coby LED 2326 will not turn on

[CR Designs]

Picked this TV up, The Tv will not turn on .It has a blue led light on in the right hand corner that comes on when you plug it in. If you hit the power button again the light gets brighter for a second when the tV shuts off. All the voltage is right on the power board 5v and 12v. On the main board the powers are right for 12v and 5v but the 3.3v is not right. It is measuring 5.27v

[budm]

Re: coby LED 2326 will not turn on

Where is that 3.3V test point? Is it under that long board attached to the power supply board?
I see the connector on the left side of the board where it has 3.3v label on it, so it must be 3.3V regulator or buck regulator on the main board.

[CR Designs]

Re: coby LED 2326 will not turn on

Where is that 3.3V test point? Is it under that long board attached to the power supply board?

Budm I tested it on the main board at the plug marked 3.3v

[budm]

Re: coby LED 2326 will not turn on

Can you trace that back to the connection on the power supply board since I can only the the connector labeled with 5V and 12v OUTPUTS. There must be a regulator some where that drops the 5V down to 3.3V.
I see at least two 3-leg regulators on the main board.

[CR Designs]

Re: coby LED 2326 will not turn on

Can you trace that back to the connection on the power supply board since I can only the the connector labeled with 5V and 12v OUTPUTS. There must be a regulator some where that drops the 5V down to 3.3V.
I see at least two 3-leg regulators on the main board.

budm, I can't trace it. here's a few more pictures. let me know if you need more

[selldoor]

Re: coby LED 2326 will not turn on

Coby!! I thought they made trouser presses!!
U21 is an adjustable VR - can you test it -you have had lots of practice with those.
Also what is the value of the little attached resistors.


EDIT sorry that is Corby

[selldoor]

Re: coby LED 2326 will not turn on

Budm did say trace it on the power supply (not sure if that is what he meant) but you have posted pics of the main board.
Can you do a close up of the other VR and on the power supply a pic from the side
showing all the legend for the connector and another shot of the back of the power supply
as the bit needed to trace back from the pin is flashed out.

ALSO what is the black blodge by the other connector on the main board has something died there - can you clean it off with isopropyl alcohol. There is also another streak in the last 3 opics can you clean that off as well in case it has gone conductive.

None conductive stuff and dust heat up and if they get to the point where they oxidize or start to burn it can turn to carbon which is conductive.

[CR Designs]

Re: coby LED 2326 will not turn on

Coby!! I thought they made trouser presses!!
U21 is an adjustable VR - can you test it -you have had lots of practice with those.
Also what is the value of the little attached resistors.


EDIT sorry that is Corby

selldoor, do I test u21 with power on or off? I will be posting more pictures soon. The brown stuff your seeing on the board i think is glue. I will try and get it off

[budm]

Re: coby LED 2326 will not turn on

Power on, I think one of those regulator is for the 3.3V.

[CR Designs]

Re: coby LED 2326 will not turn on

Budm did say trace it on the power supply (not sure if that is what he meant) but you have posted pics of the main board.
Can you do a close up of the other VR and on the power supply a pic from the side
showing all the legend for the connector and another shot of the back of the power supply
as the bit needed to trace back from the pin is flashed out.

ALSO what is the black blodge by the other connector on the main board has something died there - can you clean it off with isopropyl alcohol. There is also another streak in the last 3 opics can you clean that off as well in case it has gone conductive.

None conductive stuff and dust heat up and if they get to the point where they oxidize or start to burn it can turn to carbon which is conductive.

Here's more pictures of what you wanted selldoor.

[selldoor]

Re: coby LED 2326 will not turn on

Ok - U20 is the 3.3 volt VR but what part numbers are the two on the back U3 and U4

Also in pic4 just above R29 there is a black spot between two traces - is it just debris?
can you remove it and check the traces are not bridged.

[CR Designs]

Re: coby LED 2326 will not turn on

Ok - U20 is the 3.3 volt VR but what part numbers are the two on the back U3 and U4

Also in pic4 just above R29 there is a black spot between two traces - is it just debris?
can you remove it and check the traces are not bridged.

Part numbers
U3 3251 R64 11051
U4 ME 15N10

R29 was nothing just something on the board

[selldoor]

Re: coby LED 2326 will not turn on

U4 is a mosfet
https://cdn.badcaps-static.com/pdfs/...33c86bdf36.pdf

There is something before 3251 ? on U3 two letters?

[CR Designs]

Re: coby LED 2326 will not turn on

U4 is a mosfet
https://cdn.badcaps-static.com/pdfs/...33c86bdf36.pdf

There is something before 3251 ? on U3 two letters?

Looks like it could be II or 11

[CR Designs]

Re: coby LED 2326 will not turn on

Coby!! I thought they made trouser presses!!
U21 is an adjustable VR - can you test it -you have had lots of practice with those.
Also what is the value of the little attached resistors.


EDIT sorry that is Corby

Selldoor, tested U21 and U20

U21 Tab-1.2v, pin 1-3.3v, center pin- 3.308v, pin 2- 000.1v

U20 tab -3.206v, pin1-2.02v, center pin-3.201v, pin 2-5.14v

[selldoor]

Re: coby LED 2326 will not turn on

Ok so still 5v on that pin marked 3.3? Can you trace back from that pin to either of these
VRs

[CR Designs]

Re: coby LED 2326 will not turn on

Ok so still 5v on that pin marked 3.3? Can you trace back from that pin to either of these
VRs

Yes still 5v

[tom66]

Re: coby LED 2326 will not turn on

All too often I have encountered errors on labels -- engineers in a rush to finish by 5pm?
(That happened today and I realised I forgot something important but luckily I can easily sort it out Tuesday...)

[CR Designs]

Re: coby LED 2326 will not turn on

Guys, here's more picture's I can't trace this board. May be these will help.

[tom66]

Re: coby LED 2326 will not turn on

Good news is, neither can we. This board will use at least 4 layers meaning two hidden between the top and bottom. More likely it will be 6 layers making it even harder.