Samsung LE40C530F1W Sound No Screen

[Glowstone]

Hi all..

(I bet the TV techs get sick of this kind of thing)

I have the above LCD TV and there is no screen. The start up chime plays fine though.

I have replaced 11 main caps on the power board and checked both glass fuses that check out fine.

Any thoughts on what I can test next?....could it be the lighting controller/ circuitry is dead?...what sort of money are those?

many thanks

Martyn

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

[ReeceyBurger123]

Re: Samsung LE40C530F1W Sound No Screen

Read some of the other threads on this set ?

[dick_barton]

Re: Samsung LE40C530F1W Sound No Screen

When you look at the back do the tubes light up which you should see through the holes in the rear chassis.
With a strong light and after the chimes press menu and scan the screen to see if you can see the menu being displayed on the panel in the background. You have to move the light around the screen and look carefully.
If you have a menu next plug a dvd player into the scart socket since these usually do not need you to select in the menu and see if you have sound when you play a disc.
If all those work then you have a backlight problem.

If none of the above work then take all the voltage readings you can and report them back.
EG
Con1
Pin 1 (label) standby voltage) Out of standby

Pin1 (+5V) 0V +5V
etc

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

Many thanks..

I have tried to force start the backlights by removing pin 6 on the top row of the 18 pin connector to the logic board..nothing happened.

I just looked to see if I could see any dim images or glows to the side and there isnt anything there.

I am unsure where to start testing pinouts?

Thanks again!

[CapLeaker]

Re: Samsung LE40C530F1W Sound No Screen

2nd picture left side. We need all voltages on the connector with the corresponding pin out name, tv on and tv off.

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

Sorry for the late reply...

here are my readings

Pin STDBY-v ON-v

1. 0.00 12.89
2. 0.00 0.47
3. 0.00 12.89
4. 0.00 2.85
5. 0.00 12.89
6. 0.00 1.29
7. GND
8. 0.00 1.75
9. GND
10. GDN
11. 0.00 5.25
12. GND
13. 0.00 5.25
14. 0.00 5.25
15. 0.00 12.90
16. 5.25 5.26
17. 0.00 12.89
18. 3.00 3.96



I accidentally hit the chassis with my needles and the TV seemed to restart..I am guessin thats a protect function....

many thanks for your time!

[budm]

Re: Samsung LE40C530F1W Sound No Screen

Sorry for the late reply...

here are my readings

Pin STDBY-v ON-v

1. 0.00 12.89
2. 0.00 0.47
3. 0.00 12.89
4. 0.00 2.85
5. 0.00 12.89
6. 0.00 1.29
7. GND
8. 0.00 1.75
9. GND
10. GDN
11. 0.00 5.25
12. GND
13. 0.00 5.25
14. 0.00 5.25
15. 0.00 12.90
16. 5.25 5.26
17. 0.00 12.89
18. 3.00 3.96



I accidentally hit the chassis with my needles and the TV seemed to restart..I am guessin thats a protect function....

many thanks for your time!

Where are the pin names so we can tell what the Voltage readings are for.

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

Sorry

Name Pin on off

B13V 1. 0.00 12.89
5V DET 2. 0.00 0.47
B13V 3. 0.00 12.89
BLUON 4. 0.00 2.85
B13V 5. 0.00 12.89
EPWN 6. 0.00 1.29
7. GND
HSYNC 8. 0.00 1.75
9. GND
10. GDN
B5V 11. 0.00 5.25
12. GND
B5V 13. 0.00 5.25
B5V 14. 0.00 5.25
B13V 15. 0.00 12.90
A5V 16. 5.25 5.26
B13V 17. 0.00 12.89
PS-0N 18. 3.00 3.96



Many thanks

[budm]

Re: Samsung LE40C530F1W Sound No Screen

BN44-00340B diagram.
https://www.badcaps.net/forum/showth...ht=BN44-00340B

So are you getting close to 400VDC between the two legs of the main filter cap?

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

Thanks budm

I am a novice to this as you can guess..

which one specifically would be the filter cap?...there are 2 large yellow caps here as in the other posts.

What is the safest way to test these for the voltages you mention?

[budm]

Re: Samsung LE40C530F1W Sound No Screen

Pictures provided by shopjimmy.
You can choose either one of the two large yellow caps.

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

329v standby
325v power on

I take it thats not a good look!

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

Ok I have also tested diode DP801 and in Diode test mode it reads 519 when negative to negative and infinity when reversed....

DP805 reads 527 negative negative and infinity when reversed

[budm]

Re: Samsung LE40C530F1W Sound No Screen

DP801, 805 are right next to each other.
https://www.badcaps.net/forum/attach...2&d=1466630101

[budm]

Re: Samsung LE40C530F1W Sound No Screen

BTW, you should show the straight shot pictures of the whole power supply board that I can read the part designators, the one from SJ is Revision 1.2, yours is 1.1

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

DP801, 805 are right next to each other.
https://www.badcaps.net/forum/attach...2&d=1466630101

yes I just spotted that..its been a long day here sorry about that

DP805 reads 527 negative negative and infinity when reversed

heres a front pic..did you want a closer shot of anything or of the back also?

many thanks

[budm]

Re: Samsung LE40C530F1W Sound No Screen

As long as those two DIODES are not shorted then they are OK, if they are shorted then you will not get the 400VDC boosted Voltage.
So now you need to check if the PFC IC to find out if it has DCV between VCC and GND pin when PS-ON is present.

[Glowstone]

Re: Samsung LE40C530F1W Sound No Screen

I think the diodes are ok..

so I need to bring the supply out of "stand by"... and test the ground pin of CN802 with black probe...and the collection of power with the red probe...

which is the best point to test the collection...would that be at the diodes anode?

[budm]

Re: Samsung LE40C530F1W Sound No Screen

you are making the measurement in the HOT DEADLY side of the circuit, the GND is the negative leg of the main filter cap.
You need to locate the PFC Controller IC to find out which one is the VCC pin, see schematic for details.
The IC is SMD and mounted on the bottom side of the board so it is not going to be easy checking the Voltage during live test.