LG 42LC7D serial control problem

fogled@mizzou

Hi all,

I was just wondering if anyone else has run into a serial control problem with an LG display recently. The one I have goes completely dead once I send it a power-off command, like the serial I/F ends up getting powered down too. I can't find any "fast on" setting on this one like Sony units that have a similar control issue. I also have another LG plasma display that uses the same command set, and works OK for power-up. I called and talked to LG, and I apparently have their engineers stumped for now.

Do any of you have any nifty ideas?

TonyAngelo

These are the codes I used for a 32LC7D, AFAIK they are the same as the 42.

LG_PWR_ON[] = {'k','a',$20,$31,$20,$31,$0D}
LG_PWR_OFF[] = {'k','a',$20,$31,$20,$30,$0D}

fogled@mizzou

TonyAngelo wrote:

LG_PWR_ON[] = {'k','a',$20,$31,$20,$31,$0D}
LG_PWR_OFF[] = {'k','a',$20,$31,$20,$30,$0D}

Yes, these are the same codes I'm using. But once I've issued the Power Off command, the serial interface goes completely dead, and won't respond again until I've powered the unit back on via the remote or the power button on the side.

Hedberg

Sometimes devices have a power save feature that disables RS232 when the unit is turned off.

According to an LG manual I have, there is a power saving feature that LG calls "Low Power." On is to save, off is normal. Check the OSD menus for the setting. The set that this manual belongs to has the low power option under the "Special" tab.

Also, the LG RS232 command list that I have says you can turn low power on and off and query with RS232. Best I can tell, these are the low power commands:

Low power off:

"'jq 01 00',13"


Low power on:

"'jq 01 01',13"

Low power status query:

"'jq 01 FF',13"

Chip Moody

Don't be surprised if you find that the "low/high" setting just adjusts the brightness of your display. In this case it's literally a setting for how much power the display consumes.

Unlike Sharp units, the power saving setting doesn't have anything to do with the RS232 port.

I've seen this discussed in another forum, and unfortunately haven't heard of a solution yet.

(Not counting "sell something besides LG")

- Chip

Hedberg

Chip Moody wrote:

Don't be surprised if you find that the "low/high" setting just adjusts the brightness of your display. In this case it's literally a setting for how much power the display consumes.

Unlike Sharp units, the power saving setting doesn't have anything to do with the RS232 port.

I've seen this discussed in another forum, and unfortunately haven't heard of a solution yet.

(Not counting "sell something besides LG")

- Chip

You're correct, no doubt. We've seen about a dozen of these over the last couple years and have never had this problem. Just wait, I suppose

Thorleifur

We sold about 20-30 LG monitors of different types last year and at least 3 did not respond to RS-232 commands after powering down. It all worked until beautifully during on site testing.. that is until the power down via serial.
Had to switch out those three and eat the cost of course. The replacements worked perfectly. LG had no answers!

Of course I should have posted something about this here instead of wasting time on phone calls to various LG engineers. Three instances is a bit much though. I have used Hitatchi, Sony and Samsung displays also, but never had problems, like this, with them.

TurnipTruck

I and several other major integrators that I know have decided to avoid LG. There is no other bias except our own first-hand experience with failures. Largely Garbage.

I know this doesn't solve your problem, but a large part of successful integration is equipment selection and sometimes you have to make blanket decisions for the sake of your time and reputation.

FYI, I use Panasonic, Pioneer and Electrograph plasmas in my designs and have had excellent results from reliability and control perspectives.

fogled@mizzou

Thorleifur wrote:

We sold about 20-30 LG monitors of different types last year and at least 3 did not respond to RS-232 commands after powering down.

This helps confirm my suspicion: it's a manufacturing defect. Some assembly line worker is probably plugging the RS232 module into the wrong power bus. A replacement should fix this problem.

Also taken to heart are the issues others have had. We've come to the same conclusion: stay away from LG if we can.

Thanks!