USB not working

[ageman]

Hi Guys

does anybody have a service manual or schematic diagram for a samsung HG40EA670 TV.

The USB port isn't working and I am trying to identify some surface mount components.

Cheers all
Adrian

[dick_barton]

Re: USB not working

Have you got +5V supply at the USB pinout

[ageman]

Re: USB not working

Hi dick_barton.
Thanks for your question, no I do not have 5 volts. There is a surface mount device see attachment, this is where the 5 volt comes from. It is marked BS5, but cannot find this online, this was the reason for a schematic diagram.

Any ideas what this chip is?

Thanks
Adrian

[budm]

Re: USB not working

Please provide straight shot pictures that show more area of the board around the USB port and the whole top side of the board

[ageman]

Re: USB not working

Hi budm

have attached photos

thanks
Adrian

[budm]

Re: USB not working

1) What DC V do you get on both ends of C1501, 1505 with ref to GND?
2) What DC V do you get on both ends of L1501 with ref to GND?
3) What DC V do you get on both pin 2 of IC1501 with ref to GND?

[ageman]

Re: USB not working

Hi budm

1) -1.5 volts and dropping C1501 and C1505 joined together at top.

C1501 bottom 5.2 volts
C1505 bottom 0.0 volts

2)L1501 0.005 volts both sides.

3) IC1501 pin 2 to ground Middle pin bottom to ground 3.3 volts

Thanks
Adrian

[budm]

Re: USB not working

Hi budm

1) -1.5 volts and dropping C1501 and C1505 joined together at top.

C1501 bottom 5.2 volts
C1505 bottom 0.0 volts

2)L1501 0.005 volts both sides.

3) IC1501 pin 2 to ground Middle pin bottom to ground 3.3 volts

Thanks
Adrian

OK, so it looks like pin 4 of IC1501 is the 5V input. Pin 5 of the IC1501 looks to be the output pin which then goes to the USB VCC pin via L1501. Pin 2 of the IC1501 looks to be the control pin to turn on IC1501, so far I cannot find any info on this IC1501. I look at some Samsung main board schematic to see if some of them may use the same IC then we can figure out the circuit. That Pin 2 may be Active LO, <1V = ON.

[ageman]

Re: USB not working

OK budm

Thank you
Adrian

[budm]

Re: USB not working

BTW, can you check the resistance between either end of inductor L1501 and GND?
Also if you plug in USB device, do you get any Voltage on L1501?

[ageman]

Re: USB not working

Both sides of the inductor goes up to 396 Kohms assume there must be a capacitor charging.

No voltage if I plug in a usb stick on L1501

Cheers
Adrian

[budm]

Re: USB not working

OK, I found the info after lots of searching:
https://monitor.net.ru/forum/threads/558779/
IC1501 is RT8016L 1.5MHz, 600mA, High Efficiency PWM Step-Down DC/DC
Converter
https://cdn.badcaps-static.com/pdfs/...f042df7b46.pdf

[budwich]

Re: USB not working

great find.... I had opened up tablet with an issue with the USB. Similar chip "type" and couldn't find anything and ultimately replaced the main board. The problem I see is that people plug various usb things into the connector without realizing / knowing what power consumption the item has. It appears from the spec, that it is very limited and I bet there isn't any circuit design protection on the card and thus this component fails and is hard to find because of markings and otherwise. Again, great find.

[dick_barton]

Re: USB not working

Excellent find Budm

[ageman]

Re: USB not working

Thanks Guys for your help.Will replace, and let you know if successful. Got to wait up to 30 days for delivery of said item

Cheers
Adrian

[dick_barton]

Re: USB not working

I would check all the voltages at the pins1 to 8 of the IC especially the Enable input (Pin 2) which should be a minimum of 1.5V to enable the IC to switch on.
I think it's worth checking all while waiting for the replacement.