Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

[bman4]

i got a 5351am sc that was working fine. i decide to just pull the buffers plugs and jump sc50 for a quick buffer diagnosis before i go to bed.

there was a loud pop then i notice ic 748/mip 391 along with front row igbt's shorted but did not pop.

center one in row closest to buffers 30f131,q623 read 19.00 ohms, i tested in diode and ohms there is 19-20 ohm short across sc2!

now i need to know if i just replace the ic 748/mip 391 ,30f131 ,q623 will it not pop again

i found the 20 ohom short on the ic 748 the correlates with the 30f131.

i removed the center igbt, 30f131,q623 and i reads good but started poking aorund the ic and found the 19- 20 ohoms.

unless im reading the 20 ohm resistor

the first row closest to buffer all still reads 00.19 short after removing center 30f131 q623.

i tested all resistors and diodes to test within spec.

the short on sc2 is gone since i removed the ic 748 and the pins cor-late with it

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

i did some more testing and found the RJP6364 RJP63G4 transistor shorted.

the rjp63g4 is a high voltage transistor located at the bottom

i ordered doubles just in case i hear another pop.

there seems to be two mip circuits and everything in the secondary values seem to match.


the top buffer was only shorted and i belive this is the one that corelates with it.


back in a flash,
bman4

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

just got finished installing the new ic 748/mip 391, 1 30f131, rjp63g4.

i jumped sc 50 without buffer this time and got the green light.

if anyone out there made the same mistake it's not impossible to repair.

i source my parts from china ebay sellers for cheap with great results.


sincerely,
bman4

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

now i got a serious delima on my hands.

i got a 2 black lines at the 13 pin of the top ribbion.

before i repaired a new su i powered it up without the second ic installed and got picture only at the top less than the usual amount of one ribbion and the line was not present.

installed ic and now full picture is present and so is lines.

the lines kinda do and kinda dont correlate with the only dead buffer ic or the one i replace but if you read what i said above its kinda like it dose.

i got these ic for as cheap as posible on ali exp and thpught i had a bad batch.

the tv has been runnng for 24 hours without a problem.

tried knocking flexing around connection with no results.

now i got good buffers from 50gt30 and wonder what part number to find to see if they are interchangeable.

can i use a 50 gt top buffer and a 50s bottom or do i need both ?

i seen the lines separate at one point or i might just bee seeing things.

thanks,
bman4

[diif]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

Either your IC is faulty or not soldered properly. Slight possibility the ribbon cable is damaged/not seated correctly.
There could also be another faulty buffer IC.

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

on the first buffer i repaired lifted a trace that was not in use and thought that was the problem because when i tested it in my first good panel i did not look at a full picture but just the input label, the rest was black .

this is the second buffer i repaired with the second from top ic toast and got the same result with the new one and figured it might be a chance of cheap ic's.

i check all pins for shirts and they are all solidly connected

just need to know about the 50gt30 buffer compatibility because i read something before but can seem to find it again.

thanks,
bman4

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

just went over the chip connections again with the soldering iron and problem is solved.

there still is ether a dirty connection or it's kinda burt in because it was sparkling blue and is a very faint grey now that get's better to the left.

wooohooo my panel is good


sincerely,
bman4

[diif]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

Good job.

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

after putting the back on and getting ready to put it up on the wall i decide to run image retention to try and get rid of some burnt in logos for the night.

as im cleaning up i come to notice the tv was off tried to turn it on an nothing.

un plug it for 30 mins and plug it in no light or blink at all.

test the power supply for stanby, no voltages, no blown fuse.

i found some green diodes and zener on the high voltage side that are showing reading both ways unlike other's but did not test out of circut.

might have to blow 100 and send it off to pts.

if i can get help finding the right value of these diodes and components i might be able to fix it for dollars.

might just have to do a clean sweep and replace all the small parts.

i might just buy a used one and repair this one myself to learn.

im guessing the low voltage control of the high side is shot from the surge of blowing up the sc.

i was waiting for a lcr meter for a year now for top tom electronic on ebay, the seller sent more , never arrived ,gonna buy from another.

going threw the whole board today and will check everything today, i will report with a picture of the components that test bad circled in red

back without a flash,

bman4

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

FAN6755UWMY

https://www.youtube.com/watch?v=DYQvNrsTsZ0

i wish my problem was as easy as in this video but im getting some weird reading both directions on diodes in circuit while others are fine one direction. i had a few in this list that are good one way but really high the other like i'm on a capacitor because im still in circuit.

d606,d604,d605,d609,d610,d702,d701,d601,d603,d602,d302,d303,d404,d402,d206,d202,d207,d201,d203,d253,d703,d354,d355

[bman4]

Re: Panasonic,p50s30 ,sc 5351am, forgot to isolate buffer screws.

got new used psu today and it back up and running.

i think i found the heat sinked double diode fof10a40/ rc351 to be bad!