LG 32LN578V PS b/d issue

[notallbad]

PS b/d: 3PCR00274A, EAX64905001 (2.7)
Panel: LC320DUE
Main b/d: NC4-M-TU24

P801 - stby 0v, when On spurious reading of only 1 or 2v (dmm across P801 neg and pos legs). However, get 46v across P801 pos leg and P201 Gnd pin in stby and fluctuating around 118-125v when on, with P801 backlight plug connected and disconnected.

C109 & C110 both read 319v in stby and drops to 316v when on.

Is this a sign of a short cct somewhere pulling down the voltage?

P201 voltages:
Gnd - -
12v - 11.45v
12v - 11.45v
Gnd - -
24v - 22.6v
Gnd - -
3.5v 3.24v 3.3v
3.5v 3.24v 3.3v
PWR-On - 3.19v

Gnd - -
N.C - -
12v - 11.45v
Gnd - -
24v - 22.6v
Gnd - -
N.C - -
PDIM - 3v but drops to 2.36v then again to 1.04V
DRV_On - 2.83v

Also, when the power source is removed, i.e turn off at the wall socket, the red led stby light stays lit for a whole minute before distinguishing. Def not normal behaviour! Would this suggest a cap issue?

[budm]

Re: LG 32LN578V PS b/d issue

We need pictures of the boards and how they are all connected together first so we can see what we are dealing with.

[dick_barton]

Re: LG 32LN578V PS b/d issue

Sounds like led(s) problem.

[vinceroger69]

Re: LG 32LN578V PS b/d issue

This thread maybe worth a read and also has the schematic of the psu

https://www.badcaps.net/forum/showth...ht=LG+32LN578V

[notallbad]

Re: LG 32LN578V PS b/d issue

Photos of PS b/d

[notallbad]

Re: LG 32LN578V PS b/d issue

Map3202 readings

[dick_barton]

Re: LG 32LN578V PS b/d issue

The MAP3202 voltages look fine.
VCC is within the operating specifications and the REF output may not be quite 5V, but close enough.
The OVP looks as though it may be kicking in which would indicate the led voltage is too high which happens when there is no load due to open circuit led(s)

I still suspect you have led faults.

[notallbad]

Re: LG 32LN578V PS b/d issue

Thanks Dick
appreciate it! I just didnt want to be stripping the lcd before being more certain it is in fact the leds, well hoping it wasnt I suppose.
thanks again, shall strip down and investigate leds and report back.

[dick_barton]

Re: LG 32LN578V PS b/d issue

Where in the UK are you located?

[notallbad]

Re: LG 32LN578V PS b/d issue

Swindon Wiltshire

[notallbad]

Re: LG 32LN578V PS b/d issue

Stripped down the panel to find 1 led not working on the 1st strip I tested, so what leds are needed to replace them? SMD 3528 1W 100lm cool white any good?
Not sure my soldering skills are up to these delicate leds but worth a try for a few quid.

[vinceroger69]

Re: LG 32LN578V PS b/d issue

i have used this seller before he sells various leds

http://www.ebay.co.uk/itm/LG-47LN540...IAAOSwBLdZp~ON

[notallbad]

Re: LG 32LN578V PS b/d issue

Photo of B1 & B2 Type led array strips

32" V13 Rev 0.0 1 B2-Type 6916L-1437A
32" V13 Rev 0.0 1 B1-Type 6916L-1438A

[Davyn]

Re: LG 32LN578V PS b/d issue

Hi, I have an issue with my LG television.
Standby light blinks 2 times and dies, but nothing happens.
I have checked the PSU board, but caps are good.

Anything else I should consider looking at here?

[notallbad]

Re: LG 32LN578V PS b/d issue

yes same as me, LED's!

[notallbad]

Re: LG 32LN578V PS b/d issue

Tried 3528's but they just give out as soon as its powered up so must need 6v.

[vinceroger69]

Re: LG 32LN578V PS b/d issue

this is the specs of the lcd im sure theres a way too work out the led voltage but i cant remember how im sure budm will advise
http://www.panelook.com/LC320DUE-FGA...ter_23221.html

im sure you divide the max led voltage by the amount of leds so 127.8 divided by 21 leds 6.08571429 volts so yes 6v leds in my opinion

have you got a proper led tester as it will tell you the led voltage across one led

maybe these but you will need to confirm the mah hours etc this is where i usually ask budm for help before ordering
https://www.aliexpress.com/item/50pc...StoreLevelAB=3

[notallbad]

Re: LG 32LN578V PS b/d issue

shall try 6v 3535's.

it takes soooo long for delivery from china etc but refuse to pay the extortionate cost from uk sellers but if these dont work I may end up doing just that! bummer

[vinceroger69]

Re: LG 32LN578V PS b/d issue

yes ordering from china is taking roughly 6 weeks i notice lately not sure if rs etc sells leds? as you know the colour size voltage and amps needed so maybe worth a look

[notallbad]

Re: LG 32LN578V PS b/d issue

Hi, I have an issue with my LG television.
Standby light blinks 2 times and dies, but nothing happens.
I have checked the PSU board, but caps are good.

Anything else I should consider looking at here?

yes front LED flashes twice