Funai (Emerson) LF501EM4F not turning on

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Out of curiosity when everything is connected what DC voltage do you have at pin 7 & pin 14 of IC1101, IC1201 and IC1301. Trying to figure out which IC is going into protection mode.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

i got bored and opened it up all leds came on when forced on

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Does it have more than one issue. since it the main cap reads 217 all hooked up normal no jumping pins once plugged into the wall 217 unless its only power board and leds

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

What do you have on PROTECT3 when you force on the backlights/power supply?
When the cable from the power supply to the main board is disconnected and then you force on the power supply/backlights circuit, if that PRTOECT 3 ERROR SIGNAL is low due to error it WILL NOT SHUTDONW that backlights circuit because that signal is sent to the main board and then the main board manages the shutdown function.

1.73v... on protect 3 while PS-ON+ BackLights SW+ADJ jumped on only poweboard+led lights

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

What do you have on PROTECT3 when you force on the backlights/power supply?
When the cable from the power supply to the main board is disconnected and then you force on the power supply/backlights circuit, if that PRTOECT 3 ERROR SIGNAL is low due to error it WILL NOT SHUTDONW that backlights circuit because that signal is sent to the main board and then the main board manages the shutdown function.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Have you carried out the test as given in post #10 by CapLeaker.
With the mainboard disconnected and using the jumper resistors as directed can you check your backlights are on and also what the DC voltage is across the main capacitor.

Yes i have black lights will turn on and stay on fine voltage all rails. 217 while on with back lights on , suspected a led issue but why would it have voltage if main board is connected to power board all rails are live once plugged in and 217 at main cap no back lights or effect hitting power button still 217

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Have you carried out the test as given in post #10 by CapLeaker.
With the mainboard disconnected and using the jumper resistors as directed can you check your backlights are on and also what the DC voltage is across the main capacitor.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Can you attach your pictures to this thread for other to see at a later time should they too have this problem.

The mosfets pass the test.
What was the picture shown in post#25 about?

Wrong test i did it on Q601 the diodes just tested 0.455 on diode test function . anything else to remove..? person i got tv from before the steady power light flash every 10 seconds was able to unplug , plug in and hrs or days it came on or was able to turn on

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Can you attach your pictures to this thread for other to see at a later time should they too have this problem.

The mosfets pass the test.
What was the picture shown in post#25 about?

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

okay took them off http://imgur.com/a/BHjkt Q1601 C=1.28nf Vt=3.2v Q1602 C=1.29nf Vt=3.3

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Is that picture of testing Q1601 / Q1602?

Q601 was no Q1601 just a Q1602 sorry i misread there is showed same on board removing leg now for Q1602

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Is that picture of testing Q1601 / Q1602?

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

With the power off check diodes D1603 & D1605 and mosfets Q1601 & Q1602 using you meter in diode mode.

If you are uncertain how to test them then there are plenty of Youtube videos to guide you.

Maybe we getting somewhere now D1603 & D1605 diodes tested good if okay to test on board Mosfets however Quick and Dirty test first with dvm did no match anything from video(even after i got out the iron and lifted gate leg) I then tried quick and dirty again then mega tester from ebay.
http://imgur.com/a/VgblK

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

With the power off check diodes D1603 & D1605 and mosfets Q1601 & Q1602 using you meter in diode mode.

If you are uncertain how to test them then there are plenty of Youtube videos to guide you.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Not sure if this points in one direction but it seems the Power is on from the moment it is plugged in if main board is connected.(tried with/without lvcd+ribbon to ir sensor board no speakers all same) Pfc_out is always 217... But if it is just power board alone or with led plug it is 160-170v and only 217v once i jump ps_on i read 6pin conntor to lcd/led they read same 3 around 76v also not sure if that'd make the drivers okay

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

You have three LED driver ICs with fault output (FAILB) OR together so if one of the LED driver circuit detect fault it will take PROTECT3 line low, see schematic on how PROTECT3 signal is generated and the spec sheet of the IC BD9488F.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

ill be back in a few hours but can i bypass protect 3 with grounding out the the timer? I dont wanna fry anything tho more

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

I would say 217.5V is low, the PROTECT3 should be 3V when TV is turn on, look at the schematic.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Is my pfc okay being 217.5v? Should PROTECT 3 have voltage with PS off? When i jumped PS_ON and BL-sw and Bl-adj PROTECT 3 shows around 2.6

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

The PFC Voltage will not be 380~400 VDC on this power supply board, more likely 250~280 VDC range, that is why the cap is only rated at 400VDC.
BTW, normal condition the PROTECT 3 should around 3 VDC, <1V indicate error in the backlights circuit.