Element elefc461 psu problem?

[triplefour]

on plugin get red sb light.
pwr btn no response
psu has 5vsb but doesnt respond to pwr on from mb
can be tricked only with mb not connected, and shows a fluctuating ~12v but i hear an infinite loop of "clicking"
but cant determine which component its coming from.
i noticed a diode D4 which appears cracked in half, yet still
reads some resistance (66.3 with meter set to 200k) one way and OL the other way (as a diode should?)
when i use diode check mode i get ol one way and 0.481 the other way.
12v output fluctuates between 11.6 and 11.9
voltage on one side of the diode goes OL even on 600v setting
endlessly fluctuating 19-31V on the other side (BANDED SIDE)
pretty clearly have a bad PSU
but could it be as simple as replacing that diode?

[R_J]

Re: Element elefc461 psu problem?

On this shopjimmy board d4 has a ferrite bead on its + lead, it is not split. post pictures of your board. 11.6 - 11.9 is close enough to 12 volts, D4 is on the HOT side, so you can not use chassis ground to measure the voltage, (must use hot ground)
What about the +24 volts, is it there when ps is forced on?
If stby +5 is ok, I suspect a fault with the main board

[triplefour]

Re: Element elefc461 psu problem?

finally got some time to look at this tv again...
and you ar right R_J i was on the hot side so should have used the negative leg of one of the filter caps instead of chassis ground. i dont know what was thinking
the diode is the same as in the picture on shopjimmy, ive just never seen a "beaded" diode before..whats that about?
the correct reading with correct ground reference is:
151VDC on the beaded side of D4
OL on the other side, even on 600v mode (still totally confused by this)
all four of the filter caps read 171v
this is in standby.
i checked the voltage at the button board connector and it is getting 3.5 which lowers depending on which button is pressed (so seems right?)
any chance theres an actual service manual on this tv, or is that pretty much a thing of the past now?
the fact that it clicks over and over again when "tricked" on without MB connected seems to suggest bad PSU, what makes you say MB suspect? can some PSU's not be tricked?

[triplefour]

Re: Element elefc461 psu problem?

by the way, this board is a pain in the ass to work on, since the labels for the output pins are on the underside of the board (thanks for that!) ... and also there doesnt appear to be any BL_ON (backlight on) pin to put 5v to force the Backlights on...
so when i said in my original post that i tricked the PSU on, i really should have mentioned that.
....
well great so after connecting pson to 5vsb, and i swear i didnt mess anything up or slip with a probe or anything, but now i am not getting 5vsb, and all my filter caps are reading 11v .... the fuse is still good...i didnt hear a pop or see anything smoke but my PSU is definitely buggered now, if it wasnt already was just trying to hear the "cycling click" as i had noticed in the first post....but never got there. psu is dead....and i have the creeping feeling again that for all my efforts, i still have no idea what im doing ((

ive watched all kinds of youtubes on switch mode power supplies but it always just gets super confusing and they never actually get to the part where they fix anything

[budm]

Re: Element elefc461 psu problem?

Can we see the pictures of the whole back side of the TV showing all the boards?

[R_J]

Re: Element elefc461 psu problem?

"all my filter caps are reading 11v "
If you only get 11 volts across ALL the caps, I guess you mean C1 or C2 or C3 or C53 your main fuse F1 is likely open