Toshiba 55g300u issue after issue

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

Okay cool. At the moment I do not have access to the TV since its at the shop. But first thing tomorrow I will get that info to you. Thank you so much for all the help.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

First thing in the morning I will get that info to you. Once again thank you so much for all the help. I will be sure to be careful. Sorry for the double post.

[budm]

Re: Toshiba 55g300u issue after issue

If you do have the Boosted Voltage, then the next thing will be checking for the 24Vdc at the connectors that go to the inverter boards.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

Ah okay it may have been there where I picked up the jump to 8 volts then the drop out. When the power button was pressed. I realize now that the noise from the transformer is typical and I feel a little dumb for pulling it out.

[CapLeaker]

Re: Toshiba 55g300u issue after issue

Ah okay it may have been there where I picked up the jump to 8 volts then the drop out. When the power button was pressed. I realize now that the noise from the transformer is typical and I feel a little dumb for pulling it out.

Transformers do fail, but not very often. What you should have done, is to unplug everything from the PSU and forced it on and checked the outputs, before ripping around in it.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

Transformers do fail, but not very often. What you should have done, is to unplug everything from the PSU and forced it on and checked the outputs, before ripping around in it.

Yeah I think I just wanted to open it up. Curiosity got the best of me on that.


I have 360V at the caps and I have 23-25 volts at the inverter boards.


EDIT: I just retested and I don't have 24 volts at the inverter board now.

[budm]

Re: Toshiba 55g300u issue after issue

OK, let me get this straight, the 24VDC is present on the power supply board connectors when both inverter boards NOT connected to the power supply board, but the 24VDC AND the 360VDC no longer present when BOTH Inverter boards are connected?

[Terryfictv]

Re: Toshiba 55g300u issue after issue

If you are making progress , you might want to replace the inverter boards and jumpers....
I have a new set-complete for sale.Let me know and I will research the cost and lower that price for you. eBay right now has a couple sets reasonably priced.....

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

OK, let me get this straight, the 24VDC is present on the power supply board connectors when both inverter boards NOT connected to the power supply board, but the 24VDC AND the 360VDC no longer present when BOTH Inverter boards are connected?

That is correct I just double checked it.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

If you are making progress , you might want to replace the inverter boards and jumpers....
I have a new set-complete for sale.Let me know and I will research the cost and lower that price for you. eBay right now has a couple sets reasonably priced.....

Okay cool. I may end up doing that. Or I may just drop it off at a local repair shop as a donation.

[budm]

Re: Toshiba 55g300u issue after issue

OK, the inverter has shorted out some where so it caused the power supply to go into protection mode due to too much current draw.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

Okay. So I should go through the inverter boards testing everything? Or just toss it?

[budm]

Re: Toshiba 55g300u issue after issue

You can try to locate shorted components such as the 3-pin Power MOSFETs first, or if the boards are cheap enough then get the new boards.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

You can try to locate shorted components such as the 3-pin Power MOSFETs first, or if the boards are cheap enough then get the new boards.

Okay what's the best way to test the MOSFETs? I don't have a whole lot of experience with them other than using lm7805s in small projects. Which I don't even know if that is considered a MOSFET.

[budm]

Re: Toshiba 55g300u issue after issue

Those big 3 pin device with big tab on top, so you look at it with big tab up: The left pin is pin 1 (GATE), middle pin (big tab) is 2 (DRAIN), and the right pin is 3 (SOURCE).
You will take the resistance reading of all 3 pin combinations and look for the reading with <50 Ohms.
1 & 2 = xxxx Ohms
1 & 3 = xxxx Ohms
2 & 3 = xxxx Ohms
The one that fails will more likely to show very low resistance between pin 2 and 3.

[x9x9x9x9x9]

Re: Toshiba 55g300u issue after issue

Seriously Budm you are amazing at this. Thank you. If I can't find the failed one(s) then I will just buy new boards. Thanks again.I'll let you know what I find.

[budm]

Re: Toshiba 55g300u issue after issue

Hands on, that is how you learn and you will never forget it when you find the problem and feel good about it.

[CapLeaker]

Re: Toshiba 55g300u issue after issue

hands on, that is how you learn and you will never forget it when you find the problem and feel good about it.

x 2

[CapLeaker]

Re: Toshiba 55g300u issue after issue

Seriously Budm you are amazing at this. Thank you. If I can't find the failed one(s) then I will just buy new boards. Thanks again.I'll let you know what I find.

A dead short like that should be easy to find... just follow B+ voltage as it is shorted to GND.