Re: 55EC930V Help please
I have some programmers. Depends on what processor....
jram
Member
Last Activity: 12-05-2020, 09:44 AM
Joined: 08-27-2019
Location: Colchester
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Re: 55EC930V Help please
I'm back!
I started again. Doing test 1, P2300 voltages are good apart from Pin 4 which is zero volts. I see no mention of the significance of pin 4 in the SMPS PDF so I thought I'd ask for guidance please
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Re: 55EC930V Help please
Sorry for my absence guys - Had to go away for 2 weeks last night. Will hopefully conclude this epic after the 26th! Thanks for all your help - P.S. I'll get a bulb by then
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Re: 55EC930V Help please
OK - With T-Con and main board connected, it clicks on and then off after 3 seconds. Switching on at the power button has the same result. The voltages, however stabilise at 12 and 24V and P201 and P202 while its on.Leave a comment:
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Re: 55EC930V Help please
Good job guys. Now we are getting closer to the original problem.
I can't check the 24V power delivery since I don't have a bulb!
So I have connected the T-CON and also the main board and applied power. The relay clicks on and after 10 seconds or so, clicks off.
If I disconnect the main board and replace the jumpers and apply power, the relay clicks on and stays on. The screen is mostly black with broken white horizontal lines the full width of the screen in a band that is about 1/4 up from the bottom and 1/4 screen height...Leave a comment:
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Re: 55EC930V Help please
C509 replaced - CLICK!
Now to start checking voltages...
With only Pins 1 and 3 jumpered, 12V and 24 V present on correct pins of P102 - working through the rest of the troubleshooting guide - will updateLast edited by jram; 09-10-2019, 01:14 PM.Leave a comment:
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Re: 55EC930V Help please
Thanks R_J - I see where we are going with this.
OK - ZD502 is not shorted.
Coil resistance 49.7 ohms - neither the diode or cap shorted (i.e. resistance across each consistent at 49.7).
I checked the Q501 voltages with the jumper in and out - 17V collector and Zero B/E - no Jumper. With Jumper 2V Collector and 500mV B/E so its turning on a little but not enough.
I checked further down the chain C509 has a resistance of only 5 Ohms. I'm going to replace it and see what happens...Leave a comment:
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Re: 55EC930V Help please
Ok, Firstly, thank you both for your help
@R_J
My initial voltages were erroneous vs chassis - the correct voltages are 331 vs C621 (-ve)
I measured the following voltages vs J50 with no jumper then with jumper P1 (verified by coloured wire and triangle on the board) to P3 the next pin up.
C507 17.0 0-2V
C503 16.5 6.6-6.7
C504 15.3 13.6-14
I don't have the experience to tell which cap is bad (no schematic) but I'm guessing its C507?Leave a comment:
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Re: 55EC930V Help please
With pin 3 connected to to pin 1, the pin 3 voltage oscillates at about 1-2Hz between 1-2.6 V. There is no click, there is no 12V or 24V measurable. Pretty much the same results as my 1st post.
Anyone got a circuit diagram?
ThanksLeave a comment:
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Re: 55EC930V Help please
Thank you - I'll get to it
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Re: 55EC930V Help please
@nomoresonys, my results at #10. Had to flip the board over but can't see it would make much difference since it was still connected to the other boards per the instructions.
Seems there is a problem getting the 12 and 24V to start/hold onLeave a comment:
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Re: 55EC930V Help please
This is the recommended technique from @nomoresonys.
For your technique, please may I ask you to answer with details of your technique, test points used and any other information available?
Many thanks...Leave a comment:
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Re: 55EC930V Help please
Thanks for your patience - sorry
OK with the PWR button held ON
0 0
0-5mV 2-40mV*
0-35mV* 2-40mV*
0 0
0-5mV* 1-5mV*
0 0
3.55V 3.55V
0 3.55V
1.9 - 50mV 0-?? Volts - oscillates high enough to get the meter to switch scales and then cuts off to zero and restarts - period about 2 seconds
*These values oscillate up and down with a period of about 2-3 seconds
Thank...Leave a comment:
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Re: 55EC930V Help please
OK - I'm back! Many thanks for your good wishes
I made sure everything was plugged in but inverted the power board to gain access to P201 pins from the rear. I attach a picture of the pins and the legend above
The voltages are as follows:
System power on but in standby
0 0
0 0
0 0
0 0
0 0
0 0
3.55 3.55
0 3.55
1.9mV 0
I then pressed the remote power button once. The LG led dimmed and recovered.
...Leave a comment:
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Re: 55EC930V Help please
@nomoresonys Thank you, I will. Unfortunately have to go away for some days due to family illness - will catch up next week. Thanks for your help
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Re: 55EC930V Help please
Ok, Thanks for the feedback guys,
@nomoresonys - I'll attach the photos below.
@R_J - The fuses are all good. On checking the voltage to the Opto with the link across pins 1&3, I see a fluctuating voltage of 1V +- 0.1v which is not good (I expected 3.55V - correct?).
With the link removed, I see a steady 3.55V at the terminals on IC503 (on the low side)...Leave a comment:
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55EC930V Help please
Ok, I have downloaded the SMPS guide.
The symptoms are that the LG symbol lights and flickers when the black power button on the back of the unit is pressed and also when the remote power button is pressed. The TV does not power on.
AC (240V) is present ath the sck100? where the power arrives on the main board. All fuses are intact and all apart from the one by the main socket have 120V.
Power Supply Board Low Voltage Test 1 yields the following:
3.5V at pins 3 and 5 of P201.
I disconnected P2300 ribbon cable and added R110 across...Last edited by jram; 08-27-2019, 03:48 PM. -
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Thanks for having me here! Very glad I found this forum!Leave a comment:
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