Samsung UN40EH5300F No Power

[Davi.p]

Re: Samsung UN40EH5300F No Power

Why resume so an old thread??!

[Ndoty22]

Re: Samsung UN40EH5300F No Power

You trust ebay?
The 3s111 chip goes for $13 on Amazon.(10). The board, if found is over $100

[budm]

Re: Samsung UN40EH5300F No Power

Thanks for the follow-up.

[meantomatoes]

Re: Samsung UN40EH5300F No Power

The transformer is clicking due to shorted diode so it goes into shutdow/re-start cycle.

happy to report that with the new diode all is well! TV works perfectly! thanks everyone for helping

[budm]

Re: Samsung UN40EH5300F No Power

The transformer is clicking due to shorted diode so it goes into shutdow/re-start cycle.

[meantomatoes]

Re: Samsung UN40EH5300F No Power

OK, P/N of the diode is SR306.
https://cdn.badcaps-static.com/pdfs/...5503693a68.pdf
It is recommend to use SBX0 series instead per datasheet.

https://www.digikey.com/product-deta...SCT-ND/3504331
The IC is more likely to be OK.

okay, ordered SB360, will keep everyone posted. what do you think of those other two diodes with fluctuating voltages? they have a different P/N unfortunately. they're on a different transformer leg than DM851C. and the transformer clicking?

[budm]

Re: Samsung UN40EH5300F No Power

OK, P/N of the diode is SR306.
https://cdn.badcaps-static.com/pdfs/...5503693a68.pdf
It is recommend to use SBX0 series instead per datasheet.


https://www.digikey.com/product-deta...SCT-ND/3504331
The IC is more likely to be OK.

[meantomatoes]

Re: Samsung UN40EH5300F No Power

OK, shorted out diode then.
I should have caught that when you indicated "DM851C has no resistance in either direction," in the earlier reply.

What is the diode P/N?

SR306 with 342Y under that. so it's likely the diode that's the problem and not that IC or transformer making the clicking sound?

[budm]

Re: Samsung UN40EH5300F No Power

shows 00.7 ohms in both directions. on diode mode, it shows 001 shorted together, and 1 not shorted

OK, shorted out diode then.
I should have caught that when you indicated "DM851C has no resistance in either direction," in the earlier reply.

What is the diode P/N?

[meantomatoes]

Re: Samsung UN40EH5300F No Power

Are you sure when using Ohm mode on this diode it did not show shorted in both directions?
What do you get when you short the meter probes together in diode mode, does it also show '001' or '000'?
What do you get if you do not short the meter probes together?

shows 00.7 ohms in both directions. on diode mode, it shows 001 shorted together, and 1 not shorted

[budm]

Re: Samsung UN40EH5300F No Power

Are you sure when using Ohm mode on this diode it did not show shorted in both directions?
What do you get when you short the meter probes together in diode mode, does it also show '001' or '000'?
What do you get if you do not short the meter probes together?

[meantomatoes]

Re: Samsung UN40EH5300F No Power

The DM851C your test result using diode mode does not make any sense, it should on show reading in one direction only when tested off the board , basically shows like diode with just lower Vf. Can we see the meter screen shot of the readings in both directions?

sorry for the bad quality

[budm]

Re: Samsung UN40EH5300F No Power

DM851C that i pulled from the cold side to test it. that shouldn't affect the IC should it? i'm not sure which pin is which, there's a little arrow on one of the pins, that one is showing 3V. the one to the left of it is showing 0 and the leftmost is 304V AC, except it drops and quickly regains with a new clicking noise at or near the transformer. is this because of the removed diode? the pin across from the leftmost and the adjacent one show 0. the next adjacent one actually jumps up to ~57V with the click and slowly falls down. the rightmost is 0.


yes, or a similar low reading. once it was showing 019 and then 009 and then 003 in both directions.


thanks. it's also a learning experience for me, i've already learned a lot about this stuff.

The DM851C your test result using diode mode does not make any sense, it should on show reading in one direction only when tested off the board , basically shows like diode with just lower Vf. Can we see the meter screen shot of the readings in both directions?

[meantomatoes]

Re: Samsung UN40EH5300F No Power

??? what diode??
There are a series of 3 resistors that go from the main cap positive to supply the ic with its vcc voltage, If its not there the ic won't operate.

DM851C that i pulled from the cold side to test it. that shouldn't affect the IC should it? i'm not sure which pin is which, there's a little arrow on one of the pins, that one is showing 3V. the one to the left of it is showing 0 and the leftmost is 304V AC, except it drops and quickly regains with a new clicking noise at or near the transformer. is this because of the removed diode? the pin across from the leftmost and the adjacent one show 0. the next adjacent one actually jumps up to ~57V with the click and slowly falls down. the rightmost is 0.

001 in both directions?

yes, or a similar low reading. once it was showing 019 and then 009 and then 003 in both directions.

Here's the ebay link, just in case.

thanks. it's also a learning experience for me, i've already learned a lot about this stuff.

[nomoresonys]

Re: Samsung UN40EH5300F No Power

Here's the ebay link, just in case. https://www.ebay.com/itm/SAMSUNG-UN4...bF9P1#viTabs_0

[budm]

Re: Samsung UN40EH5300F No Power

same reading

001 in both directions?

[R_J]

Re: Samsung UN40EH5300F No Power

should i put the diode back on before testing?

??? what diode??
There are a series of 3 resistors that go from the main cap positive to supply the ic with its vcc voltage, If its not there the ic won't operate.

[meantomatoes]

Re: Samsung UN40EH5300F No Power

The ic is similar to this SSC1S311, pin 1 is controlled by the opto to switch the ic out of standby condition. Check the voltage on pin 4 using the main cap's negative for meter ground
Sometimes one of those series resistors coming from the main cap's (+) goes open.

should i put the diode back on before testing?

That board is $25 on ebay shipped. Not sure why you don't just buy another one. I had scrapped some 50" Samsung LED TVs and found out after that the boards were selling for $10 to $20 on ebay with shipping.

seems wasteful to me

[neilc6]

Re: Samsung UN40EH5300F No Power

That board is $25 on ebay shipped. Not sure why you don't just buy another one. I had scrapped some 50" Samsung LED TVs and found out after that the boards were selling for $10 to $20 on ebay with shipping.

[R_J]

Re: Samsung UN40EH5300F No Power

The ic is similar to this SSC1S311, pin 1 is controlled by the opto to switch the ic out of standby condition. Check the voltage on pin 4 using the main cap's negative for meter ground
Sometimes one of those series resistors coming from the main cap's (+) goes open.