Samsung LN32B350F1 no video

[brianr20v]

Re: Samsung LN32B350F1 no video

That could explain why it comes in some times and doesn't at times.

[brianr20v]

Re: Samsung LN32B350F1 no video

The 312V is very marginal for the inverter circuit to work properly. Do you have capacitor meter to check the capacitance of that large cap since if the PFC not working, I expect the voltage on the cap to be at 230V (your country line voltage) x 1.414 = 325V but with very poor regulation due to failed PFC.

don't have that a meter that could read that large of a cap at this time but will be getting one soon ordered an ESR meter.

[brianr20v]

Re: Samsung LN32B350F1 no video

and my line voltage is 119vac.

[tom66]

Re: Samsung LN32B350F1 no video

I know that I've had a similar problem before with failed PFC circuit causing intermittent operation. TV'd work in my room with 245VAC nominal, but it'd fail in a friend's house that was getting 235VAC.

[budm]

Re: Samsung LN32B350F1 no video

If your line voltage is at about 120V (I did not know that Trinidad uses 120V in staed of 230V), then the voltage on the cap when it is in standby mode should be about 160V. Something does not make sense here.

[brianr20v]

Re: Samsung LN32B350F1 no video

yes we use both 120v and 230V but most aplinences run at 120v and yes the stanby voltage is around 160V

[budm]

Re: Samsung LN32B350F1 no video

That means the PFC must be running (since you are getting about 320V) which still does not make sense since the PFC IC is not getting enough b+ at the VCC pin to run either.

[brianr20v]

Re: Samsung LN32B350F1 no video

Well am just as confuse as u

[tom66]

Re: Samsung LN32B350F1 no video

There is a chance the PFC diode is bad, which will cause the output to sit at the input voltage. Have you checked all diodes on the HOT/Primary side for shorts?

[brianr20v]

Re: Samsung LN32B350F1 no video

yes i did but all was good

[budm]

Re: Samsung LN32B350F1 no video

Your TV inverter board has about the same design as the one I fixed the bad T-CON board. You can see that the voltage on the cap is about 380V.
http://s807.photobucket.com/user/bud...01561477778744

[brianr20v]

Re: Samsung LN32B350F1 no video

Let me ask u something DP805 what is the replacement for that diode because i was getting .43 on the meter can i replace it with one with the same value as DP810 and DP804 which is IN5408?

[budm]

Re: Samsung LN32B350F1 no video

Check the DP805 out off the board using Ohm mode to see if it shows resistance reading in both direction.

[brianr20v]

Re: Samsung LN32B350F1 no video

no its not i pulled all the diodes on the board and and tested all reads fine

[budm]

Re: Samsung LN32B350F1 no video

OK, I searched my archives, this is what I found.

[brianr20v]

Re: Samsung LN32B350F1 no video

31GF6 is the same number i have on my diode which reads .43 on the meter what u think replace it ?

[tom66]

Re: Samsung LN32B350F1 no video

The 450V cap could be bad, too.

[brianr20v]

Re: Samsung LN32B350F1 no video

Got a capacitance meter to read the big cap so will do that this afternoon and keep u all posted.

[brianr20v]

Re: Samsung LN32B350F1 no video

ok so the big cap CP815 reads good

[brianr20v]

Re: Samsung LN32B350F1 no video

Ok update i ordered the replacenment BOOSt Diode (31GF6) hope fully i should get it by the 15th of this month will keep u all posted.