Samsung - no standby - already replaced all caps but still

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

Sorry I did not notice page 2... see below...

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

I have just checked these....

VAC in - 220V (correct European voltage)
VAC in middle pins of rectifier - 220V
VDC out of Rectifier all the way to the Main Capacitor is 305V.

So I assume this means that the bridge rectifier needs replacing as I am sure it was around 325 VDC earlier today.

[CapLeaker]

Re: Samsung - no standby - already replaced all caps but still

Nope. rectified 220V: 220x1.414=311.08V
So all is ok.

[budm]

Re: Samsung - no standby - already replaced all caps but still

For me to trace out why you are not getting the standby Voltage, I will need REALLY WELL FOCUSED pictures of the bottom side of the power supply to see how the circuits are laid out.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

Nope. rectified 220V: 220x1.414=311.08V
So all is ok.

That is what I am getting. 311V at the main capacitor but I can confirm at the std-by pin (pin 3) there is no voltage.

What next to check after the main capacitor?

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

For me to trace out why you are not getting the standby Voltage, I will need REALLY WELL FOCUSED pictures of the bottom side of the power supply to see how the circuits are laid out.

Is the attached any good?

[budm]

Re: Samsung - no standby - already replaced all caps but still

Check the resistance of the Fusible resistor RB806, you know how to test the resistance, right? No power to the unit!
BTW, I need straight shot picture of the top side of the board becuause your BN44-00208B is NOT the same shown at shopjimmy.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

Check the resistance of the Fusible resistor RB806, you know how to test the resistance, right? No power to the unit!
BTW, I need straight shot picture of the top side of the board becuause your BN44-00208B is NOT the same shown at shopjimmy.

To check resistance... I assume without power and DMM set to ohms. Do I need to remove it from the circuit.

Will send you photo later - I have to reopen TV.

[budm]

Re: Samsung - no standby - already replaced all caps but still

To check resistance... I assume without power and DMM set to ohms. Do I need to remove it from the circuit.

Will send you photo later - I have to reopen TV.

Just check the resistance between the two legs of that resistor, TV not plugged into the outlet, meter set to 200 Ohms range if it has manual setting.
If it is in auto range then you must report if the reading is showing in OHMS, K OHMS, or M OHMS.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

Just check the resistance between the two legs of that resistor, TV not plugged into the outlet, meter set to 200 Ohms range if it has manual setting.
If it is in auto range then you must report if the reading is showing in OHMS, K OHMS, or M OHMS.

It's a manual DMM (Wavetek) The resistor RP806 is not giving any reading in ohms and when checking in Diode mode (for continuity) it does not beep (should it?) I have attached some photos to make sure I am checking the right resistor as you have mentioned a fuse which I cannot see.

Requested Photo of the circuit from the top attached.

PS: Yesterday when I saw that spark a component NT811S (photo) got damaged but it does not seem to be affecting as the voltage in the main capacitor is still 311VDC.

[budm]

Re: Samsung - no standby - already replaced all caps but still

It's a manual DMM (Wavetek) The resistor RP806 is not giving any reading in ohms and when checking in Diode mode (for continuity) it does not beep (should it?) I have attached some photos to make sure I am checking the right resistor as you have mentioned a fuse which I cannot see.

Requested Photo of the circuit from the top attached.

PS: Yesterday when I saw that spark a component NT811S (photo) got damaged but it does not seem to be affecting as the voltage in the main capacitor is still 311VDC.

So the fusible resistor RB806 10 OHMS 2W has blown open circuit probably due to shorted out STBY SMPS ICB801S.
The current limiter Thermistor NT811S 5 OHMS is also damaged.
So you have quite a bit of parts that will need to be replaced to get the stndby power supply section working first then we will find out if the PFC Bootser and the rest of the SMPS are OK or not.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

So the fusible resistor RB806 10 OHMS 2W has blown open circuit probably due to shorted out STBY SMPS ICB801S.
The current limiter Thermistor NT811S 5 OHMS is also damaged.
So you have quite a bit of parts that will need to be replaced to get the stndby power supply section working first then we will find out if the PFC Bootser and the rest of the SMPS are OK or not.

So it seems that it might be getting unfeasible to fix or aren't these components that expensive? Shall I replace the resistor RB806 and see if it blows again before replacing ICB801S? Is there a way I can test this before buying a new one?

PS: I have noted that your schematic is of bn44-00208A... mine is 208B (not A) - or they are interchangeable?

Thanks

[CapLeaker]

Re: Samsung - no standby - already replaced all caps but still

So it seems that it might be getting unfeasible to fix or aren't these components that expensive? Shall I replace the resistor RB806 and see if it blows again before replacing ICB801S? Is there a way I can test this before buying a new one?

PS: I have noted that your schematic is of bn44-00208A... mine is 208B (not A) - or they are interchangeable?

Thanks

Well that is up to you, if you think you can handle it, then go for it. If you don't want to fool around and just get it going, then order a new PSU. It's also a worth of time / money question. It's not a problem for Budm to get that board ticking I am sure, he is really good.

[budm]

Re: Samsung - no standby - already replaced all caps but still

Board REV A and REV B are interchangeable but the circuit diagrams are not exact matched.
Yo can check the resistance between the negative leg of the main filter cap and the leg of the resistor that goes to feed the Voltage to the IC to see if it shows low resistance reading, as you can see from the pictures from shopjimmy, 'A' version of the board uses the fusible resistor and the 'B' version uses the red rectangular fuse Time Delayed 2A fuse, the confusing part is that you also have 00208B but it uses fusible resistor, so there are 3 version of these 208x board. You can solder in Slo-blo 2A fuse 250V for testing. You will still need the new NTC also.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

Thanks. I WANT to go forward with the repair... but in the meantime my daughter is without a TV

Unfortunately I can't find the ICB801S locally and must be ordered which will take more time plus we might find other parts that need replacing. What I am afraid of whether there might be also damage to the Main Board or I can rest assured that the problem lies only within the PSU?

Also would you know whether PSU BN44-00213A is compatible with mine as a replacement?

Thanks

[budm]

Re: Samsung - no standby - already replaced all caps but still

Thanks. I WANT to go forward with the repair... but in the meantime my daughter is without a TV

Unfortunately I can't find the ICB801S locally and must be ordered which will take more time plus we might find other parts that need replacing. What I am afraid of whether there might be also damage to the Main Board or I can rest assured that the problem lies only within the PSU?

Also would you know whether PSU BN44-00213A is compatible with mine as a replacement?

Thanks

What is the P/N of the ICB801S as printed on the body/ We can get the spec sheet if the P/N does not match the diagram then we can check and see if it is shorted out or not.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

I have not removed it from the board yet. Will do and let you know. Thanks

[CapLeaker]

Re: Samsung - no standby - already replaced all caps but still

You need that PSU to work 100% first place, then you can check the other boards. Theoretically you could have more bad board(s) besides the PSU. We don't know until the PSU is fixed, then you try to turn the TV on and see what happens next.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

I understand.

[sciclunam]

Re: Samsung - no standby - already replaced all caps but still

What is the P/N of the ICB801S as printed on the body/ We can get the spec sheet if the P/N does not match the diagram then we can check and see if it is shorted out or not.

Its Q0365R. VJ36.