LG 27GL63T-B completely dead

[Joe Black]

Hello everyone!

Have this fine monitor, which doesn´t give any sign of life.
No LED diode, no reaction whatsoever.
PSU is OK, and there is 19V on both big caps and one pin of backlight connector,
for example.

Now, in these modern things there is only one board and no discreet components at all, so I really can´t start much with it.
Any help would be appriciated

Board no. is EAX68524502(1.1) and there are none selling in Europe

[unclejoe01]

I have the same monitor, have you had any luck repairing it?

[kylegp]

Same here. Seems to be a common fault for this monitor. I haven't worked out the cause.

[CapLeaker]

You got power going to the board, but nothing happens? Check the crystal. If the crystal isn’t working nothing else is either. Check the SPI flash and pull the data sheet. Check if you can update the firmware. Maybe this thing has a TTL port hook up to it and see what happens there. Look at the board and check the little buck converter(s) maybe one is shorted to GND.

These LGs are known for bad HDMI ports and playing dead with LED off. Maybe find a dump and flash it to the SPI. They look good, but that’s about it in my book.

[chronic519]

Same board, found a shorted cap beside the audio jack. Removed jack, short gone and 3.3 going to cap now. Found it to be the LED was shorted inside the jack. Still not getting LED light to power button. Going to continue search.

[jiroy]

Questions to be asked , did you follow CapLeaker instructions ?
Did you find a schematic ? ..
With no follow up , no high resolution image , no schematic , how can we be of any help ?
Anyway , the only help I can get is this service manual , as it's similar in identifying the culprit ..

[rodeo65]

Originally Posted by chronic519

Same board, found a shorted cap beside the audio jack. Removed jack, short gone and 3.3 going to cap now. Found it to be the LED was shorted inside the jack. Still not getting LED light to power button. Going to continue search.

My IC401 is shorted - heating like a hell, many people had same issue - 'MP9148GJ-Z MP9148GJ IAKX SOT23-8
In a series of monitors LG uk. ( sot23-8 IAKXJ,) it produces 1.2V (for cpu) / and 3.3V
- conversion to two x NCP1529-D
- e.g. cpu RTD2536R > chassis LM78A monitor LG 27MP59G-P (pcb: EAX67270701)
- LG 27GL63t > cpu MST9U35Q1 > chassis LM81A (EAX68524502 (1.1)) '

[rodeo65]

Hi I have here same screen with same issue - I hear buzzling noise close to jack. Will try to remove it and let you know more...

[johnny257]

i have the same board. mine was ic401(overheating 189C) and ic402(no v+ output). now all the coils have voltage. but still no power.. should i try to flash it?

i use this on both IC MP2122GJ-LF-Z

[doorzon]

Hi all,

have a LG 27GL63T as well with IC401 broken. There was no 1.2V and 1.8V, but the IC did not get hot.
Ordered some new MP9148GJ-Z MP9148GJ IAKX SOT23-8 from Aliexpress since local suppliers had no stock.

Data sheet:
https://www.monolithicpower.com/en/d...ument_id/1013/

With a bit of effort and lots of flux the chip was replaced. Monitor worked fine again straight after that. I did not verify the voltages afterwards to be honest.
Seems that this board design is quite bad looking at all the problems people have with it.

On some repair websites there was also a reference to replacing the 12MHz xtal should it still fail when 1.2V and 1.8V are back after IC401 replacement.
I think next time should this IC401 fail, I'll replace the chip with two separate buck converters of 1.2V and 1.8V that can better cope with the currents needed.

hope this helps anyone.

[rodeo65]

Originally Posted by doorzon

Hi all,

have a LG 27GL63T as well with IC401 broken. There was no 1.2V and 1.8V, but the IC did not get hot.
Ordered some new MP9148GJ-Z MP9148GJ IAKX SOT23-8 from Aliexpress since local suppliers had no stock.

Data sheet:
https://www.monolithicpower.com/en/d...ument_id/1013/

With a bit of effort and lots of flux the chip was replaced. Monitor worked fine again straight after that. I did not verify the voltages afterwards to be honest.
Seems that this board design is quite bad looking at all the problems people have with it.

On some repair websites there was also a reference to replacing the 12MHz xtal should it still fail when 1.2V and 1.8V are back after IC401 replacement.
I think next time should this IC401 fail, I'll replace the chip with two separate buck converters of 1.2V and 1.8V that can better cope with the currents needed.

hope this helps anyone.

12Mhz xtal is what please? Do you have link to aliexpress for example?

Thanks

Edit: no need to send link - my stupidity

[rodeo65]

I just replaced IC401 and no progress, found out IC402 has no output on pin 3. Coil is without Voltage. But Input is 19VOLTs thus have to order new IAGCK IC.

Maybe HDMI is issue, but how can I figure this out?

[vanarebane]

Another success story:

So similar symptoms, IC401 did not get hot, but little warm, so it stuck out on thermal camera. The short near audio jack turned out to be pull-down capacitor. Probably it's shorted when there is no audio jack inserted in the port. But also IC401 had no output voltages, so the device acted dead.

I replaced my IC401 with part named MP2149GJ-P (the original part has been retired) and the monitor started working. YAY!

The MP2149GJ-P is also rated 2A (original part was rated 1A). Not sure if this is total amperage or per channel. But if someone still has burned IC401, I suggest giving the MP2149GJ-P a try, it might be better version with more overhead.

Thanks also to everyone who contributed.

[odi]

Also troubleshooting a board with little signs of life. Similarly to rodeo65 ic402 no output on pin 3. Are we sure that this should have output? Is it possible this is the intended state while the board is off, and once powered on, this ic may be switched on?

[inv4der]

Hello, what should be the voltage on the coils L407, L408 and L410 ??

[rodeo65]

Guys who replaced ic401 and succeeded had you remove audio jack too? I removed it before but cannot find replacement on market. May it be cause why it is still dead?

Btw still waiting for new ic402 being shipped.

[Dannyx]

Hi guys. Having the exact same issue: IC401 felt slightly hot, so I removed it and indeed its ground pins were BOTH shorted to the 2 outputs. Trouble is, at some point, as I was messing with the board, trying to figure out what's shorted, I measured 5v on one of the outputs of IC401 (that's normally supposed to be 1.2/1.8v), so I'm afraid it may have took out the main IC too, although the resistances on both coils of IC401 (with the chip removed) are reasonably high and the main IC itself never got hot, so hopefully it survived. I'm waiting for my replacement IC401 to arrive...

If anyone has a working board and could take some measurements of the "correct" voltages in both the on and standby states, that would be great.

[Draco82]

Hello and welcome. I got the same model for repair. Initial Diagnosis no voltage on IC401, replaced with a new voltage returned to L408 - 1.8V L407 -1.2V. However, the monitor does not turn on. The rest of the voltages L405 - 3.3V, L601 - 5V, L602 - 19V, L410 - 0V (IC402 also replaced) Is it possible that the processor has failed? Current consumption 0.055A. No response to the switch, the status LED is off.

[lotas]

Yes, maybe the firmware has crashed here, maybe the processor, check the hdmi inputs, ... for a short or low resistance.

[Draco82]

Originally Posted by lotas

Yes, maybe the firmware has crashed here, maybe the processor, check the hdmi inputs, ... for a short or low resistance.

I made measurements on hdmi. All values ​​are normal, resistance high.

I took measurements in all possible places. The L408 has a fairly low resistance of 28 Ohms. I don't know if it's supposed to be that low.