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Xmas Emergency! - tv power board IC question

MtnFrost

Dec 25, 2014
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Dec 25, 2014
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Help!

I was repairing a television (Toshiba 37XL96) power supply for a surprise TV present for my wife.

The parts dealer sent me the wrong IC - I needed a STRW6765. They sent a STRW6735.

Now looking at the stats, the difference is this:

the 65 - 800 V / 1.8 Ω, 52 to 110 W (Universal/230 Vac input)
the 35 - 500 V / 0.57 Ω, 160 W (120 Vac input)

Now I know enough electronics to make simple circuit board repairs. But this is a little beyond me. Could I use the -35 instead of the -65, since it's just a switch for the power relay?

I can't get another part Xmas eve, but if I can use this, please let me know asap! A Christmas gift is depending on it!

Thanks!
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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Jan 21, 2010
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25,510
What's your power supply voltage? If it's 120V or thereabouts I'd give it a go.

For a better answer you'd probably have to post the circuit diagram.

I'm assuming you're replacing a dead one. The worst that will happen will be that this one will die, probably blowing the main fuse in the process (If I understand what it is used for).

The main problem I see is that if it immediately fails, you won't know whether you've exceeded it's specs due to it being the wrong part or due to another failure somewhere else that would also have taken out the correct part.
 

MtnFrost

Dec 25, 2014
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Dec 25, 2014
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120 Volts. Yes, I'm replacing a bad IC. I replaced two of three ICs known to go bad, and had to reinstall the old IC when I realized they sent me the wrong part. Of course, the tv relay just clicks and the tv stays off with this bad IC back in there.

THANK YOU! I wouldn't care if it just blew out, as long as it didn't wind up frying the board in the process.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
Moderator
Jan 21, 2010
25,510
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25,510
THANK YOU! I wouldn't care if it just blew out, as long as it didn't wind up frying the board in the process.

I can't promise anything, but I would personally give it a go. If this TV has a wide input voltage range then it is likely the higher voltage part was chosen to allow operation at the upper end of the range.
 

MtnFrost

Dec 25, 2014
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Dec 25, 2014
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That's what I was thinking. And no worries, I won't hold you to anything. I'll let you know - putting it in now.
 

MtnFrost

Dec 25, 2014
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Dec 25, 2014
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Well, that was a wash. Looks like I may need to look elsewhere. The -35 didn't blow or anything, but the symptom of the relay clicking over without engaging the circuits remains. Maybe a bad cap, though all look good. Thanks for you help. Have to give it as a 'work in progress'.
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
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Nov 28, 2011
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Hi there. Are you still interested in getting this set going?

I didn't find service information for it, but from your description, I suspect this IC is a switching power supply, not a relay controller. In that case, when the original one failed, it probably took out a fuse or a fusible resistor. That would explain why the new one didn't fix the problem.

If you want to take this further, upload photos of both sides of the board in the relevant area.
 
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