| Electronics > Repair |
| Help Please, Switching Power supply shutting stright off. |
| << < (3/8) > >> |
| Harry_22:
Try starting the PSU and then connecting the yellow wire. Also measure the voltage on C8 when the unit is working and not working. |
| JFerris321:
C8 is 11.4 volts when the supply is working, as soon as i connect the yellow wire the supply shuts off and the voltage drops to 6.4 volt and remains there even when the yellow wire is disconnected again. infact with the yellow wire disconected the device will not work until the main hv cap has discharged completely. |
| tooki:
--- Quote from: JFerris321 on June 07, 2024, 11:33:51 pm ---The capacitors at c2,c3 and c4 are all CS472M. Datasheet says they have a capacitance of 472, how ever i believe that it is 0.472uf. Unfortunatly it is not possable to get pictures that show much details of values as most components have there values faceing other components. --- End quote --- That is not how ceramic cap values work. The last digit is the multiplier, and the final value is in pF. So 472 = 47 followed by 2 zeroes: 4700pF, or 4.7nF. |
| Harry_22:
--- Quote from: JFerris321 on June 08, 2024, 03:33:51 pm ---C8 is 11.4 volts when the supply is working, as soon as i connect the yellow wire the supply shuts off and the voltage drops to 6.4 volt and remains there even when the yellow wire is disconnected again. infact with the yellow wire disconected the device will not work until the main hv cap has discharged completely. --- End quote --- Very interesting case. i like it! Your controller supply voltage is underestimated even when it is working. At 11.5 it can already turn off. Also the voltage doesn't return to normal during restart. This indicates the increased consumption. Unsolder R12, connect external power supply to C8. Gradually increase the supply voltage and measure the starting and operating current. You can control the status via 5 volts on pin 8. It is there when the controller is running and disappears when it stops. Please also measure the reverse process of reducing current consumption when reducing the controller supply voltage. |
| asis:
Hi, @JFerris321 Important point. Do you carry out all your manipulations with a connected load? At least some. Especially at the voltage output of the channel to which the optocoupler with the REF circuit is connected. |
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