thankyou, just as suspected but great to have it confirmed.
Regards
Rob
notallbad
Badcaps Legend
Last Activity: Yesterday, 06:38 PM
Joined: 10-12-2012
Location: UK
-
Photo for clarification...
Leave a comment:
-
2U2M63 Cap polarised or not?
Just wondered if anyone knows if this cap is polarised or not, its a small blue rectangular through hole style.
Shall add a photo shortly, came off a board and not sure which way it goes back on, if its not polarised it wont be an issue but just need to be sure before remounting.
thankyou -
just curious but would a power board from a 43" or 50" of the same tv range work i.e 43rp620k, 50rp620k?
I did buy one in the hope it would but backlights just flash on and off as soon as power is applied. I guessed it only for 43 or 50" with fewer leds to run i.e 40" 21 leds, 50" 26 leds rather than 55" with 30 leds.
With the leds disconnected the tv turns on and operates fine.
Though it was sold and advertised for 43, 50 or 55".
Perhaps just needs repairing properly as the only replacement on the board is the led...Last edited by notallbad; 07-13-2025, 10:15 AM.Leave a comment:
-
Been running the tv with backlight at 45% for a good few minutes more than it lasted before so fingers crossed. Shall increase the backlight once happy its ok at 45%.
I did also check the blue ceramic caps beforehand and all seemed good.Last edited by notallbad; 07-13-2025, 06:02 AM.Leave a comment:
-
ok so have now changed all 3 - diode, mosfet and led driver i.c, the diode and led driver i.c seem to be ok comparing readings out of circuit to new components so just the mosfet blown this time.Leave a comment:
-
thanks, shall try replacing all 3 at once as I have more spares.
How do you test the blue ceramic caps?Leave a comment:
-
TCL 55RP620K power board issue
Originally the tv arrived with dimmed backlights (not failed leds) but everything else worked ok. Adjusting backlight in menu did nothing but voltage changed on dimming control pins,
0% p_dim at 1.65v and a_dim at 1v
50% p_dim at 3.3v and a_dim at 1.65v
100% p_dim at 3.3v and a_dim at 2.88v
Changed backlight leds anyway as always like to have complete peace of mind they wont fail shortly after selling the tv. No change as expected!
Leds are 2 rows of 15 6v leds.
On inspection of the power board found diode MBR3200 shorted so replaced with... -
DMM diode test showed as shorted both ways.Leave a comment:
-
So found the culprit, a failed diode D607 MUR460.
Replaced and now buzzing gone! Back down to a susceptible level.Leave a comment:
-
LG 55LM6200 buzzing / humming power board
Having replaced a brand new full led backlight set and fixing a mainboard fault (power-on transistor) theres now a louder than normal hum / buzz coming from the power board in the AC filter, namely in the LF101 / 2 area, or at least thats where the sound is more resonant whilst the backlight is set at 100%. Turn down the backlight to 50% its less noticeable and 0% its non-audible.
When the rear case is fitted back on its more audible and its certainly more than an acceptable level so would rather solve than leave like it.
Have powered on the tv with panel disconnected...Last edited by notallbad; 12-04-2024, 07:06 PM. -
So hopefully just to complete this repair,
continued to heat the transistor before every power on and start up and it worked every time so replaced the transistor and now getting 3.4v on power-on pin and tv turns on from cold start every time!Leave a comment:
-
yh, the reason why I was using heat. But curious that when directing heat at the bipolar transistor, though of course heat can quuckly transfer, the rv powers up from 'cold start'. Believe as its heated a greater current flows.
Might just buy one and swap it over and see! Shall heat before powering on a few more times from 'cold' just to confirm it gives consistent results.Last edited by notallbad; 11-26-2024, 03:06 PM.Leave a comment:
-
With everything connected as normal apply power and get 3.5v stby as expected. Power on and get power_on 0.6v but no 12v or 24v, apply heat to the main board in the area below the main-psu connector and 12v and 24v appear and 5 blinks on ps board. Press power button and wham, invertor_on, p_dim and pwm_dim appear - backlights on and tv working.
Not sure if this is just causing a fault condition and resetting the micom which brings the tv back to life or if its a faulty component/solder joint/pcb trace fracture.
But then attempt to reproduce these results but now the power_on...Last edited by notallbad; 11-26-2024, 11:48 AM.Leave a comment:
-
Main to PSU disconnected and using 2 1kohm resistors for power_on and invertor on/off from 3.5v stby get the backlights come on and 6 flashes from the ps board led.
With the led connectors removed the ps board flashes 5 times from power up then continually flashes 3 times.Last edited by notallbad; 11-26-2024, 07:39 AM.Leave a comment:
-
From a 'Cold' start (i.e not been powered up for a good few hours), Power up psu standalone with just leds connected and 1kohm resistor between 3m5v stby and power_on, get the following
1 power_on 1.6v
3 24v 24.9v
5 gnd 0v
7 gnd 0v
9 3.5v 3.5v
11 3.5v
13 gnd 0v
15 gnd 0v
17 12v 12.1v
19 12v 12.1v
21 12v 12.1v
23 gnd/P_Dim2 3.5v
2 24v 24.9v
4 24v 24.9v
6 gnd 0v
8 gnd 0v
10 3.5v 3.5v
12 3.5v 3.5v
14 gnd 0v
16 gnd 0v
18 invertor on/off 0v
20 led n.c 0v...Last edited by notallbad; 11-24-2024, 03:44 PM.Leave a comment:
-
LG 55LM6200-TA not powering up
The TV sometimes turns on fine, sometimes it doesnt.
Checked the PS voltages to find that PS_On sometimes reads 1.1v and drops off to around 0.9v which is enough for the tv to turn on, other times theres no voltage reading or around 0.7v which is not enough to switch on, would think this should be around 3.3v.
So disconnected the ps_on wire between main and psu and jumpered a 1k ohm resistor across the ps_on and one of the 3.5v stby pins - the ps board powers up fine and the tv turns on when power button pressed but of course its less than ideal leaving it like this as... -
Leave a comment:
-
how are you getting on with this tv?
what options are there in the user menu?
Service menu changes and fw flashing should be last resort!Leave a comment:
-
LG Service menu android app
I had been using wave audio files to play via the headphone jack to an ir led but had difficulty getting the InStop file to light the led, no sign of life when viewing the led through the camera app on my mobile phone.
Anyway, came across this free android app called IR Wave Plus that can utilise a homemade audio jack to ir led lead.
Not limited to just LG either!
A few settings require adjustment but the app itself is rather straightforward.
In settings ensure the slider bar is set to maximum and Force volume to 100% for audio ir blaster is ticked.
...
No activity results to display
Leave a comment: