Kurzweil digital piano unpredictable voices and volume

If certain notes on your Technics SX-PR150 digital piano are playing at a lower volume than others, it's possible that there could be a few underlying reasons for this issue. Here are some steps you can take to troubleshoot and potentially resolve the problem:

1. Dust and Debris:
   • Check if there is any dust, debris, or foreign objects present around the keys and internal components. Dust or debris could affect the key's action and cause uneven volume levels.
2. Contact Cleaning:
   • If you're comfortable doing so, you can carefully open the piano and clean the contacts underneath the affected keys. Contacts that have accumulated dirt or oxidation might lead to volume inconsistencies. Use a clean, dry cloth or contact cleaner specifically designed for electronics.
3. Key Mechanism:
   • Inspect the key mechanism for any signs of physical damage, misalignment, or wear. Damaged or misaligned keys could lead to uneven volume levels.
4. Sensors and Sensors Board:
   • Digital pianos like the Technics SX-PR150 use sensors to detect key presses and control volume. If a sensor is malfunctioning or damaged, it could result in volume inconsistencies. Check the sensors and their connections for any issues.
5. Audio Output and Amplification:
   • Check if the issue is specific to the internal speakers or if it also occurs when using headphones or external amplification. If the issue is present across all audio outputs, it might be related to the piano's internal components.
6. Factory Reset:
   • Perform a factory reset on the piano to restore its settings to default. This can help rule out any software-related issues that might be affecting the volume levels.
7. Professional Inspection:
   • If the above steps do not resolve the issue, it's recommended to seek the assistance of a professional technician who is experienced in repairing digital pianos. They can diagnose the problem accurately and perform any necessary repairs.

Please exercise caution while performing any internal inspections or repairs on your digital piano, especially if you're not experienced in working with electronic equipment. If you're unsure or uncomfortable with the process, it's best to seek professional help to avoid causing further damage.

Your piano was manufactured sometime between 1925 - 1930. As far as I can discern, it cannot be pinned down any more specifically than that, nor can it be determined where it was constructed. Sorry. . .

Hard reset procedure

1. Turn the Kurzweil off
2. Hold down the KEY START, KEY STOP, and LAYER VOLUME buttons for 5 seconds while powering the unit up, then release
3. Select RUN DIAGS
4. Press the UP arrow until the display reads RAM TEST
5. Press the START/STOP button to run the test
6. When the display reads SUCCESS, turn the unit off and back on. The unit is now reset.
If your Kurzweil still does not come up to the normal screen after this procedure, it will require service.

Try to re-initialize the unit(factory reset). If the keys are the problem then the rubber key contacts need to be cleaned or replaced. Contact a local service center for help.

The place to get the best help for Kurzweil gear is Sweetwater Sound.
Other than that, always use it in stereo mode with a decent sound system. Always use speakers with at least a 15" woofer and a horn to get the full range of sound it's capable of.

The Kurzweil SP3X is a popular stage piano known for its high-quality sound, responsive keyboard, and versatile features. Some of the advantages of the SP3X include its excellent sound quality, which is achieved through Kurzweil's advanced sound engine and a variety of realistic instrument sounds. It also has a highly responsive keyboard that is suitable for playing a wide range of musical styles. Additionally, the SP3X has a variety of features that make it a versatile and useful instrument for live performances, such as its built-in sequencer, arpeggiator, and various effects. Overall, the Kurzweil SP3X is a reliable and powerful stage piano that is well-suited for both professional and amateur musicians.

It sounds like there may be an issue with the piano sounds on your Kurzweil sp4-7 keyboard. One possibility is that there may be a problem with the software or firmware of the keyboard, in which case you may need to update the software or contact the manufacturer for assistance. Another possibility is that there may be a problem with the internal hardware of the keyboard, in which case you may need to have it repaired by a professional technician. In either case.

You may not have the patience level to attack it. Few ppeople do.

Search Ebay completed items for same model or similar to see what they sell for at auction.

I don't see you doing any damage by having a look but I would get a piano tuner or repairer in to investigate the problem expertly - no slight on you. But if your Church congregation depend on it it's well worth the money.
Good Luck