LG 60PS11 (plasma) no picture

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Ok, just took out buffer boards instead. Was easier. Both Vsc and -Vy voltages dropped to 0.04 VDC ish.

[tom66]

Re: LG 60PS11 (plasma) no picture

That's with the power supply connected to the Y-sustain?

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Yes it is. All power connected, buffer boards removed. I will leave on for ten minutes and check agin. I will also double check voltage to Y-SUS board

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Checked again. 196 VDC coming in on VS, 68 on VA, nothing on test points for -Vy and Vsc.

[tom66]

Re: LG 60PS11 (plasma) no picture

This would seem to indicate your Y-sustain is faulty, then.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Ok I will order one and replace it. I will keep you posted. Thanks for the help.
For future reference, should the voltages at the test points for -Vy and Vsc be similar to VA or VS voltage? Or what is the relationship between the two?

[tom66]

Re: LG 60PS11 (plasma) no picture

-Vy is typically in the -100V to -200V range, Vsc is typically in the (-Vy+50V) to (-Vy+150V) range. The exact values are listed on the plasma panel sticker and indicated in the service doc I linked you.

[j_rigsby]

Re: LG 60PS11 (plasma) no picture

Ok real good. Thanks again for sharing your knowledge. Much appreciated.

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

Hi i have the exact same trouble with exact same panel . But seems like y-sus of this tv are rare now . Mine dont energize at al but have sound , y sustain humm like normal one , z- sustain humm too and i can hear the noise change if i pop up osd !
All voltages look good exept VSC and -VY who are both ~4/10V)

I have dismounted all heatsink on y sustain than checked all t0-220 with an atmega 168 based device tester ( ebay)

on heatsink labeled HS401
Heatsink contain 7 x 51n25 (51A 250v)
4 of them reported as NE-MOS
3 reported as diode (farted)
(Dont have any 51amps so i have replaced all 7 by 7x irf14229 (38A) so i have added 3 more on an extra heatsink

Heatsink HS805
Contain 2x RF2001 and 4X 45F122

All 4 45f122 reported as capacitor ( farted)
Replaced by 4 x 45g127

Heatsink HS 804
Contain 2xRF2001 and 4x 45F122
All parts on it was good

HS702 AND HS703
each contain 4X RF2001 and 2X 45f122
All parts on it reported good

The last heatsink contain 2X K3453 and reported good

All big surfacrmount diodes report good in diode mode DMM

All resistors at gate of transistors are good

I will update further the progress of my work

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

there it is '' the thing''

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

also with both y-buffer boards removed VSC and -VY voltages are ~4/10V
i will test most regulator on the board today and make an update

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

what i have checked at this time in this sector

in red its relults with tv plugged and on

in yellow its reading with setup OFF and unplugged

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

Im not just sure if its a good idea to put my multimeter on dc and probe my IGBTs while the set running to see whish section does not work maybe i will find whos not pushing current or simply not switching on

Like black probe on the frame and red probe on g/d/s

[heavymachines]

Re: LG 60PS11 (plasma) no picture

You can test without power. In diode mode with dmm.

[dick_barton]

Re: LG 60PS11 (plasma) no picture

What is the part number for IC906

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

What is the part number for IC906

The part is labeled RSS090

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

Oh wow a switching power mosfet , and my vsc not switching on..

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

You can test without power. In diode mode with dmm.

Yess in fact i have removed all heatsink with parts on it then tested each one , replaced 4X 45F122 blowed open and reported as a capacitor and 3x 51n25 blowed open and reported as a diode between drain/source .

All transistors are actually good , there is a failed gate driver on this board and i dont know where , so if i probe source /drain in each stage of the sustain i will be able to determine wich one have no power or simply not switch on .but i fear the power in these board lol i dobt want to toutch the drain of an igbt and see a electric ball of light

[Jeff Pepin]

Re: LG 60PS11 (plasma) no picture

What is the part number for IC906

man thanks ive just do some readings with black probe on frame , and it look like this mosfet are not switching on ,

if im ok in knowledge with a working fet ,when applying 2v to the gate it will switch on and the 5.0V from the drain will pass thru the source right ?
in this case the 5.0V not pass thru ,

option a 1,9V is not enought

option b the switch is toast