Digital clock in 88CD model does not keep accurate time

To set the time on a Sterling and Noble chiming clock, please follow these steps:

Remove the clock from the wall or mantle and place it on a flat surface.
Locate the clock's time adjustment knob. This is usually located on the back of the clock and may be labeled "Time," "Adjust," or "Set."
Turn the knob clockwise or counterclockwise to set the correct time. Be sure to move the hands of the clock in the direction of the correct time.
If your clock has a chime feature, locate the chime adjustment knob. This may also be located on the back of the clock and may be labeled "Chime," "Strike," or "Silent."
Turn the chime adjustment knob to the "Silent" position if you do not want the clock to chime. If you want the clock to chime, turn the knob to the desired chime setting.
Once you have set the time and chime settings, replace the clock on the wall or mantle.
Note: It is important to set the time accurately and synchronize it with an accurate time source, such as an atomic clock, to ensure that the clock keeps accurate time. Additionally, it is recommended to consult the clock's user manual for specific instructions and troubleshooting tips.

Most likely its the digital display is burnin out, If your farmilar with electronics and soldering, you can just order the part and replace it yourself. If not shop around for a cheaper rrepair technician in your area.

Normally there is an adjustment available. /contact the manufacturer.

A couple of possibilities- If there is no fuse holder on the rear of the box, it may not be user-replaceable but soldered onto an internal board. If it has blown, either there has been a component failure in the power supply that caused the fuse to fail or the supply is not starting up as it should, a problem caused by cheap capacitors in certain areas of the supply. Unless you have at least a multimeter, this is not a good choice as a DIY repair.

I don't believe you will find the Service Manuals generally available online. You would likely need to obtain these from a technician working in an authorized dealer location. If nonone has been able to respond to your request at this point I would recommend you contact Cambridge Soundworks directly to see if they can and are willing to provide. Their contact information can be found here:

http://store.cambridgesoundworks.com/content/about_contact.htm

For independent operation, the clock is connected to a reliable source of 120 VAC 60HZ (or 230 VAC 50HZ), and time is maintained with a real time clock chip. Switches located on the front of the clock allow for easy and accurate time setting. For system clock applications, synchronization can be accomplished by connection to Simplex BCD digital data for instantaneous time updates. Clocks can also be connected to power line carrier/synchronous timing inputs that provide hourly and 12 hour corrections. Impulse correction from the 6400 Series Master Clock is ideally suited for Time and Attendance System expansions. A capacitor in each clock maintains timekeeping for approximately 12 hours in the event of power failure in the facility. The Celestra 2000 can be corrected with six different clock codes to suit any specific retrofit or new synchronized time system.

I can't find a manual for this but my guess would be there is a setting for the Display to dim it at all times unless you touch a control.

it could be possible you can try on ebay and see if someone is selling there old one

OK now you sized it down the ignition on it lights the numbers but the unit needs the power from the battery and that has to be seperate and direct wirh some type of fused protection. Just like if you had the battery out or dead everything resets to its origin.
Always had to reboot a computer in the old days... Now a days it is our cars Tommy Tech the Wreck

They say to hold the button for 14 seconds or til it beeps, for it to stay on.