6. Can not coin, a few coins:
Check the SSR drive circuit U5 (75452); and then check the U7 (8051) the fourth foot to see whether it has a signal in the coin output, the number of coins U7 (8051) seventh foot, the signal should be back coins.
7. Coin not allowed or coin no show:
First check U18 (PC817) is normal; and then check U23 (8279) sixth foot when there is no signal input coin or replace U23 (8279) a try.
8. Keyboard does not move:
Check the output and input of U24 (2003) first; then check U25 (4028) output and input, and then check U23 (8279).
9. Unable to retain:
Check U8 (6116); and then check U1 (74HC00), battery charging circuit, turn off the power after the battery voltage is measured whether the normal 3.6V.
10. Seven-segment display error:
If there is only one set of display faults, simply replace the faulty one, or check U26 (2003). If all errors (eg all have a draw off), check U27, U28 (4028) And U23 (8279) of the foot of the signal.
11. LED does not light or only light does not put out:
Check the LED tube itself is good; and then check U14, U16 (8910 is normal, U14 control the lower right two groups, U16 control left upper two groups of LED).