Working of Regulator with 2 Photocoupler that is :
- Photocoupler N901 - used as a coupling-off control on the regulator by mikrokontrol. Which is set high and low voltage B + (st-by at the B + voltage is low). Control of the pin-37 POWER mikrokontrol → V610 → VD913 V908 → N901.
- Photocoupler N903 - used to control on-off the regulator of X-ray circuit protector. X-ray protector circuit of flyback → VD451 → VD452 → SCR VS472. If the flyback voltage regulator over the job will automatically be turned off by N903
- To disable the X-ray circuit protector, it can be temporarily removed photocoupler N903 first. In normal conditions the voltage at the transistor V474 should be zero.
- Disable by removing the first circuit protectors N903
- Check the voltage of 300V
- Check all transistors
- Check the start voltage of 300V by R909 >> R906 to the base of transistor power regulator
- Check the feedback C910 >> R904 (to oscillate)