Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Default LG 42V7 PDP firmware

Hi all.

Don't know if anyone can help with this. I have acquired a cheapo brand
Plasma TV with 2 faults. The most serious problem is that the picture is
very dark through all analogue inputs (aerial, SCART, VGA), it looks
similar to a lack of luminance signal (Y). HDMI input is fine, as are
the on-screen menus, so this is obviously a failure on the main PCB. If
I can solve the other issue below I will attempt to fault find this
board, but I have a feeling the main Digital signal processor is faulty
(the Genesis chip).

Anyway, more importantly the display has a very common fault as in
maldischarge (speckles) this is random all over the screen and
noticeable mostly on black areas or light to dark transitions. The
display is know for this problem (LG PDP42V7) I have a manual for the
PDP, have checked and replaced all electrolytics on the Y-SUS board with
no effect. Have also done a full set-up (Vs,Va,Vsc,-Vy and Vzb) as well
as the Vsetup and Vsetdown. Tried a few alterations as well to these
voltage levels, I have the display as good as it can possibly be. The
issue is not failure of either sustain board in this case, since both
waveforms conform to spec. The power supply is good and producing clean
voltage rails.

I believe this is a very common fault caused by ageing of the panel, and
LG supplied a firmware update for the control PCB to alter the timing of
the sustain waveforms to compensate. My problem, I don't have the LG jig
to apply the firmware. I know that a kit is available containing the
Y-SUS, Z-SUS and Control PCB's, however to me this is not a wortwhile
route considering the age of the set and the other (potentially
expensive) fault. I'm really only trying to repair this out of curiosity.

Does anyone know how I can apply a firmware update without the LG jig.
This is too old to allow an update via any service menu options, it
doesn't have any external ports such as USB or Common Interface either.
The firmware in this instance is applied directly to the control board
(there is a connector for the jig). In reading the service literature it
appears the jig connects to a parallel port on a PC and the firmware is
then downloaded onto the jig before being applied to the PDP. Any chance
I could construct something to do this? No doubt LG use some proprietory
interface for which no information is available.


I work for a major company and service Plasma equipment daily (much more
modern than this one!), the majority of this is warranty repair work. I
also have substantial repair experience as well as doing this for a
hobby. I have seen this type of fault many times, but in warranty repair
generally the entire PDP assembly is replaced. As I said I'm mainly
doing this out of curiosity. If I can't find a solution I will just
break the unit and sell the boards.

Apologies for the long message. Please do not reply with "replace the
boards/PDP, scrap the TV etc. type messages.

feel free to post this anywhere you think might help.
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Default LG 42V7 PDP firmware

On Sat, 28 Jan 2012 16:36:41 +0000, Clyde
wrote:

Hi all.

Don't know if anyone can help with this. I have acquired a cheapo brand
Plasma TV with 2 faults. The most serious problem is that the picture is
very dark through all analogue inputs (aerial, SCART, VGA), it looks
similar to a lack of luminance signal (Y). HDMI input is fine, as are
the on-screen menus, so this is obviously a failure on the main PCB. If
I can solve the other issue below I will attempt to fault find this
board, but I have a feeling the main Digital signal processor is faulty
(the Genesis chip).

Anyway, more importantly the display has a very common fault as in
maldischarge (speckles) this is random all over the screen and
noticeable mostly on black areas or light to dark transitions. The
display is know for this problem (LG PDP42V7) I have a manual for the
PDP, have checked and replaced all electrolytics on the Y-SUS board with
no effect. Have also done a full set-up (Vs,Va,Vsc,-Vy and Vzb) as well
as the Vsetup and Vsetdown. Tried a few alterations as well to these
voltage levels, I have the display as good as it can possibly be. The
issue is not failure of either sustain board in this case, since both
waveforms conform to spec. The power supply is good and producing clean
voltage rails.

I believe this is a very common fault caused by ageing of the panel, and
LG supplied a firmware update for the control PCB to alter the timing of
the sustain waveforms to compensate. My problem, I don't have the LG jig
to apply the firmware. I know that a kit is available containing the
Y-SUS, Z-SUS and Control PCB's, however to me this is not a wortwhile
route considering the age of the set and the other (potentially
expensive) fault. I'm really only trying to repair this out of curiosity.

Does anyone know how I can apply a firmware update without the LG jig.
This is too old to allow an update via any service menu options, it
doesn't have any external ports such as USB or Common Interface either.
The firmware in this instance is applied directly to the control board
(there is a connector for the jig). In reading the service literature it
appears the jig connects to a parallel port on a PC and the firmware is
then downloaded onto the jig before being applied to the PDP. Any chance
I could construct something to do this? No doubt LG use some proprietory
interface for which no information is available.


I work for a major company and service Plasma equipment daily (much more
modern than this one!), the majority of this is warranty repair work. I
also have substantial repair experience as well as doing this for a
hobby. I have seen this type of fault many times, but in warranty repair
generally the entire PDP assembly is replaced. As I said I'm mainly
doing this out of curiosity. If I can't find a solution I will just
break the unit and sell the boards.

Apologies for the long message. Please do not reply with "replace the
boards/PDP, scrap the TV etc. type messages.

feel free to post this anywhere you think might help.

One of the gentlemen who frequents the Badcaps forum
(www.badcaps.net/forum) has purchased the jig and is willing to
reprogram control cards for a fee. Unfortunately I don't remembe rhis
name, but it is likely that searching that forum for something like
'LG programming jig' will cause his name to pop up.

PlainBill
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Default LG 42V7 PDP firmware

On Sat, 28 Jan 2012 16:36:41 +0000, Clyde
put finger to keyboard and
composed:

Does anyone know how I can apply a firmware update without the LG jig.
This is too old to allow an update via any service menu options, it
doesn't have any external ports such as USB or Common Interface either.
The firmware in this instance is applied directly to the control board
(there is a connector for the jig). In reading the service literature it
appears the jig connects to a parallel port on a PC and the firmware is
then downloaded onto the jig before being applied to the PDP. Any chance
I could construct something to do this? No doubt LG use some proprietory
interface for which no information is available.


If the firmware is downloaded to an I2C EEPROM, then you could use
PonyProg freeware. All you would need to do would be to build a
trivial interface circuit.

Do you have a copy of the firmware? Do you have a circuit diagram of
the panel?

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.
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