Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

[rievax_60]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Important!
When did you measure the 15V at the other capacitor? With Dx805 in or out of circuit?

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Thanks rievax
With dx805 removed I believe did measure some pulsing output on the secondary standby line but less than half a volt (according to dmm).
So i guess next step is to replace the dx805 and then calculate the startup cell current before replacing the IC.

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

cm801 is at 15.35v with dx805 in circuit

[rievax_60]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

cm801 is at 15.35v with dx805 in circuit

That means to me that the circuit is working, check the secondary rails again.

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

You wouldn't believe it there now is 5.3v on the standby connector!

I wonder whether to try forcing it on or just try it in the tv

[rievax_60]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Try it in the TV. It is all confusing now. Working without a CRO and isolation transformer is like working blind.

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Indeed the TV appears to be fixed!
Picture looks great.
A lot of noise though from all the boards in the tv.
Must have been the startup cap and or the dx805.
That goo they had on the board was that important to replace?
Your help here has been amazing and learned much.
Best wishes for the new year everyone! this forum is a great place

[stj]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

goo?
if you mean glue, it's important to remove it all!

[nomoresonys]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

dam Rievax 60, you figured that out really fast, great job.

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

I wonder if it is worth upgrading the caps in the psu?
Seems to work great, ran it for about 1 hour, but I did notice that after about 10 mins running, it kinda reset, clicked off then back on again.
It is normal for plasmas to make alot of noise from the y and x sustain boards?
Would higher quality caps possibly quieten it down a little?

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Maybe I do have to replace some psu caps?
It started to go off and on.
And now it sometimes is failing to start up, can hear the relay clicking though.
Which still is much more than it was doing before.
Really, the caps in there are too small for such a load? The set is rated at 340 watt.
There is 1 small cap for the vs and a few other tiny ones for the other voltages.
Guess primary caps are just as important too?

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Anyone have any ideas which caps to try to replace first?
The Set works about half the time, sometimes takes a few attempts to start. the voltages all seem to be about right when it is running.
Definitely seems to click off more when a brighter picture is displayed. And it seems to be a little better once it has warmed up a little.
Have pulled a few caps and tested with multimeter and seem to be ok, but meter only reads to 100uf so cannot test them all.
Have tried reading up but some say that the newer Samsungs don't really have the capacitor problem? is this true, or should I replace them all? Thanks guys

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Hi Guys.
The VE Voltage on this TV seems to be generated by the XSUS board (the one on the right) from the VS supply (205V).

The Ve Voltage is reading about 143V. It is supposed to be 105V.

So about 40V too high. This would cause the shutdown cycle right? (overcurrent or protection)

The adjustment pot is on the XSUS board with a big VE next to the potentiometer. It is all the way down, cannot go any lower.

I think this is why is is power cycling, and making louder than normal noise when it is operating.

Tracing the Ve line into the XSUS board can only track it through a large 22 ohm resister to the middle leg of one transistor. Not to any caps or anything else. Ve must be filtered on the far left board where Ve is utilized.

Any ideas what could be causing the Ve voltage too high and not to be able to adjusted lower?

The transistor in question seems to test like a diode in two configurations. so presume it is not shorted.

btw guessing the smps is working properly now.

Any information really appreciated. Thanks

[rievax_60]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

I don't know anything about the VE rail. Does it measure high while the TV is displaying a picture or after it shuts down. Does the TV restart on it's own?
Maybe it's Erase Voltage?

[Badpowersupply]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Hi,
Ve Voltage is OK now.
Think the problem still lies in the psu.
Have taken it out of set and forced the pson and vson.
With no load, the power supply powers up, clicks on and all voltages are correct and stable.
Applying a load to the 15v or 5.3 v lines will cause it to power cycle, attempt to start as it does in the TV. click click click.
It will occasionally power the 21w 12v bulb fine. Also tested with 10w load (2 in series), same result.
Same behaviour as in the TV.
The current sense resistor for the low voltages transformer side reads up to 35mV with the 21w load and down to 3mV with no load.
I still want to replace this resistor as a test but cannot find a .39 ohm anywhere.
Could this be a bad current sense resistor or something else?

[rievax_60]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

It's going to be difficult to be certain of any cause. Try resoldering all of the large joints in the area, mainly transformer and secondary diodes. The IC is also suspect.

[budm]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

You have to be careful using lamp as the load, the cold resistance of the lamp will be 10~15 times less than the hot resistance which will cause very high in rush current that some power supply cannot handle and goes into shutdown/restart cycle.
Check the resistance of the lamps.

[Terryfictv]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Hello,
I have the same issues with the same power supply...
was there any further word on this thread / fix ?
I am worried about changing the power supply and not getting a solid, no recall fix! Is the X main the real culprit ? I do not have the set in shop yet....

[budm]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Hello,
I have the same issues with the same power supply...
was there any further word on this thread / fix ?
I am worried about changing the power supply and not getting a solid, no recall fix! Is the X main the real culprit ? I do not have the set in shop yet....

I think you should start a new thread since there was no follow-up on the problem, you should also upload good clear pictures (both top and bottom side of the board) of YOUR board for us to look at.

[Terryfictv]

Re: Samsung SMPS no standby question BN44-00514A (P60SW_CPN)

Understood. Thanks, I will wait to see if I pick up for repair.