I have a small alarm clock with model # alck-487 and three buttons M, S, D. i can't find the right combo of push and/ or hold to change the time. can you assist?

SOURCE: Accuwave DS Clock

The radio may not be able to get a strong enough or clear enough signal to process (night is best away from TV, computers and radios).  To regain "control" of the clock, take the battery out, wait 30 seconds and then reinstall it.  This will reset the clock.  You can then manually set the clock. 
Press SET for a few seconds until the hour starts flashing in the display.  Then press the ADJUST button to set the hour.  Press SET to move to the different functions (Hour -> Minutes -> Seconds-> Month -> Date -> Year) each time using the ADJUST button to correct the setting.  Finally press MODE to exit the setting mode.  
If the time zone is incorrect for your area (default is PST), press MODE to enter the Alarm Time Mode; then press SET to flip through the time zones; then press MODE again to exit.
The little "reset" is for use if the LCD display doesn't come on when the battery is changed. It doesn't affect any of the clock settings per se.

SOURCE: How to change the time on clock radio

I'm not 100% sure if this is right or not, but i used to have one similar and the way to reset it was:

1. Press the SET button.
   
2. After the time blinks, press the REV or FWD button to adjust the time. (Press and hold the REV or FWD button to fast reverse or fast forward time.)
   
3. To save settings press the SET button.
   
4. Once you have the clock set and have press the SET button, the time should be done blinking.

SOURCE: Magnavox CD Player Clock Radio not working

This Clock/Radio/CD player has had component failure problems. The unit is probably not worth repairing. The reason is the parts and repair information is probably very limited. The cost of the repair with parts and labor will be expensive. This repair would probably cost you more than just buying a new Clock/Radio/CD player. I hope this information helps you with your problem. Thank you for using FixYa and have a nice day!

SOURCE: I can't set the time, the alarm time, or do anything of that sort

AHAH! I had this problem also, so i tried google and it led me here. Luckily, I kept trying and figured it out so I will share my knowledge with you although you may have found it out already...
First, make sure the radio and ipod are off and it's in clock display mode.
Then, click and hold "alm set" while clicking the left "timer set" arrow to set the hour of your alarm and the right "timer set" arrow to set minutes for your alarm.
Then click "alm on/off" to turn it on and off.

SOURCE: alarm clock GE model no. 7-4894A but no manual

You can down load the manual on link below for free.

http://ec1.images-amazon.com/media/i3d/01/A/man-migrate/MANUAL000045591.pdf

Good Luck and please rate 4 thumbs up for the free answer.