A/D INPUT connector to the appropriate values then play the keyboard while inputting your voice into the microphone connected to the MOTIF XF. Check whether or not the Gain Knob on the rear panel is set to the minimum position. For details, see page 47. When playing the keyboard in the Performance/Song/Pattern mode produces no sound, has a Voice been properly assigned to each Part? When Song/Pattern playback produces no sound, are the output channel of each track in the play mode and the receive channel of each Part in the Mixing mode set appropriately? When Song/Pattern playback produces no sound, are the Velocity Rate and Velocity Offset settings of the Play FX appropriate? No sound is produced when the ARP Play Only parameter is set to on and one of the following situations occurs. • When the [ARPEGGIO ON/OFF] button is turned off. • When the ARP Switch parameter of the corresponding Part is set to off. • When no Arpeggio Type is assigned to the current Voice.
