Samsung LE22C451E2W Changing channels alone :D

[magneh]

Hello!

Well, this one is a funny one!
A friend on mine brought me this set. The problem is that when the TV turns on, it starts changing channels alone, from 1 to 99 .Doesnt respond to remote , neither touch keys.
It also changes volume, and it's impossible to change input etc.
Opened the set, power board is OK , all values OK.
Disconnected the ribbon from mainboard to touchpad, same behavior.

Mainboard - BN94-02707U code : BN41-01538A
Mesured values on CN401. Photo attached with labels.

TR- 3.3V
GND
A5V1- 3.31V
MSCL- 3.3V
MSDA- 3.3V
KEY1- 3.3V
KEY2- values changing from 0.6V to 2.6V (+-)
LED_STB - always changing values cant even read it

The LED is allways lighnting up when the cable is connected, as when it does when recieving remote commands, but in this case just by herself.

The A5V1 has only 3.3V, what seems to be a problem.
The value of key2 is the one promoting this behavior I suppose.
The other values seem OK to you guys?

The set was connected to antenna, so I removed the Tuner to check behavior.
Still persists.

Any one got any set with these kind of issues?
Or any suggestions?

[sordids999]

Re: Samsung LE22C451E2W Changing channels alone

Has the tv got side buttons for controlling the tv i had a 32 inch tv samsung recently that done the same disconnected this and the tv was fine

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

Has the tv got side buttons for controlling the tv i had a 32 inch tv samsung recently that done the same disconnected this and the tv was fine

Hello!

As I said before, disconnected the ribbon cable from mainboard to touch bouttons ...

Same thing...

[Shinju]

Re: Samsung LE22C451E2W Changing channels alone

Well if you disconnected the RF/Button control board and its still doing it I would say bad mainboard/eeprom.

check for loose soldier joints under the plug?

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

Well if you disconnected the RF/Button control board and its still doing it I would say bad mainboard/eeprom.

check for loose soldier joints under the plug?

Thanks for your feedback.
Yes, with RF/button CB disconnected, it does the same thing.

When you say under the plug, the plug of the RF/button board right?

Is the eeprom repairable/changeable?

Cheers!

[ecking767]

Re: Samsung LE22C451E2W Changing channels alone

Can you enter the menu and do a factory reset?

Can you do a rescan of the channels?

do you know the age of the TV?

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

Can you enter the menu and do a factory reset?

Can you do a rescan of the channels?

do you know the age of the TV?

Hello!

The set doesnt respond to remote comands neither buttons on the bezel.
Impossible to get to the menu, or rescanning channels.

The set has maybe 3 years.

Thanks!

[ecking767]

Re: Samsung LE22C451E2W Changing channels alone

this may not be an EEPROM issue, I will trace the keyboard input circuit, something maybe causing the circuit to behavior like a button is being press. an schematic will be very helpful, or simply replaced the main board will fix the problem.

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

this may not be an EEPROM issue, I will trace the keyboard input circuit, something maybe causing the circuit to behavior like a button is being press. an schematic will be very helpful, or simply replaced the main board will fix the problem.

Hello!

Seeing the price of a new mainboard, my friend doesnt look to keen to change it .
If I can find the fault, better, if not, I'm gonna talk to her and maybe scrap it for parts, if no other way.

The first thing I should do is find out why I'm not getting 5V on A5V1.
Anyne got any schematic?

Thanks!

[tom66]

Re: Samsung LE22C451E2W Changing channels alone

I can see at least two DC-DC converters (inductor+ceramic cap nearby is a good clue), the output of them can be checked. Any LDOs on the bottom of the board?

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

I can see at least two DC-DC converters (inductor+ceramic cap nearby is a good clue), the output of them can be checked. Any LDOs on the bottom of the board?

Hello!

Thanks Tom.
Here are 2 photos , top and bottom.
The inductor+ceramic cap , the DCDC converters , are those that I marked on the photo?

Later!

[magneh]

Re: Samsung LE22C451E2W Changing channels alone

Hello guys!

Am I going the right way?
Should I check these outputs marked on the photos?
Thanks for any inputs!

Cheers!

[carpamus]

Re: Samsung LE22C451E2W Changing channels alone

Resolveste o problema? Have you any Solution?
Estou na mesma situação. I've same problem.
Thanks

[mindfx]

Re: Samsung LE22C451E2W Changing channels alone

On key1 and key 2 , there is pull-up resistors , key 1,2 must have constatnt 3,2v to work , so mine problem was one of pull-up resistors , key 2 had only 0,4v , so it didnt works, put 1kohm to 3,3v , solved my problem of channel changing itself

[michael first]

Re: Samsung LE22C451E2W Changing channels alone

Hello,on pins #6 and #7 of the keyboard connector on the main board there are 2 diodes (on each one separately) connected to GND;remove them!

[Poca44]

Re: Samsung LE22C451E2W Changing channels alone

Hello,on pins #6 and #7 of the keyboard connector on the main board there are 2 diodes (on each one separately) connected to GND;remove them!

Hi, can you please mark them on the board where they are?
Thank you

[thesame]

Re: Samsung LE22C451E2W Changing channels alone

Hello,on pins #6 and #7 of the keyboard connector on the main board there are 2 diodes (on each one separately) connected to GND;remove them!

Are those diodes marked with CD2 and CD1 on the board near the main connector?

[cheeky2]

Re: Samsung LE22C451E2W Changing channels alone

I am amazed the the OP failed to tell us that the tuner board has been removed from the pcb! If the TV was turned on with the tuner selected all the outputs would probably give the results it did!
These boards suffer from tuning issues on Freeview which is a common issue which I guess why the tuning board was originally removed.
So anyone trying to solve the problem with this post is pretty useless! Especially when looking at the date it was originally posted.

Hello guys!

Am I going the right way?
Should I check these outputs marked on the photos?
Thanks for any inputs!

Cheers!

[nomoresonys]

Re: Samsung LE22C451E2W Changing channels alone

NO No, it's all good, he just relocated the tuner to the lvds cable.