Toshiba 50l1350u low power to LED

[dick_barton]

Re: Toshiba 50l1350u low power to LED

Yep, two boost converter circuits, you can see two inductors (LL1, LL2), two Power MOSFETs (driven by the OB3372), Two boost DiodeS DL2, DL4.
SMD MOSFET QL5, QL1 (PWM driven) are the return (Cathode) lines for the LED string returns (two set of LED strings).
If you can find the application notes circuit of the OB IC, then circuit will probably be close to what you have on your board. The OB IC may be damaged when the MOSFET went out.

The manual in post #9 has a similar led driver stage.

[budm]

Re: Toshiba 50l1350u low power to LED

P0920ATF data sheet

I just look at the service manual, thanks.

[Gundulf]

Re: Toshiba 50l1350u low power to LED

The manual in post #9 has a similar led driver stage.

i missed this post

[Gundulf]

Re: Toshiba 50l1350u low power to LED

Yep, two boost converter circuits, you can see two inductors (LL1, LL2), two Power MOSFETs (driven by the OB3372), Two boost DiodeS DL2, DL4.
SMD MOSFET QL5 (3?), QL1 (PWM driven) are the return (Cathode) lines for the LED string returns (two set of LED strings).
If you can find the application notes circuit of the OB IC, then circuit will probably be close to what you have on your board. The OB IC may be damaged when the MOSFET went out.

The mosfet is BAD So from here What to do? should i just get a replacement board or will it be worth it to try and replace the mosfet and the resistors and see if the IC is working? what would you guys do?

[dick_barton]

Re: Toshiba 50l1350u low power to LED

Check how much a replacement circuit board is with Shopjimmy and compare the price against the cost/availability of the components and how good your soldering skills are.

[dick_barton]

Re: Toshiba 50l1350u low power to LED

You could contact these people and see if the parts are suitable for your set.

http://www.tvtechparts.com/PK101W0-R...54_p_5215.html

[Gundulf]

Re: Toshiba 50l1350u low power to LED

Thanks for the link Dick, that will be the option to go if the Ic is damaged hope not haha. I found this
http://www.st.com/content/ccc/resour...CD00000701.pdf to replace the http://products.niko-sem.com/images/...8769732102.pdf

would it be fine with that mosfet?
thanks for the help!

[dick_barton]

Re: Toshiba 50l1350u low power to LED

The TO-220FP would probably be OK. It has the voltage, current ratings and same pinout and in an isolated package. I suggest you check the physical size against the P0920ATF.

[Gundulf]

Re: Toshiba 50l1350u low power to LED

Hello Guys

After a couple weeks of wait, and having enough time to sit and do it, finally i got the resistors and the mosfets and replaced them. Now i have no power
I went ahead and replaced both mosfets, even though one was okay. So i'm not sure if by removing the one good mosfet(asuming the ones i got are not good replacement) would cause me the no start.
i replaced the P0920ATF with IRF630.

Anyways i took the readings out of this plug

and i have:
0v on 15
5.17v on 14(has no cable)
0v on 13
4.40 v on 12
3.20v on 11
5.17v 10
and 0v on 9-1
what could the problem be now? lol I will later replace the good mosfet back into place and see if at least i recover what i had before(power on but no leds) Any ideas?