Samsung LN32C530F1FXZA No Power, No Standby Light

[tomcat15]

Hello Badcaps,

I have a Samsung LN32C530F1FXZA that is showing no standby light, and will not power on (including backlight).

The TV showed no signs of failing until this issue.

This is my first time attempting TV repair and would appreciate any guidance.

Here's what I've found so far. Please excuse the crude schematic:

1. TCON===Control=XXX=Power Supply===BL Inverter

a. Backlight Turns On

2. TCON==XXX=Control===Power Supply===BL Inverter

a. No Power, or Standby

3. TCON===Control===Power Supply===BL Inverter

a. No Power, or Standby

I have visually inspected all Caps and could not identify any bad Caps based on visual inspection alone.

I took DC Voltage readings from the Power Supply with Control disconnected please see attached image of pin diagram.

1(B13V)-12.28 2(5V_DET)-. 02
3(B13V)-12.28 4(BLU_ON)- 5.2
5(B13V)-12.28 6(E-PWM)- .92
7(GND)-0 8(H-SYNC)- 0
9(GND)-0 10(GND)- 0
11(B5V)- 5.24 12(GND)- 0
13(B5V)- 5.24 14(B5V)- 5.24
15(B13V)-12.28 16(A5V)- 5.24
17(B13V) - 12.28 18(PS_ON)- .78

As I understand, the Power Supply should provide ~5V standby power, which appears to not be happening.

My elementary guess is a problem exists on the Power Supply or Control. What steps can I take to determine which board is malfunctioning?

Thank you all very much for your help!

[Nick's Tvs]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

if you don't get 5 volts out of your power supply then you have a bad PSB.
If I were you, I would take a voltage measurement on the large filter capacitor on your power supply. DC volt setting, black lead on negative side, red lead on positive side.
Be very careful, very high voltage going through that cap, practice first so that you don't accidentally have a lead slip, and short out something.
You should get 160 when the tv is off in standby, and about 380 when the set is on. If you don't get any reading, then check your fuse, check your power cable, check the plug you are using to make sure it works properly, and check your inductors. I have gotten a few samsung power supplies with bad inductors lately.

[budm]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

'16(A5V)- 5.24' You do have 5VSTBY, A5V is the stby Voltage.
Yo also have switched B5V, B13V whcih are turned on by the PS-ON signal which you need to recheck if it is really 0.78V which is too low to turn on the switched B5V, B13V circuit.
How about uploading some pictures of the whole boards?

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

if you don't get 5 volts out of your power supply then you have a bad PSB.

Hi Nick, if you see the reading from original I am getting some pins at 5.24 V. I've see a lot of Samsung boards online with "Standby" somehow labeled on the pin legend. Can't find it on this board. I do notice 5V_DET is reading .02 (is this the standby?)

If I were you, I would take a voltage measurement on the large filter capacitor on your power supply. DC volt setting, black lead on negative side, red lead on positive side.
Be very careful, very high voltage going through that cap, practice first so that you don't accidentally have a lead slip, and short out something.
You should get 160 when the tv is off in standby, and about 380 when the set is on.

Thanks for the heads up. Looks like I neglected a shot of the full power board, I apologize. Please see attached where I measured. I believe that was what you were referring to. 169-170V.

I'm unable to turn the set on so I couldn't verify the 380 reading.

If you don't get any reading, then check your fuse, check your power cable, check the plug you are using to make sure it works properly,

Checked fuse using continuity test on meter - Good.
Power Cable - Visually inspected, Good
Plug - Metered and ~120V AC

and check your inductors. I have gotten a few samsung power supplies with bad inductors lately.

I had to google inductors. Are these the loops of copper wire close to the AC?
On my board they're labeled 630110S.

As far as testing, do I perform a resistance test with the meter? Do I need to remove them from the board?

Thank you!

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

'16(A5V)- 5.24' You do have 5VSTBY, A5V is the stby Voltage.

Thank you very much budm, I suppose that is in line with the logic that 5VSTBY is next to PS_ON. Just couldn't find a source on google to confirm that.

Yo also have switched B5V, B13V whcih are turned on by the PS-ON signal which you need to recheck if it is really 0.78V which is too low to turn on the switched B5V, B13V circuit.

I measured the voltages with the Control disconnected. Will I need to have the Control connected when I measure?

How about uploading some pictures of the whole boards?

Thank you for pointing this out, I realized I neglected two. Power Board shot is in my reply to Nick's post. Control Board Attached. Thanks!

[budm]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

BTW, Do you get 24V on the other power supply output connector?

I would like to see the Voltage readings with all the cables back in place.

Power supply board: BN44-00339B
http://www.shopjimmy.com/samsung-bn4...upply-unit.htm
Sch attached.

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

BTW, Do you get 24V on the other power supply output connector?

With all boards connected, 0 V at the other connector. With Control disconnected, 24.2 V reading on all power pins

I would like to see the Voltage readings with all the cables back in place.

Pin 16 (A5V) - 5.24V
Pin 18 (PS_ON) - .02V

All other pins read 0V.

What are your thoughts? Thanks!

[budm]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

The main board is not sending the PS-ON to turn on the PFC Voltage booster circuit to boost ehDCV on the main filter cap from 160VDC to close to 400VDC which the 24V SMPS requires to work, also not turning other switched Voltage as well.

The thing is that your power supply board has pull-up resistors to force on the power supply and the backlights so it can do the self test of the power supply by disconnecting the cables between the main board and the power supply board, if you do not get around 400VDC on the main cap and no 24V for the backlights inverter to run, then you have power supply problem to begin with.
So please verify again when no cable between power supply and the main board, do you have 400vdc and 24v, and backlights?
BTW, what is the history of this TV, someone work on it before you, hit by surge, etc?

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

The main board is not sending the PS-ON to turn on the PFC Voltage booster circuit to boost ehDCV on the main filter cap from 160VDC to close to 400VDC which the 24V SMPS requires to work, also not turning other switched Voltage as well.

The thing is that your power supply board has pull-up resistors to force on the power supply and the backlights so it can do the self test of the power supply by disconnecting the cables between the main board and the power supply board, if you do not get around 400VDC on the main cap and no 24V for the backlights inverter to run, then you have power supply problem to begin with.
So please verify again when no cable between power supply and the main board, do you have 400vdc and 24v, and backlights?

Please see the attached picture, I want to ensure "main filter cap" is what is referenced in the picture. Disregard text on the picture, I'll measure voltage again and verify those 3 items as requested.

BTW, what is the history of this TV, someone work on it before you, hit by surge, etc?

Wife's TV since 2010ish to present. No previous history of repair. I can't rule out power surge, but has been plugged into surge protector. All other electronics in the house work just fine. TV failure was a surprise to us, didn't show any signs beforehand.The only thing that may be worth mentioning is for the past 2 years we've had a Roku stick attached in the HDMI. This requires external power source. Plugged into same outlet.

[CapLeaker]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

That cap you circled is the main filter cap. If the PFC is working, you should have >360v DC there

[budm]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

Please see the attached picture, I want to ensure "main filter cap" is what is referenced in the picture. Disregard text on the picture, I'll measure voltage again and verify those 3 items as requested.



Wife's TV since 2010ish to present. No previous history of repair. I can't rule out power surge, but has been plugged into surge protector. All other electronics in the house work just fine. TV failure was a surprise to us, didn't show any signs beforehand.The only thing that may be worth mentioning is for the past 2 years we've had a Roku stick attached in the HDMI. This requires external power source. Plugged into same outlet.

That is the main filter cap, measure right between the two legs.

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

That cap you circled is the main filter cap. If the PFC is working, you should have >360v DC there

Thank you CapLeaker, found it OK

That is the main filter cap, measure right between the two legs.

Setup 1: Main Board disconnected

Main Filter Cap - 390V, BL Voltages 24.2 V, and visually confirmed back lights on.

Setup 2: Main Board connected (immediately after Setup 1)

Main Filter Cap - Voltage dropped --2V / sec until reaching 169V. BL Voltages all 0, visually confirmed back lights off.

[budm]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

OK, the main board is not sending the PS-ON.

[ReeceyBurger123]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

Bad main board then, common issue is corrupt epprom/firmware.

[tomcat15]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

OK, the main board is not sending the PS-ON.

Bad main board then, common issue is corrupt epprom/firmware.

OK I see, thank you both for the guidance! Is there a way to test for a bad EPPROM?

I wouldn't know how to check firmware

[CapLeaker]

Re: Samsung LN32C530F1FXZA No Power, No Standby Light

you can try freezing it with a can of air upside down, then turn the TV on.