Emerson LF501EM6F has 21v and 13v but no vled+27v

[triplefour]

Re: Emerson LF501EM6F has 21v and 13v but no vled+27v

D656 charges C656 and before D657 starts to conduct, there is 0 volts on Q654 base, so the collector is being pulled high by R653 which is connected to AL3.3v so Q650 will be turned ON, and the reset pin will be LOW, as soon as D657 conducts and supplies voltage to Q654 base, Q654 conducts turning Q650 OFF and the reset pin is then HIGH.
The RESET is used to RESET the microprocessor

So is the tv working now?

thank you for that explanation. i will read and re-read, and look at the circuit until i understand it.

yes the TV is working. i have it running playing a DVD for maybe half hour now.
maybe the gekko damage had nothing to do with anything. maybe it was always just a loose connection that plugging and unplugging the boards and connectors has resolved. who knows? but at least i know how to trick these power supplies on, so if the TV goes down again it will be easy to tell which part it is.

and i can be fairly confident in testing these PSU's all by themselves because i can at least see the VLED+27 line come up for some time before fading away

[nomoresonys]

Re: Emerson LF501EM6F has 21v and 13v but no vled+27v

those backs cover pretty well, hellofa mystery how a gecko could get in there.

[triplefour]

Re: Emerson LF501EM6F has 21v and 13v but no vled+27v

those backs cover pretty well, hellofa mystery how a gecko could get in there.

yes the back does cover up well enough to stop such a big gecko from getting in there. but when you take the stand off to wall mount the tv, it leaves a hole where the stand went that is quite big! i have something new to warn people about!

[nomoresonys]

Re: Emerson LF501EM6F has 21v and 13v but no vled+27v

ah, ok, I should have been able to figure that out,