qn75q70rafxza suiciding samsungs

[lotas]

Re: qn75q70rafxza suiciding samsungs

What is the general resistance between 1(3.3v) and 4(GND), is it not low?

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

well every things possible... he can use cool spray to freeze it.... then turn on... if the 30 second BL on increase... if so will be funny case

Bl doesn't come on at all anymore, not even 30 sec.

What would I try to freeze?

Lotas 2.4kohm 1 and 4

[Diah]

Re: qn75q70rafxza suiciding samsungs

Pt9801

[Diah]

Re: qn75q70rafxza suiciding samsungs

or try by pass it with short circuit..

[lotas]

Re: qn75q70rafxza suiciding samsungs

You need to determine how and what is assembled on these three channels, what voltages they have at their terminals, and what transistors they are.

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

Will do lotas, will report back in about 4 hours

[Diah]

Re: qn75q70rafxza suiciding samsungs

one things more.. if PT9801 (a PTC Thermistor as we thought ) and there swollen at the middle of the surface it will be in cutoff always.

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

one things more.. if PT9801 (a PTC Thermistor as we thought ) and there swollen at the middle of the surface it will be in cutoff always.

Pt9801 has 3 ohms resistance so multi meter shows short because almost no resistance

There is 1.408 v coming in and 1.408v leaving

[Diah]

Re: qn75q70rafxza suiciding samsungs

1.408v you have also on pin 1 9802 ?

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

1.408v you have also on pin 1 9802 ?

Yup

Pin 1 shows continuity to both right and left side of pt9801 it shows no resistance continuity on right side on left side it shows 3 ohm resistance so almost continuity just low resistance. All 3 points show 1.408 v

[Diah]

Re: qn75q70rafxza suiciding samsungs

Yup

Pin 1 shows continuity to both right and left side of pt9801 it shows no resistance continuity on right side on left side it shows 3 ohm resistance so almost continuity just low resistance. All 3 points show 1.408 v

did you read my post #56 ??
you need to free one leg of PT9801... to let Pin 1 zero V. and then we feed Pin 1 with 3.3V... i wrote an example... but you can use any source on TV like power on.... but in this case need to connect it via R 1K

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

did you read my post #56 ??
you need to free one leg of PT9801... to let Pin 1 zero V. and then we feed Pin 1 with 3.3V... i wrote an example... but you can use any source on TV like power on.... but in this case need to connect it via R 1K

So can I just pull pt9801 off the board then feed pin 1 the 3.3v? I don't know how to free it otherwise. And I will need to buy some resistors I see you say jump 3.3v with 1k all the time but I don't have one. Maybe scrap board. Okay will try tonight

[Diah]

Re: qn75q70rafxza suiciding samsungs

So can I just pull pt9801 off the board then feed pin 1 the 3.3v? I don't know how to free it otherwise. And I will need to buy some resistors I see you say jump 3.3v with 1k all the time but I don't have one. Maybe scrap board. Okay will try tonight

sure you can take it out... but dont lost it..lol... after take it out u need to test to see the v you read before on which side in and if pin 1 ready to be 0v.

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

Okay I didn't get into all the exactness of it but installed new led driver board and it's working fine. Points 1 and 2 as established run at 3.1v as picture shows.

Thx story, lotas and diah and anyone I may of missed.

[Diah]

Re: qn75q70rafxza suiciding samsungs

,,,,,,

[lotas]

Re: qn75q70rafxza suiciding samsungs

why you sold it to him,,, at time you can install power boards and main boards on yours ??? just the LED socket need new configuration at wiring !!

Diah, what are you talking about?

[Diah]

Re: qn75q70rafxza suiciding samsungs

lol.... wrong

[EazyBone]

Re: qn75q70rafxza suiciding samsungs

Diah, what are you talking about?

Yes lol diah.

[Diah]

Re: qn75q70rafxza suiciding samsungs

Yes lol diah.

No, i post 2 time over here... but they were thought to another threat.... Lotas give me the attention so i delete them.

[KYBOSH]

Re: qn75q70rafxza suiciding samsungs

I would love to know what was wrong on the old board.
Not sure if you buttoned up this TV yet but if not (and it were me) I would be probing and comparing to see where the fault was. An SMD or an IC.