BN44-00301A No signs of life

[snoptel]

Re: BN44-00301A No signs of life

Does that voltage drop when you unplug the board? It might be just left over charge from when it was working.
Or just check if you have any voltages on CN801, you should have 5.1V and 13V

Not sure if I'm completely out to lunch here..
I measured the IC. Roughly 320 VDC where marked and nothing on the other pins. I referenced the negative from the 320 VDC when checking the other pins.

Ohh, and upon closer inspection, looks like the blue ceramic cap was replaced at some point.

[snoptel]

Re: BN44-00301A No signs of life

no, the electrolytic with the rtv silicone stuck to it
next to jumper JP811

Thanks for the help.

[R_J]

Re: BN44-00301A No signs of life

Not sure if I'm completely out to lunch here..
I measured the IC. Roughly 320 VDC where marked and nothing on the other pins. I referenced the negative from the 320 VDC when checking the other pins.

Ohh, and upon closer inspection, looks like the blue ceramic cap was replaced at some point.

Like I said for the PFC CIRCUIT to work the STANDBY circuit MUST ALSO be working. as it supplies the VCC voltage to the pfc circuit ic.

There is a zener diode marked ZDM802, Check the voltage ACROSS this diode. This is one of the standby vcc voltages.

[snoptel]

Re: BN44-00301A No signs of life

Like I said for the PFC CIRCUIT to work the STANDBY circuit MUST ALSO be working. as it supplies the VCC voltage to the pfc circuit ic.

Sure, gotcha. not sure what the issue is then..

[R_J]

Re: BN44-00301A No signs of life

Sure, gotcha. not sure what the issue is then..

There is a zener diode marked ZDM802, Check the voltage ACROSS this diode. This is one of the standby vcc voltages.

[snoptel]

Re: BN44-00301A No signs of life

There is a zener diode marked ZDM802, Check the voltage ACROSS this diode. This is one of the standby vcc voltages.

Nothing, roughly zero volts DC.

I measured both forward and reverse bias..

[R_J]

Re: BN44-00301A No signs of life

Nothing, roughly zero volts DC.

With the negative meter lead on ZDM802 (anode), check the voltage on DM803 Cathode (white line)

[snoptel]

Re: BN44-00301A No signs of life

Nothing. 0.001 VDC

[R_J]

Re: BN44-00301A No signs of life

Nothing. 0.001 VDC

That is the vcc voltage for the standby ic as well as the pfc circuit, so I can only suspect that the standby circuit is not working after all.

[snoptel]

Re: BN44-00301A No signs of life

Earlier I asked about testing the board out of the TV because I was wondering if there I a signal from the ON button that would tell the PSU to start doing its thing. Is there a jumper that has to be installed somewhere??

[snoptel]

Re: BN44-00301A No signs of life

I also wonder may CM801 isn’t working properly seeing as how there’s 320vdc and no output

[R_J]

Re: BN44-00301A No signs of life

Earlier I asked about testing the board out of the TV because I was wondering if there I a signal from the ON button that would tell the PSU to start doing its thing. Is there a jumper that has to be installed somewhere??

You would first have to have the 5.1 volt standby voltage to be able to turn on the other voltages.

[snoptel]

Re: BN44-00301A No signs of life

You would first have to have the 5.1 volt standby voltage to be able to turn on the other voltages.

Ah, ok

[R_J]

Re: BN44-00301A No signs of life

I also wonder may CM801 isn’t working properly seeing as how there’s 320vdc and no output

That's not how the ic operates, That is only the high voltage to the drain of the internal mosfet. The ic also needs to produce its own startup vcc for the ic to operate at all. once the the ic is switching (at 50~100khz) the transformer feedback winding supplies a run vcc voltage to maintain the vcc voltage.

What is the number on the ic so I can look up the datasheet?

[snoptel]

Re: BN44-00301A No signs of life

That's not how the ic operates, That is only the high voltage to the drain of the internal mosfet. The ic also needs to produce its own startup vcc for the ic to operate at all. once the the ic is switching (at 50~100khz) the transformer feedback winding supplies a run vcc voltage to maintain the vcc voltage.

What is the number on the ic so I can look up the datasheet?

Hmm, ok.

Do you have the schematic for this board?

CM801's number is 3BR1065JF

[R_J]

Re: BN44-00301A No signs of life

Hmm, ok.

Do you have the schematic for this board?

No I do not, but most smps are similar. This uses the same standby ic

[snoptel]

Re: BN44-00301A No signs of life

No I do not, but most smps are similar.

Thank you for sending this.

I'm looking at the datasheet for the IC you requested. Doesn't look similar. The one on the board only has 6 pins

[R_J]

Re: BN44-00301A No signs of life

Thank you for sending this.

I'm looking at the datasheet for the IC you requested. Doesn't look similar. The one on the board only has 6 pins

What datasheet are you using? the one I looked up has 6 pins

[snoptel]

Re: BN44-00301A No signs of life

What datasheet are you using? the one I looked up has 6 pins

Can you attach it please?

[snoptel]

Re: BN44-00301A No signs of life

Got it.
So on the VCC pin what should the voltage be?