No power bn44-00440b

[JAMMASTER110489]

LN40D503F6F with no standby voltage(or light). No standby voltage on pin 13 (disconnected nor connected). Found the BN44-00440A schematics however some of the part have changed on the board. (ex connector CN802 on 00440A is an 18 pin and the 00440B is a 14 pin). Scats would be helpful and thanks.

[tvtimmy]

Re: No power bn44-00440b

Shopjimmy.com has a repair kit for under $20.
For the schematic try electrotanya.

[budm]

Re: No power bn44-00440b

LN40D503F6F with no standby voltage(or light). No standby voltage on pin 13 (disconnected nor connected). Found the BN44-00440A schematics however some of the part have changed on the board. (ex connector CN802 on 00440A is an 18 pin and the 00440B is a 14 pin). Scats would be helpful and thanks.

Are you sure the schematic you have is for BN44-00440A?
Upload the diagram for us to see.
Pin 13 is NOT standby Voltage pin, it is Swithced 5V (B5V).
The standby 5V pin is A5V (Always 5V).
I f you got that -0440A from here: http://www.electronica-pt.com/esquem...artdown/23435/
It is not the for BN44-0440A.
I f you look at the Title block you will see 'I40F1_ADY' which is the diagram for BN44-00340B which you can download from here from TOM66 site:
http://www.toms-service-manuals.com/...&typekey=0&p=5

[JAMMASTER110489]

Re: No power bn44-00440b

Are you sure the schematic you have is for BN44-00440A? No
Pin 13 is NOT standby Voltage pin, it is Swithced 5V (B5V).

The standby 5V pin is A5V (Always 5V).

It is not the for BN44-0440A.I need schematic for BN44-0440B

I f you look at the Title block you will see 'I40F1_ADY' which is the diagram for BN44-00340BYou are correct. So where can I get the BN44-00440A but preferably the B schematics?

Thanks,
Jay

[JAMMASTER110489]

Re: No power bn44-00440b

On my BN44-00440B, I have 0v on my A5v pin at connector. Seem like AC side is good.

[budm]

Re: No power bn44-00440b

So fuse FS802S is good?
What DCV do you have between the two legs of the main filter caps CP802, 803?

[JAMMASTER110489]

Re: No power bn44-00440b

Both fuses good and 165VDC. If I am remembering correctly. All caps look good and no scats usually makes it harder to find the problem. Are there no schematics.

[budm]

Re: No power bn44-00440b

OK, so you do have 160VDC on the main filter cap, the next thing will be troubleshooting the STBY Power supply section next.
I will have to look at the board layout to give you the test points for you to test.

[budm]

Re: No power bn44-00440b

You need to check the resistance between point A and point B, point C and point D.
Check the capacitance and the ESR of the two startup/running caps.
Check the snubber diode.
Get the P/N of the STBY SMPS IC.
Pictures provided by shopjimmy.

[JAMMASTER110489]

Re: No power bn44-00440b

Do I need to lift a lead or are these static in place checks?

[budm]

Re: No power bn44-00440b

No need to lift any parts' leads yet, just the resistance check between the two points to verify if the diodes have low resistance reading between the legs.
If it shows low resistance in both directions then it will have to be removed and retest. We just want to know if those two rectifier diodes are bad or not.

[JAMMASTER110489]

Re: No power bn44-00440b

A-B: 135 ohms both directions
C-D: 1.5 Mohm reverse 2 Mohm
Both starting caps: 5 ohms
snubber diode: 46.8 kohms
P/N of the STBY SMPS IC: looks like D8230DS or DB230DS but I couldn't find online as it was difficult to read.

[JAMMASTER110489]

Re: No power bn44-00440b

What should these be in circuit?

[budm]

Re: No power bn44-00440b

"A-B: 135 ohms both directions"
This reading for the rectifier diode DM806 is not right, you need to remove it and test it off the board.

[joefon]

Re: No power bn44-00440b

So what did you find? Did you find the right Scat? I wish people would close out a post thread with "hey this is what I found and it fixed it" He will never see this I bet.

[Farmboy]

Re: No power bn44-00440b

Okay, I don't know the date and time of the previous thread, but I have a different problem.

I have no backlights or images by flashlight to my screen. But I have received a repair kit of most likely components of bn44-00440b from Shop Jimmy. I have a friend, who can check ESRs' of my Caps if needed.

I will continue responses, as I digest the images. I do know that I have 80 dcVolts on the large capacitors, but I need to do more testing of the backlight lead pins.

I just wanted to introduce myself, mainly. I am a retired farmer, farm consultant, and USDA employee. I am back in the Midwest after retirement. I have studied agriculture, worked on the west coast, east coast, and farmed in Illinois. Have a good evening.

[neilc6]

Re: No power bn44-00440b

Couple of caps to check on the power supply board CP811 and CI1826.

https://www.badcaps.net/forum/showthread.php?t=58746

[Farmboy]

Re: No power bn44-00440b

I haven't forgotten about the TV repair and kit. I have been repairing the house.

[budm]

Re: No power bn44-00440b

"I do know that I have 80 dc Volts on the large capacitors," Is it the main filter cap in the hot side? If it is then it has to be measurement error or something, you need to recheck that.