Sceptre 409BV-FHDU8HJ1L02 dead

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Alright - the BLon when the tv is off is 2 mV, when I turn it on, the voltage is 3.39v

The Adj voltage, when the screen is off, is 3 mV, when I turned it on, it jumped to 4.57V, but then dropped and stayed at 1.27V.

[budm]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Are you still getting only about 160VDC on the main cap? If you do, then the PFC Voltage booster is not working.

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

The main cap registered 160V off, 391V on

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Does that still imply the PFC Voltage booster is not working?

[budm]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

The main cap registered 160V off, 391V on

PFC Voltage booster is working.

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Well that's good news then.

Alright, where else should I look to figure this out?

[CapLeaker]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Measure between pins VBL+ and VBL- on the connector where the LED backlights are connected. You may need to use the Min/Max feature on the DMM if you have this.
I am thinking you got a bad LED in the backlights.

[budm]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Can we see the whole back side of the TV showing ALL the boards?
I believe the inverter board for the CCFL is INSIDE the panel.

[CapLeaker]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Oh! There I go... I had for some reason the impression that this was a LED TV!

Probably bad secondary on one of the inverter transformers.

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Here is a picture of the whole back. The individual boards can be seen in one of the first posts, but if you'd like, I can take additional ones.

Between VBL +/-, there is 0V registered with me turning it on and off.

[CapLeaker]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Well... you have to get at that inverter board on the left.

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

So for this inverter transformer, is that something I can get to and successfully fix?

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Ah ok. working on it now, pics to come

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

Here is that board on the inside

[CapLeaker]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

You can compare the secondary's on each transformer that they are within 3%. DMM in ohm setting.

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

I am not sure how to test for this. There are 4 connections on those transformers, which ones are the secondary?

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

It seems pins 1 and 3 are connected, but I can't find what 2 and 4 connect to.

[vinceroger69]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

is there any numbers on the transformers we maybe able to get a pinout etc

[bigmatt0211]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

There are some numbers/letters:
t51.8292.291
b2f 1235
00 4 C A 5

[CapLeaker]

Re: Sceptre 409BV-FHDU8HJ1L02 dead

a new inverter board is $14. You gonna need one anyway if one of these transformers is bad.