Re: Toshiba 32AV502R
Well what gets me is there's a flowchart here ending in "5 volt supply on the power supply module", "power supply module", "main module", and "SYSCON circuit located on the Main module".
Now that last one sure could use some explanation... and it's the one I need, apparently. Well narrowing it down to the mainboard is very helpful, but WTF is the "SYSCON circuit"??? It wouldn't seem to be worth mentioning if it were unrepairable and simply required replacement of the mainboard...
Oznog
Member
Last Activity: 01-30-2025, 05:40 PM
Joined: 01-24-2013
Location: Austin
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Re: Toshiba 32AV502R
I found an APW7080 380KHz switching reg. It's got FB=0.8v which is what the datasheet says is normal operation, and the total Vout is 1.130v. The two divider resistors are labeled 622(6.2Kohm) high, 18C(15Kohm) low, which calcs to a target of 1.131v so that's correct.Last edited by Oznog; 01-24-2013, 09:34 PM.Leave a comment:
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Re: Toshiba 32AV502R
Found more regs!
On the other side of the control board are two labeled "1117", that's a reg #.
They're U19 and U20, both TO-263. U19 is labeled:
"APL117
WL43U"
And has "weird" voltages (below)
U20 is near that, labeled:
"1117
-50PE"
and is 5.00v. So, "good".
There IS another reg under the shield! SOT223 U26:
"APL1117
BL62M18"
And it measured 1.8v Vout. Well it's got "18" in the part...Last edited by Oznog; 01-24-2013, 08:54 PM.Leave a comment:
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Re: Toshiba 32AV502R
Well I wonder where we get 2.4v from here, the service info says the control board (mainboard) is what sources the 2.4v. I see the 3.3v and 1.8v linear regs.
2.4v is an uncommon voltage to actually use, the source is a mystery, and if you actually had 2.4v Vdd chips and a flaky reg passed 3.63v then you'll probably cause latchup and burn up the chip. Nothing's burned.
There MIGHT be another reg under the metal shield. I *barely* spotted the 1.8v reg under there....Leave a comment:
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Re: Toshiba 32AV502R
I see there's some "STA40T VTV-L4008" boards (same as mine) on eBay, but they mention being for 26", 37", or 40" AV502R TV's, and mine is a 32". Would it work or is the difference in screen size going to be a problem? Doesn't seem like it would be, the resolution and aspect ratio are the same, and the TCON board is what handles driving the LCD itself.Leave a comment:
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Re: Toshiba 32AV502R
I meant 0.063v. I just read 0.055v a few sec ago.
There is a 3.3v regulator on the mainboard. That part is working correctly.
Looking through the little vent holes in the silver shielding box on the mainboard, I spied a 1.8v regulator inside there! However, it's also working correctly, darn it.Last edited by Oznog; 01-24-2013, 03:38 AM.Leave a comment:
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Re: Toshiba 32AV502R
I went to the mainboard and tried chilling all the caps with freeze spray. Tried chilling the whole board. No change.
Tried heating the whole board with a hair dryer. No change.
Hmm, didn't note this before, probably doesn't matter- the green power LED lights once for under 1 sec when I plug it in. When I press the POWER button, it lights solid and stays lit- curiously, pressing the POWER button again won't turn it off.
I did find another Toshiba manual:
[URL="ftp://remote.bobbyjonesinc.com/TOSHIBA/MANUALS/LCDTV/COMPLETE.pdf"]ftp://remote.bobbyjonesinc.com/TOSHIBA/MANUALS/LCDTV/COMPLETE.pdf[/URL]...Last edited by Oznog; 01-24-2013, 03:14 AM.Leave a comment:
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Re: Toshiba 32AV502R
Can you see this album?
[URL="https://www.badcaps.net/forum/album.php?albumid=77"]https://www.badcaps.net/forum/album.php?albumid=77[/URL]Re: Toshiba 32AV502R
Can you see this album?
[URL="https://www.badcaps.net/forum/album.php?albumid=77"]https://www.badcaps.net/forum/album.php?albumid=77[/URL]Leave a comment:
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Re: Toshiba 32AV502R
OK I see here someone posted a mfg's service brief:
[url]https://www.badcaps.net/forum/showthread.php?t=23028[/url]
It says ACD shoud be 0.07v OUT of the supply board, and PWR is 2.4v INTO the supply board.
My first impression was that may be "close enough", but under more troubleshooting:
"Does a 2.4 volt on off signal appear at pin 13 of CN8 when the on/off button is pressed?"
NO-> "Is the Power Good (AC Detect) level less than .07V at pin 14 of CN8 when AC is applied?"
...Leave a comment:
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Toshiba 32AV502R
Just got a Toshiba 32AV502R. The prior owner said it "used to take a long time to turn on, then it stopped turning on."
The power LED turns on and stays solid-on after I plug it in and press the power button on the side panel or the remote. But nothing else happens. There's no backlight and it doesn't look like the LCD is displaying underneath.
Jumped right in. The 24v, 12v, and 5v supplies are good and stable.
INV is 0.010VDC (apparently the mainboard doesn't want to turn on the backlight yet)
DIM in 0.064VDC.
PWR is 3.63VDC....
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