| Electronics > Repair |
| 30v Power supply does not go over 7.9 volts |
| (1/2) > >> |
| jansjobe:
Hi all! I have a chinese power supply that chokes over 7.9 volts. As i turn the voltage adjust pot further, it shorts and no voltage output. I have removed the diode on the output, but it makes no difference. I have attached the schematic. Can somebody help? |
| FIXITNOW2003:
if you search "power supply K305D" you will find loads off post on these units, lots off Chinese makers but all the same unit lots off faults mostly poor soldering and duff diodes |
| jansjobe:
Well, thanks, but I would like to know how it works and what I should look for. Search for K305 gives only this thread as a hit... |
| xavier60:
It's a complicated design. The wiper pin on the VR pot should adjust smoothly over a range of 0 to 5 volts. Check the voltage on pin 2 of U4. Check the supply pin voltages on U1. |
| ArdWar:
The abrupt nature looks like U4 pin 9 is crowbar-ed by one of, uhh, things that also connected to pin 8. Fuck you whoever drew schematics like that... |
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