toshiba plasma 42hp66 sound ok no picture

[shelby5041]

hi

sound ok no piucture at all screen black

voltages good from ps
no visual bad aps on y or z
no visual burns on y buyffer chips

tested large fuses on y and z......y board both fuses good....z board 1 OPEN FUSE

powered tv on for 15 min....y board heat sink very hot to touch....z board heat sink just barely luke warm...not hot at all but not stone cold definitely its doing something since its luke warm

i have seen where if the chip on the y or z gto bad they are stone cold but in this case the z board heat sink is not stone cold....is luke warm normal?? if the chip is bad can it sill put out heat//???


any ideas?

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

would it be ok to replace the fuse and see how tv acts to pinpoint issue or could that cause more damage to tv?

i was thinking of didconnecting y to protect it and replacing z fuse and try to power on tv.....

is this a safe option to try

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

note...when i pull out good fuse and check for continuity touching both ends of metal ends in fuse socket where fuse goes i get no reading as expected

but when i pull out open/blown fuse and check for continuity at metal ends in fuse socket where fuse goes i actualyy get continuity.....how can that be? and what does this mean?.....board shorted somewhere?

[mmartell]

Re: toshiba plasma 42hp66 sound ok no picture

Yes means short circuit. If you pull the ipm on the zsus I bet your short disappears.

[mmartell]

Re: toshiba plasma 42hp66 sound ok no picture

Wait I just reread that. A better test is to unplug the harnesses to the zsus then test fuse socket to a ground screw. Neither should show continuity and if it does then see my post above.

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

hi

without a fuse in the socket ...if i touch both ends of metal mount area i should get no continuity at all period

but i do get continuity in the socket that had an open fuse

regardless of any cables connected or not there should be no continuity at all without a fuse in the socket

correct?

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

and now that i removed the stk chip on the z board the continuity in the open fuse socket went away

so im pretty sure there as a short in the circuit....

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

i have the board out of tv now so cant do that test

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

one question i do have is i removed the stk chip out of the board....using unconventional way since i dont have proper tools.....since i wasnt able to desolder it off due to two sided board and lead solder...i cut it out using a dremel tool and surgically removed it....but i ruined a few copper pads on top of board...can someone tell me if these pads are important .... here is a pic of z board with stk chip removed and i left the legs..

and was not able to remove the inductor copper coil....like budm said its almost impossible to remove but i was able to remove stk without removing it ....couldnt melt the solder since much of the heat just went through the whole coil and not where i wanted it to go

i hate lead solder and i hate double sided boards when trying to remove components....

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

here is a pic marked with pads that have been ruined...

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

hi update

i ordered a used z board on ebay .did some basic testing on it..fuses good and ipm is not shorted out....original z had open fuse and ipm tested shorted so i assume it needed a new z board..installed it today and tv still not working'

originally i said there was no picture in my post but actually there is a slight real grainy partial picture ...i had tv in bad location couldnt see very well when i originally started troubleshootiung......'

'i have taken pics with the replacement z board plugged in and without it plugged in and there isnt much difference.....any ideas??

the y board fuses are good and the large heat sink get hot when tv on....havent done any testing on y board since the fuse on z was bad and ipm shorted i figured thats 100% the issue...even coppell tv thought it was when i called them...

could the z board i bought be bad even though ipm tests not shorted and fuses ok..or is there some other multiple issue going on

the partial picture is very very grainy and little pinkish and the display area starts small when tv turned on and seems to get a little larger after a few minutes it like expands...but then stops ...

i would like to get this tv fixed if anyone can help me out...

the first pic is with replacement z board installed and 2nd pic with z board unplugged

[ReeceyBurger123]

Re: toshiba plasma 42hp66 sound ok no picture

Looks like Zsus to me again. This is a reason why I always repair sustain boards than buying used ones you never know what you are getting. Possible that the ipm on the Ysus if it uses one could also be toast if there is anyway you could replace the ipm on the Ysus and possibly check the Zsus over for loose joints ect.

[Shinju]

Re: toshiba plasma 42hp66 sound ok no picture

I stopped working on these Toshiba/LG plasma panels they are spendy to repair and 9/10 times you have to replace both IPM's on y/z ect. Also you will probably need to flash the controller board to the latest firmware and that is a pain and the only person I know who has the jig to do it is CapKid.

These are decent picture for an old 720p plasma but if you are fixing to flip they do not sell and more then likely it's at a loss.

The 50" are even worse! 2 IPM's per sustain boards!

If you are going to replace 1 IPM I would just go ahead and do both.

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

thanks.......as said the fuse on z was blown and ipm tested shorted thats why i replaced z board......but since z was used....no guarantees its good.....

i didnt mess with y since fuses good and ipm was gettung hot when tv on

yes plasmas are a pain to diagnose.....and parts very costly for this model....

is there anythung i can test on y.....?

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

and if i unplug y board and leave z pkugged in i get no picture at all.......screen is 100% black

[ozy]

Re: toshiba plasma 42hp66 sound ok no picture

going by the pics I would say replacement z-sus is faulty.

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

ok...also does it matter if i dont mount z board with all screws i just mounted using 2/6 screws.......for testing.......thos shouldnt affect anything right?

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

with replacement z board plugged in and y board disconnected ...i touched heat sink on z after tv on 5min...and it was cold.....is this normal?

the power supply has power cables going to y and z individually so y disconnected should not affect power to z

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

and i dont have the proper equip to remove the ipms.....they are a pain....double sided board metal on both sides...and lead free solder....impossible to desolder with what i have

[shelby5041]

Re: toshiba plasma 42hp66 sound ok no picture

ok correction....the heat sink on replaxcement z does get warm once i have the y board connecrted also .............it stays cold is y board not connected .......anyways

i ordered another used z sus..will see how what happens....i know 2 people think its a zsus issue ....since original z sus ipm was shorted and blown main fuse...it only makes sense to assume its a zsus problem

however how can i be sure its not a ysus or y buffer issue?

why is it so hard to troubleshott symptoms to either y or z or y buffer?

just by what tv is doing and how picture is there is no way to tell which board is the issue???

doesnt weach board do something specific enough to tell or do they all work together and really no way to tell ?