Skyworth 24E22 no power

[yobbgsm]

Hi Mates,

I am new to TV repair, looks fascinating to me. This is no power at all, no standby light. Can someone help me figure out what's the issue of this 24" led tv I am working with? What I noticed is there was no voltage on DC (12V, 24v) part of transformer, not sure if the transformer is defective? I already tried to replace the mosfet even I know it is still good, diodes also had good reading.

Please help.


Thank you.

[dick_barton]

Re: Skyworth 24E22 no power

If you put your meter probes on M7 (black lead) and M8 (red lead ) and check what DC voltage is there when the set is plugged in (approx 160V DC) and on and when you come out of standby.
Be careful since that's the live side of the power supply connected to the mains electricity supply.

[thoma]

Re: Skyworth 24E22 no power

https://www.youtube.com/watch?v=uN1fNQGhyyM

http://www.skyworthservice.com/2014/...-skyworth.html

What is the name of your SMPS Power supply any sticker with name or
numbers?
168P-P24? stand on the white sticker but can not read

[yobbgsm]

Re: Skyworth 24E22 no power

If you put your meter probes on M7 (black lead) and M8 (red lead ) and check what DC voltage is there when the set is plugged in (approx 160V DC) and on and when you come out of standby.
Be careful since that's the live side of the power supply connected to the mains electricity supply.

Hi,

I will look into it later and will post result, thank you for you response.

[yobbgsm]

Re: Skyworth 24E22 no power

https://www.youtube.com/watch?v=uN1fNQGhyyM

http://www.skyworthservice.com/2014/...-skyworth.html

What is the name of your SMPS Power supply any sticker with name or
numbers?
168P-P24? stand on the white sticker but can not read

Hi,

I will look into it later and will post result, thank you for you response.

[yobbgsm]

Re: Skyworth 24E22 no power

Hi dick_barton,

I am getting 298 DC volts on M7 M8, (Capacitor) is that normal?

@thoma,

it's 168P-P24EQB-W1
5800-P24EQB-WP00

Thanks mate.

[thoma]

Re: Skyworth 24E22 no power

http://tel-spb.ru/remont-tv-lcd/supra-stv-lc24t820fl

scroll down until
Скачать: Схема Chassis MSD309B Schematic diagram.
download this schematic of power supply inside

[dick_barton]

Re: Skyworth 24E22 no power

Hello Thoma, Unfortunately the schematic does not appear to match the power supply shown in post #1

[thoma]

Re: Skyworth 24E22 no power

SUPRA STV-LC24660FL
Chassis: 5800-A8M280-OP10
Panel: HM236WU3-100
T-con: HM236WU1-100 X0.0
Inverter: integrated into PSU
Inverter IC: OB3362HP
Inverter FET:ME15N10-6
Inverter Trans: IVTEL 1900033 1036
Power: 168P-P24EQB-W2 - 580-P24EQB-WP10
Power IC: OB2273 (6pin)
Power Fet: JCS4N65F
MAIN: 5800-A8M280-OP10 Ver10.00
IC Main board: FLASH: Q32B-104HIP; SOUND: 1517 (20pin)
Tuner: ET-9Z2E-CF106H
Remote: RC13b

[dick_barton]

Re: Skyworth 24E22 no power

Hi dick_barton,

I am getting 298 DC volts on M7 M8, (Capacitor) is that normal?

@thoma,

it's 168P-P24EQB-W1
5800-P24EQB-WP00

Thanks mate.

What is the voltage rating as written on the capacitor. I would have though the voltage read on the capacitor would be higher, maybe at 390V.

[thoma]

Re: Skyworth 24E22 no power

http://televid-sib.ru/index.php?topi...27050#msg27050

[yobbgsm]

Re: Skyworth 24E22 no power

Hi dick_barton,

It says 450V, 68uF. Thank you.

Will look into schematic thoma, thank you.

[thoma]

Re: Skyworth 24E22 no power

https://cdn.badcaps-static.com/pdfs/...8b2a6bf076.pdf

[yobbgsm]

Re: Skyworth 24E22 no power

https://cdn.badcaps-static.com/pdfs/...8b2a6bf076.pdf

Hi thoma,

Looks like you are referring to the IC behind the board, so after checking all, seems to me that IC was the problem. This is very helpful in my troubleshooting experience.

[thoma]

Re: Skyworth 24E22 no power

Does your power supply react to heat and freeze?
Take a hair dryer and push the warm air to the power supply and the mainboard
the same do with freeze spray
Reaction?

[thoma]

Re: Skyworth 24E22 no power



datasheet OB3362RP

[dick_barton]

Re: Skyworth 24E22 no power

Hi dick_barton,

It says 450V, 68uF. Thank you.

Will look into schematic thoma, thank you.

Looking at the back of the power supply photo in post #1 it says 300V so your voltage looks fine. There is also 17V marked on the board which you can check it is there.

There are a lot of solder joints (red boxes) that need to be soldered again that can be seen on the back of the board.
Have you checked both fuses.

What is the value of the resistor in the yellow box

[thoma]

Re: Skyworth 24E22 no power

http://manualbase.ru/index.php?do=fi...file&lid=48419

schematic stv-lc24660

[thoma]

Re: Skyworth 24E22 no power

small lcd like this 24 inch do not have a pfc circuit
therefore the voltage at the big capacitor is about 300V
in greater lcds more than 32 inch there is a pfc circuit
so the voltage on the big capacitor is about 400V
you can see it in the schematic if there is no pfc
the big capacitor is directly behind the Bridgerectifier
if there is a pfc there is a pfc ic a power mos fet a powerdiode
a inductivity before the big capacity
google pfc circuits
regards thoma

[yobbgsm]

Re: Skyworth 24E22 no power

Looking at the back of the power supply photo in post #1 it says 300V so your voltage looks fine. There is also 17V marked on the board which you can check it is there.

There are a lot of solder joints (red boxes) that need to be soldered again that can be seen on the back of the board.
Have you checked both fuses.

What is the value of the resistor in the yellow box

Hi dick_barton
Those are the joints that I de-soldered when I off the circuit the mosfet and diodes on the other side. Both fuses are good. I will check the resistor later. Thank you for your patience.