I know the dot mean the start of the winding, but on this schematic the same winding have two dots, i can't find info regard this on internet so i come ask what that means. I meassure the 7 and 5 and give infinite resistance. That's from a TV PSU, not outputing any DC safe voltage, secondary coils are all 0V.

enter image description here

Schemantic PDF download

enter image description here enter image description here enter image description here

  • \$\begingroup\$ Mighty strange indeed! \$\endgroup\$
    – winny
    Commented Jul 6, 2018 at 21:38
  • \$\begingroup\$ Hey, did you figured out what was wrong with the schematics/ or the transformer? \$\endgroup\$
    – daniels_pa
    Commented Dec 10, 2018 at 9:26
  • \$\begingroup\$ Just looking at the schematics I have no idea what that coil 5-7 is used for, and on my PSU (also vestel garbage 17IPS10-3) it also seems open. Also i get the connection between 1 and 4. For which im starting to think the transformer is bad since 1 goes dirrectly to RECT AC \$\endgroup\$
    – daniels_pa
    Commented Dec 10, 2018 at 9:44
  • \$\begingroup\$ No, i end to order another PSU, but the problem was not with transformer \$\endgroup\$ Commented Dec 11, 2018 at 15:57

1 Answer 1


That means you're out of luck with that diagram, they really screwed up. The direction of the first coil will not be able to be determined from the schematic. You could pull it out and run a waveform from a signal generator to determine the directions.

If the coil from 7 to 5 really is open (and you believe the schematic) the transformer is probably bad (or the schematic is wrong).

  • 1
    \$\begingroup\$ looks like the diode/capacitor network is across pins 5 and 7 (DIODE_OUT) ..... maybe the transformer is available with the 5-7 winding in either direction, and the two dots mean that it does not matter which version is used .... only guessing at it though \$\endgroup\$
    – jsotola
    Commented Jul 6, 2018 at 16:31
  • \$\begingroup\$ I have added the schemantic link on post. All parts and labels are correct with the board and schmenatic, only this seen incorrect or maybe have a hidden meaning for the manufacture? Well i can try probe C919 to PIN 7 and check if theres a connection, if so the schemantic is ok and the transformer can be damaged? All other pins are OK and have the correct voltage, like RECT_AC, 6,3 NC, so i belive schemantic is correct \$\endgroup\$ Commented Jul 6, 2018 at 16:44
  • \$\begingroup\$ Added board picture \$\endgroup\$ Commented Jul 6, 2018 at 17:04

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.