panasonic th-50u30a no blink code

[attainteddragon]

hi guys, this pana has an orange stand by light when plugged in and no response when it gets it's on signal from the remote.

i have 4.88v on the standby pin (pin 6 of p6), and .5v on pin 7 (f stby on) but no other voltages are present on any other pins.

i do have 15v present at at d003 and d004 (just above the relays)
also at pc401, pc502 and pc 501 (opto's)

the main filter cap gets up to 320v and slowly drifts off till a relay clicks and the voltage is temporarily brought back. during the loss of voltage, the relay squeaks lightly like a rusty spring compressing.

i get no on signal, so no pfc.

i only get 40v ac at the bridge rectifier.

on d006 and d011 (next to the upper coil), i get 330v

with ps out (mpf6910), i have 240v up to the relays, but that is as far as i seen to get to at this point.

any help would be greatly appreciated.

[tw2005]

Re: panasonic th-50u30a no blink code

Have you checked the SC board yet for short cct on SC2? Or check the 30F131 IGBTs for short but dead short on Sc2 I'd check first

[attainteddragon]

Re: panasonic th-50u30a no blink code

i have isolated sc board and it is 7.5 m on sc2
just checked the 30f131's and they are all good

i have also isolated the ss board and the resistance on ss11 was good, but can't remember the numbers off of the top of my head.

[tw2005]

Re: panasonic th-50u30a no blink code

i have isolated sc board and it is 7.5 m on sc2
just checked the 30f131's and they are all good

i have also isolated the ss board and the resistance on ss11 was good, but can't remember the numbers off of the top of my head.

Bugger, a real fault then. They can lock out and present no error blinks or response to the remote with a shorted SC.

I guess you've tried waking it using the side buttons on the TV?

Does it ever attempt a startup or at plugin do you get the typical relay clicks and then after 30secs they reset?

I'm just reading the original post again as I was assuming this was going to be a typical SC short.

I do have A 50U30 with the back off as a testing mule if you want some points checked , just ducking out for 20mins

[attainteddragon]

Re: panasonic th-50u30a no blink code

yeah, i think it may be a real fault. i didn't know about the non responsiveness of remote, i'll have to remember that.

yeah, i have tries the side buttons, no love there.

there appears to be no real sign of a start up. vs, va never even try. just a single click from one of the relays every 30 odd seconds, then voltage slides away.

some reference would be awesome.

i'm thinking that if i can get the main filter caps back on target, then it should be all good.

[tw2005]

Re: panasonic th-50u30a no blink code

The US ST30 looks equivalent board wise. The training guide give some info on the sequence of the startup but relay clicking every 30secs, I wonder if it's a mainboard issue?

[attainteddragon]

Re: panasonic th-50u30a no blink code

just had a look through the guide (nice one too).

standby 5 should feed to ic5000 on the a board, generate 3.3 and 1.2v to ic8000
then feed back to the p board through pin 7 of p6, and since i am only getting .5v ( i'm guessing that it is the 1.2v that should be there)on there, it could be the main board.

my only concern is why is my voltage on the main filter caps, so erratic?

[attainteddragon]

Re: panasonic th-50u30a no blink code

am i able to isolate the ps and jump it on to check it?
i.e. pin 6 (stb) to pin 7 (f stby on) to see if the 15 volt rail come up and potentially the rest of the rails?

[tw2005]

Re: panasonic th-50u30a no blink code

power boards are not a strong point of mine although I've had to fault find a couple recently and got lucky.

I've never forced a Panasonic P board on but I'm sure you can, I don't want to make any suggestions but there should be a few other guys that have that may have some tips.

I don't think 1.2v is pin7 P6.

I would not jump 5V unless you know that is correct,

I'll see if I can back probe pin7 p6 and see what happens

[tw2005]

Re: panasonic th-50u30a no blink code

i can't get a reading, seems to be same level as gnd and thats at plugin, turning it on with the switch or remote on and off

[tw2005]

Re: panasonic th-50u30a no blink code

am i able to isolate the ps and jump it on to check it?
i.e. pin 6 (stb) to pin 7 (f stby on) to see if the 15 volt rail come up and potentially the rest of the rails?

I was reading The “TV_SUB_ON” command is provided to pin 5 of connector P6 of the power supply to develop the F15V.

[attainteddragon]

Re: panasonic th-50u30a no blink code

i will have a go over mine tomorrow when i have better lighting.

http://www.datasheetq.com/view.jsp?p...asonic&lang=en

this is the pinout of ic5000
i will see if i can find the 15v on switch from here as well. can't hurt.

are you saying that pin7 goes low on start up?

[tw2005]

Re: panasonic th-50u30a no blink code

i can't get a reading, seems to be same level as gnd and thats at plugin, turning it on with the switch or remote on and off

I'll have to recheck this, eyes are so bad I was on pin 15 for pin 1!

[tw2005]

Re: panasonic th-50u30a no blink code

i will have a go over mine tomorrow when i have better lighting.

http://www.datasheetq.com/view.jsp?p...asonic&lang=en

this is the pinout of ic5000
i will see if i can find the 15v on switch from here as well. can't hurt.

are you saying that pin7 goes low on start up?

just going for another look, got the pins wrong

[Moreno83]

Re: panasonic th-50u30a no blink code

These models can give weird faults. I repaired the same model this week with the same boards.
These "cheaper" models suffer from mainboard problems because of bad cooling. They usually come with "14 blinkers".

If you only measure 5V on P6 and no other voltages ( 15V etc ) then the mainboard does not turn on the tv.
Do you have voltages on P34 ( I believe ). You must measure 5v there.


These sets also give almost instant green blink when they turn on. Thats a SC board failure.

My guess is that you have a bad mainboard. BGA solder failed.

[tw2005]

Re: panasonic th-50u30a no blink code

just going for another look, got the pins wrong

At plugin in standby that is with the main power button in, Pin 7 is 3.1v, relay energises, f15v on pin 10,11. After a good 30secs left in standby maybe more the relay de energises and the pin7 3.1v has gone low(0V), F15v gone

[attainteddragon]

Re: panasonic th-50u30a no blink code

p34 and p35 read nothing at all.

i will see if i can work out if the signal is getting to ic5000 to ic 8000 and then back.

wish i had the coin for an ir rework station, well, one day.

so it should be feasible to jump the ps on to check the 15v rail, but ill look through the main board first.

[tw2005]

Re: panasonic th-50u30a no blink code

p34 and p35 read nothing at all.

i will see if i can work out if the signal is getting to ic5000 to ic 8000 and then back.

wish i had the coin for an ir rework station, well, one day.

so it should be feasible to jump the ps on to check the 15v rail, but ill look through the main board first.

That's normal. P35 is Vda and that's not going to happen until panel on. P34 is simply going to the switch and grounds when the switch is on so won't be any voltage there, none on mine

[tw2005]

Re: panasonic th-50u30a no blink code

If you're forcing the PSU, I would have it fully isolated , the last thing you want is a voltage to come on and damage say the panel. maybe a load on vsus like 240V bulbs?

[attainteddragon]

Re: panasonic th-50u30a no blink code

i'll see what i can find on the p7 signal path.

tw, if you isolate the ps on yours, is the main filter cap voltage stable?