panasonic tx-p50x50b

[piccy]

Re: panasonic tx-p50x50b

Hi Tw2005
thanks for the information i will produce a documented list of values and post
the results

I did test last night round the heatsinked components some showed a little different reading but nothing strange (i didnt think anyway) i did notice a reading of 2.2ohms across cap 842 (there is a 2.2 resistor close by and from what i can see is connected to it, the cap also reads quite high ESR 0.8 , am looking to see if i have anything lying around i can subs it with, the in circuit ESR of c813 is also quite high at 0.5 i will take that one out and check it again, its high voltage may have to order some if you think they may be the cause.

just made a quick check across vfg to vfo and get the same 2.2 ohm reading as across cap842

anyway i will do the checks all again and document properly

If you wish to move this to a new thread please do , i am new to forums so not sure fully how they operate so apologies for that.

[tw2005]

Re: panasonic tx-p50x50b

Hi Tw2005
thanks for the information i will produce a documented list of values and post
the results

I did test last night round the heatsinked components some showed a little different reading but nothing strange (i didnt think anyway) i did notice a reading of 2.2ohms across cap 842 (there is a 2.2 resistor close by and from what i can see is connected to it, the cap also reads quite high ESR 0.8 , am looking to see if i have anything lying around i can subs it with, the in circuit ESR of c813 is also quite high at 0.5 i will take that one out and check it again, its high voltage may have to order some if you think they may be the cause.

just made a quick check across vfg to vfo and get the same 2.2 ohm reading as across cap842

anyway i will do the checks all again and document properly

If you wish to move this to a new thread please do , i am new to forums so not sure fully how they operate so apologies for that.

I'm not admin but I get confused easy following original thread about PSU then someone else jumps in and then you started with 7 blink which is totally unrelated.

So definitely 2.2 ohms? not 2.2 megohms or K ohms?

If 2.2 ohms, I think we may have found it since I would expect megohms. that is checking the buffer section of the board which is shorted by the sounds of it. If so then the board is unrepairable.

very hard to get manuals and impossible to read the schematics in these . I'll see if i can see any thing of note. I'd forget about caps being the issue

[tw2005]

Re: panasonic tx-p50x50b

Hi Tw2005
thanks for the information i will produce a documented list of values and post
the results

I did test last night round the heatsinked components some showed a little different reading but nothing strange (i didnt think anyway) i did notice a reading of 2.2ohms across cap 842 (there is a 2.2 resistor close by and from what i can see is connected to it, the cap also reads quite high ESR 0.8 , am looking to see if i have anything lying around i can subs it with, the in circuit ESR of c813 is also quite high at 0.5 i will take that one out and check it again, its high voltage may have to order some if you think they may be the cause.

just made a quick check across vfg to vfo and get the same 2.2 ohm reading as across cap842

anyway i will do the checks all again and document properly

If you wish to move this to a new thread please do , i am new to forums so not sure fully how they operate so apologies for that.

I'm not admin but I get confused easy following original thread about PSU then someone else jumps in and then you started with 7 blink which is totally unrelated.

So definitely 2.2 ohms? not 2.2 megohms or K ohms?

If 2.2 ohms, I think we may have found it since I would expect megohms. that is checking the buffer section of the board which is shorted by the sounds of it. If so then the board is unrepairable.

very hard to get manuals and impossible to read the schematics in these . I'll see if i can see any thing of note. I'd forget about caps being the issue

If Vfo has gone short to gnd, looking at the schematic what you say makes sense.

Is this your TV and it just failed or a project?

[piccy]

Re: panasonic tx-p50x50b

tw2500 just clarify what you said re checks in case i have misread what you wrote (aplogies if i have)

"""there is a test pad VFG & VFO. Check resistance between those and vfg - vf5v"""

i have measured between the two pads VFG & VFO (which rises to 2.2ohms as if being charged by a cap) are you meaning between each of those and gnd ? if so its in the mid to high kohms when measuring each pin to gnd

just a note all test points on the board you mentioned inc srv p5v and srvp15v and sr vsus all measure in kohms to gnd

a friend brought it to me its his , it had gone off a couple of times on him in past just left it unplugged and next time he tried it it worked , this time when it went off it didnt come back on , it was a learning project now as he gave up and bought an lcd tv , would like to use it as a challenge and if i get it going have got me a free 50" plasma in the process , if cant will strip it and bin rest. Beginning to think it may be the panel itself thats faulty

[tw2005]

Re: panasonic tx-p50x50b

Hi Tw2005
thanks for the information i will produce a documented list of values and post
the results

I did test last night round the heatsinked components some showed a little different reading but nothing strange (i didnt think anyway) i did notice a reading of 2.2ohms across cap 842 (there is a 2.2 resistor close by and from what i can see is connected to it, the cap also reads quite high ESR 0.8 , am looking to see if i have anything lying around i can subs it with, the in circuit ESR of c813 is also quite high at 0.5 i will take that one out and check it again, its high voltage may have to order some if you think they may be the cause.

just made a quick check across vfg to vfo and get the same 2.2 ohm reading as across cap842

anyway i will do the checks all again and document properly

If you wish to move this to a new thread please do , i am new to forums so not sure fully how they operate so apologies for that.

ridiculous at 5 quid . parts are worth more. trusting you don't have a cracked or shorted panel and this part is ok.

http://www.ebay.co.uk/itm/PANASONIC-...-/181640108830

[tw2005]

Re: panasonic tx-p50x50b

Hi Tw2005
thanks for the information i will produce a documented list of values and post
the results

I did test last night round the heatsinked components some showed a little different reading but nothing strange (i didnt think anyway) i did notice a reading of 2.2ohms across cap 842 (there is a 2.2 resistor close by and from what i can see is connected to it, the cap also reads quite high ESR 0.8 , am looking to see if i have anything lying around i can subs it with, the in circuit ESR of c813 is also quite high at 0.5 i will take that one out and check it again, its high voltage may have to order some if you think they may be the cause.

just made a quick check across vfg to vfo and get the same 2.2 ohm reading as across cap842

anyway i will do the checks all again and document properly

If you wish to move this to a new thread please do , i am new to forums so not sure fully how they operate so apologies for that.

tw2500 just clarify what you said re checks in case i have misread what you wrote (aplogies if i have)

"""there is a test pad VFG & VFO. Check resistance between those and vfg - vf5v"""

i have measured between the two pads VFG & VFO (which rises to 2.2ohms as if being charged by a cap) are you meaning between each of those and gnd ? if so its in the mid to high kohms when measuring each pin to gnd

just a note all test points on the board you mentioned inc srv p5v and srvp15v and sr vsus all measure in kohms to gnd

a friend brought it to me its his , it had gone off a couple of times on him in past just left it unplugged and next time he tried it it worked , this time when it went off it didnt come back on , it was a learning project now as he gave up and bought an lcd tv , would like to use it as a challenge and if i get it going have got me a free 50" plasma in the process , if cant will strip it and bin rest. Beginning to think it may be the panel itself thats faulty

any chance you can take a photo of the meter with the 2.2. make sure i can see the whole meter.I can't imagine a meter rising to 2.2ohms. It would get there in an instant so something is not right.

it's vfg-vfo, vfg-vf5v not normal gnd. Vfg is floating gnd for the buffer section. often if the bffer is short vfo -vfg will be short

[tw2005]

Re: panasonic tx-p50x50b

is the board screwed down tight(all screws),and try a reseat of sn20

[piccy]

Re: panasonic tx-p50x50b

will get you an image in next half hour

images attached , hopefully you can see enough in pictures i tried to take from not connected (ol on meter to final value takes about 2 seconds )

[tw2005]

Re: panasonic tx-p50x50b

will get you an image in next half hour

hope i can stay awake, intermittent 7 blink then permanent sounds interesting. might have to see if we can verify it's definitely triggering at the Sn and not a misdetection on the A board.

[piccy]

Re: panasonic tx-p50x50b

have just posted you images above your last post , yes screws were tight read that on another post first thing i tried (wishfull thinking )

sn20 been in and out 3 times very careful when putting back

i am going to see what power rails i get ie 15v when it powers green before it goes blinking red again

[tw2005]

Re: panasonic tx-p50x50b

in my opinion , replace the SN board. that's dead short. weird but maybe the cap was causing that. I'll just have a quick look for another guide to see what to expect for TP SN1 but I've got a 2010 SN board and vfg to vfo is showing in cct up to 1 meg but not stable.

[tw2005]

Re: panasonic tx-p50x50b

try vfg - sn1 resistance , I think it's off an inductor

** actually it's clear and off one end of that 2.2ohm resistor

also, set meter to buzzer or diode and put one probe on the vfg, and then slide the other along the face of all the pins at the panel ribbon connectors to see if a short shows there.

[piccy]

Re: panasonic tx-p50x50b

will try suggestions,

regards try vfg - sn1 resistance about 4 ohms rising like on the vfg - vfo

i think i am going to risk £20 (£5 plus carriage) for the board on ebay , its peanuts if it cures it , if it dont it dont then i will strip it for the boards

It would have been good to find the fault at board level but sometimes theree is no gain, we'll see what the replacement board does.

thanks for all your time its appreciated , just out of curiosity have you a circuit for this ?

If you have a sudden brainstorm on this do let me know

[tw2005]

Re: panasonic tx-p50x50b

will try suggestions,

regards try vfg - sn1 resistance about 4 ohms rising like on the vfg - vfo

i think i am going to risk £20 (£5 plus carriage) for the board on ebay , its peanuts if it cures it , if it dont it dont then i will strip it for the boards

It would have been good to find the fault at board level but sometimes theree is no gain, we'll see what the replacement board does.

thanks for all your time its appreciated , just out of curiosity have you a circuit for this ?

If you have a sudden brainstorm on this do let me know

you did not like the 5 pound board?

no, not really. found a 42xt50 with sn board so cct could be similar but the detail is too poor and honestly I think it's the buffer ICs that have shorted so no point getting down to that level of repair. TPSN1 confirms bad too and I was expecting short which it is.

Sn board failure, all going well it comes back to life with a new board.

I've brainstormed enough to get this far.

[piccy]

Re: panasonic tx-p50x50b

have just measured between vfo and the opposite end of the 2.2 ohm resistor (not the test point end and i get 0.1 ohms near enough to a short to me , so i reckon you are right and the fault is in the buffer section

yes it was the board you sent me link to £4.99 , not being in uk they want an extra £15 for delivery

thanks again for your help , knowledge gained

[tw2005]

Re: panasonic tx-p50x50b

have just measured between vfo and the opposite end of the 2.2 ohm resistor (not the test point end and i get 0.1 ohms near enough to a short to me , so i reckon you are right and the fault is in the buffer section

yes it was the board you sent me link to £4.99 , not being in uk they want an extra £15 for delivery

thanks again for your help , knowledge gained

Oh, ok that's my ignorance , Shopjimmy has about 500 new boards at 19USD but shipping would probably blow it out. let's hope that board is ok. it is very cheap

[tom66]

Re: panasonic tx-p50x50b

I think I have a 42" board here I can test...

[sordids999]

Re: panasonic tx-p50x50b

well i was going to close this thread to say i replaced the 6755U IC and tv is all working now but another topic has replaced it so....

but thanks for all your help guys

[drussell]

Re: panasonic tx-p50x50b

well i was going to close this thread to say i replaced the 6755U IC and tv is all working now but another topic has replaced it so....

but thanks for all your help guys

Another 6755 strikes again!

I'm glad that was the only problem and you fixed it, thanks for reporting back!
I have been watching this thread for a success report to the original topic before it got hijacked. It seems like this is going to be a very common failure.

[tw2005]

Re: panasonic tx-p50x50b

well i was going to close this thread to say i replaced the 6755U IC and tv is all working now but another topic has replaced it so....

but thanks for all your help guys

Another 6755 strikes again!

I'm glad that was the only problem and you fixed it, thanks for reporting back!
I have been watching this thread for a success report to the original topic before it got hijacked. It seems like this is going to be a very common failure.

yeah, sorry tried to encourage a new thread to be started. I think because there was no other topic mentioned in the title other than the model, it appears this is a thread on any fault for that model.

I'd close it anyway. Pretty messed up now.