Re: Hanns-G HG281D, LCD Monitor no power
Hi Steven_C,
how did you determine the main transformer is bad? Transformers usually have a low-failure rate (LCD backlight inverter transformers aside).
If you know and can provide all of the outputs, then it should be possible. Don't hook up the external PSU to the transformer pin locations though - not unless the transformer is removed. Otherwise, you'll be connecting your external PSU across a short circuit (well, pretty much, since the secondaries of these transformers are only a few turns - which is also why they read low resistance on multimeters).
However, you said the middle pin is connected to a diode which you are not sure what voltage it is - in this case I wouldn't recommend hooking up an external PSU without first knowing what voltage should be present there. To me, it looks like some sort of feedback or power supply for U801. Not exactly sure though - the pics in this thread are pretty good, but just don't have the details I need. Feel free to post your own pictures.
Going by the pics posted in this thread, the 5v rail does seem to be derived from the 12v output (via Q501 and Q502). But again, this is based on someone else's pictures. It's usually a good idea to post your own pictures, just in case there is a difference in the PSU board somewhere.
Originally posted by Steven_C
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how did you determine the main transformer is bad? Transformers usually have a low-failure rate (LCD backlight inverter transformers aside).
Originally posted by Steven_C
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However, you said the middle pin is connected to a diode which you are not sure what voltage it is - in this case I wouldn't recommend hooking up an external PSU without first knowing what voltage should be present there. To me, it looks like some sort of feedback or power supply for U801. Not exactly sure though - the pics in this thread are pretty good, but just don't have the details I need. Feel free to post your own pictures.
Originally posted by Steven_C
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