I'm a beginner in electronics repairing and I need help troubleshooting a tv which doesn't turt on, neither the power LED lights up.

The board is a cheap chinese (check the attached image). When I opened it and started troubleshooting I found out that the H. O. T was shorted, and the fuse was blown. I made some checking on a few other components and I couldn't find any other fault. So I replaced the defective components (fuse and h.o.t).

Then I powered it up through a 60W series bulb but it didn't turn on, so I measured some voltages, the readings are as follows: Mains Filter - 315V, H.O.T Vce - 315V, R531 was open, I replaced it. I traced the voltage from R520 and it's dead (0) after R522 (check the attached image). And THERE'S NO VOLTAGE ON THE SECONDARY SIDE. Can someone help me by explaining what's going on AND/OR what to do? Power supply schematics

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    \$\begingroup\$ Some people have voted to close this as a bad repair question. The reasons states "must involve specific troubleshooting steps and demonstrate a good understanding of the underlying design". OP has supplied a schematic, traced the necessary voltages, identified where the problem happens, and obviously knows enough to measure more. What else do people need here? \$\endgroup\$ – pipe Oct 9 '18 at 11:58
  • \$\begingroup\$ If V512 is permanently switched on, there will be current flowing through R520, R521, R522 and R524. With 315v across those resistors, from my calculations, I would expect approximately 15v across R522, \$\endgroup\$ – HandyHowie Oct 9 '18 at 12:40
  • \$\begingroup\$ You should check/replace also V512, V511, VD514, R517, R524 R526 and the optocoupler N501. All were exposed to high voltage. I might have missed some parts. Also check for shorted diodes on the secondary side that might be the original source of the fault. \$\endgroup\$ – Dorian Oct 11 '18 at 13:01
  • \$\begingroup\$ Thanks a lot for all the replies, I had already replaced V512 and the set started, but now there's a new symptom: IT ONLY DISPLAYS A VERTICAL LINE IN THE MIDDLE OF THE SCREEN. I "googled" for it and the common phrase I got is "THE PROBLEM IS ON THE HORIZONTAL OUTPUT CIRCUIT". So I scanned that "area", retouched some dry joints, replaced Snubber cap with another from a junk board, same thing for the s-correction cap, but still the problem remains (I wish I had an esr meter) ...any advice? \$\endgroup\$ – Manhuque Afonso J. Saire Oct 13 '18 at 0:02
  • \$\begingroup\$ You could ask another question giving as much detail as possible including a scematic. \$\endgroup\$ – HandyHowie Oct 13 '18 at 8:40