Funai (Emerson) LF501EM4F not turning on

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Something around IC1101 is pulling the Protect3 low.
With the power supply off, and I assume the resistors R1108, R1208 and R1308 are still out of circuit, can you do a diode test on D1107 and compare your results to D1207 & D1307

[dick_barton]

Re: Funai (Emerson) LF501EM4F not turning on

Reading through the posts again, you said in post #54 - 56 that Q1102 tested bad but did not give a reason as to how it was bad.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Can who ever knows he protect 3 circuit explain it a bit more simply? 3.2 vdc needs to be powered to PROTECT3 1341 IC3001(2/5)MSD8200DS-S1 but instead to R3193 because Q3103 is either messed up or whats left of protect 3 circuit is grounded ? that 3.2vdc is being bought to main board at P-ON+3.3V from power board? Thats what i got so far am i correct?

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

OK, I just study type 'B' main board dagram, you need to see if you do have LCD+12V at the LVDS connector CN3013 pin 1~4 or not, leave the meter on one of those pins so you can catch the Voltage when you first turn on the TV so you can see what happen before the TV goes into shutdown mode.
BTW, we know that you have problem in the LED driver circuit for the LED 1 because you not getting the booted Voltage, you are getting that 40 something Volt input Voltage right now, that to be solve later, right now need to be able to turn on TV and all the power supplies should come up and stay up first with using the force on.
If the LCD+12V is missing, that will also trip the protection circuit.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

OK, I just study type 'B' main board dagram, you need to see if you do have LCD+12V at the LVDS connector CN3013 pin 1~4 or not, leave the meter on one of those pins so you can catch the Voltage when you first turn on the TV so you can see what happen before the TV goes into shutdown mode.
BTW, we know that you have problem in the LED driver circuit for the LED 1 because you not getting the booted Voltage, you are getting that 40 something Volt input Voltage right now, that to be solve later, right now need to be able to turn on TV and all the power supplies should come up and stay up first with using the force on.
If the LCD+12V is missing, that will also trip the protection circuit.

It reads .0065vdc and stays at that from the moment it is plugged in i checked as top right was pin 1. checked left side had 0.00vdc

tv hooked up normally ,

checked +21v and had 21vdc also 3.3vdc at ps-on and 12vdc at amp-13v+

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

OK, we are getting some where, so it never goes up to +12V to feed the T-CON.
I found many sensing circuits that many Voltages on the main board that will trip the PROTECT 1 and PROTECT 3. At first I thought PROTECT3 is just for monitoring the Backlights circuit, but it turns out to be that it also monitoring the LCD +12V.
If you look at Digital main 1 TYPE b, you will see that IC3201(MP1472GJC4527) is the down converter that converts the PON+21V down to 12V for running the T-CON, IC3201 is turned on by the CELL-PWR-CTAL signal generated by IC3001 (Micro Controller) pin 76.
So you need to check IC3201 Pin 7 (+21V input), and EN pin2 for >2V or more for ON signal.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

OK, we are getting some where, so it never goes up to +12V to feed the T-CON.
I found many sensing circuits that many Voltages on the main board that will trip the PROTECT 1 and PROTECT 3. At first I thought PROTECT3 is just for monitoring the Backlights circuit, but it turns out to be that it also monitoring the LCD +12V.
If you look at Digital main 1 TYPE b, you will see that IC3201(MP1472GJC4527) is the down converter that converts the PON+21V down to 12V for running the T-CON, IC3201 is turned on by the CELL-PWR-CTAL signal generated by IC3001 (Micro Controller) pin 76.
So you need to check IC3201 Pin 7 (+21V input), and EN pin2 for >2V or more for ON signal.

0.28vdc for pin 2 and pin 7 21.17vdc no change both start and stay at voltage

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Heres how i labled

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

0.28vdc for pin 2 and pin 7 21.17vdc no change both start and stay at voltage

OK, so the Controller is not sending the signal to turn on that Buck converter.
So at this point you do have problem with the main board + LED1 drive circuit.
i am not sure how much you will want to pursue these two problems and hoping there is no other problem too.
You can force on this IC by removing R3213 first and then use 100K resistor between EN pin and the IN pin to see if it will put out the 12V or not.
MP1472 spec attached.
Right now to me it is about the learning how the circuits operate.

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

OK, so the Controller is not sending the signal to turn on that Buck converter.
So at this point you do have problem with the main board + LED1 drive circuit.
i am not sure how much you will want to pursue these two problems and hoping there is no other problem too.
You can force on this IC by removing R3213 first and then use 100K resistor between EN pin and the IN pin to see if it will put out the 12V or not.
MP1472 spec attached.
Right now to me it is about the learning how the circuits operate.

Awesome i'll remove R3213 once i find a 100k ohm resister to use from parts electronic boards, DO i solder that between EN AND IN? and if no other issues it should start up normal? if not check +12 at lvcs again?

[jayjoesph]

Re: Funai (Emerson) LF501EM4F not turning on

Awesome i'll remove R3213 once i find a 100k ohm resister to use from parts electronic boards, DO i solder that between EN AND IN? and if no other issues it should start up normal? if not check +12 at lvcs again?

No luck there ill triple check the resistor is on fine i removed r3213 no +12 at lvcs 103 Ohms 10% should be okay ?

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

If the EN pin is high when using the PULL-UP resistor 100K (I would say 47K~100K should be fine. and you do have 21V going into it then you should have LCD+12V.
If not, then tell use what you have:
1) on EN pin when you use the resistor between EN and Vin pin.
2) What is the resistance reading between the LCD+12V and GND? We want to know if it show low resistance reading or not.
You can possibly have bad IC too.

[trend@wp.pl]

Re: Funai (Emerson) LF501EM4F not turning on

I'm calling here because it's probably a similar tv.
I am trying to fix Tv LF501EM5 (funai / emerson).
The TV does not turn on. The power supply looks functional.
It seems to me that I have a low resistance in branch 21v (22ohm) on the signal board Ba4gu5g0201-3. Can anyone somewhere have a schematic for this version.
I would be grateful.

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

Check the resistance of the C3214 10uF MLC CAP on the main board.

[trend@wp.pl]

Check the resistance of the C3214 10uF MLC CAP on the main board.

Perfect shot it was c3214 . TV is working like new . Thanks a million. If you will be visiting Tampa let me know. Big thank .

[budm]

Re: Funai (Emerson) LF501EM4F not turning on

Thanks for the follow-up.