Panasonic P50G11B multiple problems

[Biruslapio]

Hello everyone,i've bought a defective P50G11B and was hoping to repair,i very much regret that decision now.This tv came from the depths of hell.

The previous owner apparently didn't mess with it,he took it to an repair shop to see what was broken,diagnosed A board.

When the TV got here it was blinking once every 3 seconds,i knew that meant "unknown error" or 5V standby missing,only A board plugged,all the P-board voltages were there,when i checked the A-board P25,all the pins were measuring 0V! I wasted some time before i discovered that of course,it was a damaged connector,ripped it off and soldered each and every wire directly into the board,it looks horrible but then green led and A-board was working,one of the fans was dead,i bypassed it with soldering the PWM wire to the other one and a 220 OHMs resistor between + and -,the power supply also had a bulging 220V 1200uF capacitor(VSUS),had to buy and replace that.

THEN when i connected everything and went to power up,loud buzz from the power supply,7 blinks,damn,SC-board,i took it out and found a shorted "2PG011" that was linked to VSUS,replaced with a weaker 30F124(should work),7 blinks again,found a shorted SMD diode,replaced,pushed the power button and BANG a poor IC exploded,M81707FP,inspected the board again,only to find 9 IGBTs and 4 drivers shorted,i just bought another board because there's no repair kits selling around here,it would be more expensive to buy the IGBTs than a new board.

New SC board came in,still 7 blinks,i was very upset to say the least.
Unplugged SD,6 blinks,was almost to the point of buying a SD+SU when i decided to unplug the lower C-board connector from A-board,then solid green led,but of course no display.

Plugged in C-board flat cable and it is displaying "8 blinks",now SS board?My patience was running out as i spent 10 hours fidgeting with that board,measured every resistor,replaced a M81707FP that seemed burnt,1 IGBT(45F127) and 2 driver ICs for that transistor,i think that it's killing the collector driver everytime i power up,because on diode mode between gate and collector there is no measuring,while on others on the board there is.

All that said,when TV turns on there is a quick buzz from the SS-board inductors,with the board disconnected from the panel or not doesn't matter,all the needed voltages(ve,tpSS1) appear for about 3 seconds then it disarms and slowly decreases,when the panel is connected tpSS1 jumps to 90V for miliseconds,does a crazy swing that my multimeter can't catch fast enough,drop to 37V and shuts down,VE goes to 135.6V(as the panel specifies) and shut down after 3 seconds too,VSUS,Ve and Vdat matches panel label(198V/135V/60V).

A-board,P-Board capacitor,a fan,SC board,SS board,so many problems.

Something i fear is a bad panel,shined a flashling and inspected it caurefully,nothing wrong,tried to power on horizontal or vertical,no difference.

I'm using the P50G10B service manual,all is identical except for the main board layout.
Just what is with this?someone can help me with the SS board?don't wanna just buy another one i've spent already half of what a working P50G11B is worth.

[tw2005]

Re: Panasonic P50G11B multiple problems

Hello everyone,i've bought a defective P50G11B and was hoping to repair,i very much regret that decision now.This tv came from the depths of hell.

The previous owner apparently didn't mess with it,he took it to an repair shop to see what was broken,diagnosed A board.

When the TV got here it was blinking once every 3 seconds,i knew that meant "unknown error" or 5V standby missing,only A board plugged,all the P-board voltages were there,when i checked the A-board P25,all the pins were measuring 0V! I wasted some time before i discovered that of course,it was a damaged connector,ripped it off and soldered each and every wire directly into the board,it looks horrible but then green led and A-board was working,one of the fans was dead,i bypassed it with soldering the PWM wire to the other one and a 220 OHMs resistor between + and -,the power supply also had a bulging 220V 1200uF capacitor(VSUS),had to buy and replace that.

THEN when i connected everything and went to power up,loud buzz from the power supply,7 blinks,damn,SC-board,i took it out and found a shorted "2PG011" that was linked to VSUS,replaced with a weaker 30F124(should work),7 blinks again,found a shorted SMD diode,replaced,pushed the power button and BANG a poor IC exploded,M81707FP,inspected the board again,only to find 9 IGBTs and 4 drivers shorted,i just bought another board because there's no repair kits selling around here,it would be more expensive to buy the IGBTs than a new board.

New SC board came in,still 7 blinks,i was very upset to say the least.
Unplugged SD,6 blinks,was almost to the point of buying a SD+SU when i decided to unplug the lower C-board connector from A-board,then solid green led,but of course no display.

Plugged in C-board flat cable and it is displaying "8 blinks",now SS board?My patience was running out as i spent 10 hours fidgeting with that board,measured every resistor,replaced a M81707FP that seemed burnt,1 IGBT(45F127) and 2 driver ICs for that transistor,i think that it's killing the collector driver everytime i power up,because on diode mode between gate and collector there is no measuring,while on others on the board there is.

All that said,when TV turns on there is a quick buzz from the SS-board inductors,with the board disconnected from the panel or not doesn't matter,all the needed voltages(ve,tpSS1) appear for about 3 seconds then it disarms and slowly decreases,when the panel is connected tpSS1 jumps to 90V for miliseconds,does a crazy swing that my multimeter can't catch fast enough,drop to 37V and shuts down,VE goes to 135.6V(as the panel specifies) and shut down after 3 seconds too,VSUS,Ve and Vdat matches panel label(198V/135V/60V).

A-board,P-Board capacitor,a fan,SC board,SS board,so many problems.

Something i fear is a bad panel,shined a flashling and inspected it caurefully,nothing wrong,tried to power on horizontal or vertical,no difference.

I'm using the P50G10B service manual,all is identical except for the main board layout.
Just what is with this?someone can help me with the SS board?don't wanna just buy another one i've spent already half of what a working P50G11B is worth.

I think had you not attempted repairing the SC you may have fixed it. I suspect when it went bang you've probably shot the sd/su boards.

This is what I'd do since you say you have a "new " SC board.


assemble it as normal except leave thee disconnected.

Disconnect the SD and Su from the SC(3 connectors) , removes the 4 silver Vfg bolts/screws. these are the ones that ground the buffers to the SC.

Now on the SC there is a small 2 pin connector with nothing in it labelled sc50.

Short those 2 pins together. Turn the TV on as normal.

Now if it turns on and the fans are spinning, then the 7 blink is the sd/su.

If it still does not and 6 or 7 then the SC is likely at fault.

the thing is though, you should still check and see if there are shorts between the output pins at the sd/su boards to the ground pad on the buffer Vfg(where those bolts were)

I've destroyed two sets myself testing a SC after repair and it going bang destroying both boards.

[Biruslapio]

Re: Panasonic P50G11B multiple problems

The bang occoured because all of the transistors of the floating voltage stage plus their drivers were shorted at some connections i didn't check them in all pins,it didn't affect the buffers because the SC had no chance to even work,i remember before it exploded VSCN was pulsating from 0 to 3V and back because it was disarming.

I did that SC50 jumper test with the new board AFTER i tested with the buffers plugged in,my mistake it could've killed the new SC,but i checked the SD and SU for shorts in many of the display output pins and almost every component before testing,no bad readings,but the board is really working fine,the TV boots even without that SC50 and no buffer,i don't know why,it should signal 6 blinks if no buffer and no SC50 short.

Then i only left the SC-board flat cable on the A-board and disconnected the C-boards,no errors,connected the SD+SU buffers,no error,green led and fans spin.And i said what?It was signaling 7 blinks before,maybe a buffer fixed itself or it was a poor connection.

After i did that test,put the C-board flat cables back to the A-board,all of a a sudden the 8 blinking appeared,and that's my problem right now,with the board either connected or disconnected from the panel same symptoms.

Checking the SS i found a discoloration spot,a bad soldering job at Q041(45F127) Gate pin,it's Gate and Collector driver(Q055 and Q056) were also really black together with a M81707FP(IC151) that was outputting to the driver,replaced all four(the 2 drivers + M81707FP + 45F127),still not working.If i unplug any cable from the SS it's back to 6 blink,so apparently it really is SS to me,no problems with any of the cables or connections i checked continuity.It lits up the green led,also outputs Ve and VSS with no problem for a short while,a short buzz is heard from the inductors at the top of the board when the 8 blinks appear.

Following the problem,i made a "very good" flow chart,it's probably inverted,something is happening that >>i think<< it is killing Q041 collector driver,it is not shorting,but makes it measure wrong,instead of 0.6V or 1.5V it is 1.7V G>C or E>C in diode mode,i'm not trusting in IC131(M81709FP),don't know how to test it,it costs 1/5 of a working SS board not even including the shipping.

I also sanded with 1200grit the ground and/or floating ground pads on SC,SU+SD buffers,SS and the panel backplate screws holder before any testing,they are all shiny now,cleaned the screws,this tv doesn't have the stupid ground problem but just for safety.

The service manual i got it at elektrotanya https://elektrotanya.com/panasonic_t.../download.html and goddamn i type too much.

[Biruslapio]

Re: Panasonic P50G11B multiple problems

Hey,update,i don't know what is wrong with this tv,but now it is powering on without the SS board,the panel fires up!And i can read "HDMI2" input,Main board,power supply,C-boards,SC are good to me,SU+SD are maybe.

But.
I'm sad now,there is 2 vertical reddish stripes at the panel,they were blinking and faded away after 10 seconds,then i shut the tv down,maybe they really died or fixed themselves,tried to hit the front glass in disappointment but didn't made much difference,please spare me from a PDP fault,damn i'm SO annoyed right now.

Is it safe to power it up without the discharge SS board?Want to check for vertical or horizontal lines,don't know about the SU/SD either,but if they didn't kill the SC yet means that none of them are defective?

EDIT:The stripes were probably lack of warmup,as they are gone now,got some courage(wow!!1!),just turned the TV on and went to antenna connection,the whole screen is fine,except that there is a problem with 2 horizontal lines,and i know why,this tv was rotting in a heavily humid ambient,there was oxidation everywhere,mostly at the panel cables that goes to SU,i cleaned them but some connections were just torn,now i think i'll have to ninja solder a wire from the really fragile cable connection that is broken to the buffer,that will be fun,it'll kill the SC+buffers if i do anything wrong.