Ysus_zsus

[lot2learn]

Have anyone got the schematics for any of these especially for the LG,I know that LG do not supply them but I have heard That someone has one directly from lg Technician, (Can not remember his name)
Tv set is 50px4d-eb.... green light but black raster, they may be a problem on micro board, also, found that the 115 vset voltage was zero due to faulty mosfets on Buffer board 45pn15 (150V@45A) rdson 33miliOhms, replaced mosfets on top buffer board, lower biffer board disconnected yet still blank screen,with upper board connected
but the 115V is now there, I think there is a problem with the y sus drive waveform as there isnt a negative goingtransition to prime the cells, theres a dc offset,
would like to have a schematic on this...thanks

[cadiman]

Look up threads on L/G and you will find alot of info here. Your panel is on scribd.com and look through L/G training manuals. I have used this website for all of my L/Gs and I remember seeing your panel number. All of your specs are on the white sticker on the back of the pdp top right or top left. The L/G manual will tell you where to check for volts. Good luck! I am bad about this, but everyone here likes pictures It helps us help you. Good Luck!
Cadiman

[lot2learn]

Thanks for reply me and my colleague have found that one of the IPM modules are bad, removed it from circuit for repair both of the IGBT have popped as well as a 2r2 and shorted T6790 (complementary high gain transistors)
Ive managed to find equivalent IGBT (gb10nb37lz) going to replace them and module should be ready to go, I am not going to buy another board when repairing the module looks straight forward

[cadiman]

I am sure you can handle it. If you look at old threads you will see I break off the plastic ic at the screw, remove the heat sink then cut the pins one at a time Then un-solder each pin with a butane iron and install the heat sink after I solder the chip in.
( use 6/32 allen bolts and washers and nuts. This is nice if you need to go back in or re-solder or replace.
I have found good used z boards cheap, but the y sus are still cheaper to repair.
Make sure to check all caps around the heat sinks these ics run very hot.
Cadiman

[lot2learn]

thanks i will check those capacitors, replaced mosfet on buffer boards, and replaced the IPM y sus module from spare, unit, repairing the older one at a later date, we had a shorted flash chip, unsolder and resoldered,
TV up and running at moment on soak test,
cheers