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Old 03-18-2009, 12:26 AM   #1
lkvee
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Default Sharp LC-20B2UA keeps blowing a fuse

I also wanted to be confident about the capacitors in this TV. Fuse F3701 rated at 2A and 125V would blow as soon as the TV is turned on. In the pictures, the fuse has been extracted.

I also see five Nichicon VZ(M) capacitors at 1000uF and 16V with the designations H0233 at 105 degrees C. I also remember seeing a KMG capacitor rated at 2200uF and 16V.

I thought I remember seeing other postings addressing the blown fuse, but I can't find them anymore.
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Old 03-18-2009, 09:41 AM   #2
Wizard
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Default Re: Sharp LC-20B2UA keeps blowing a fuse

What this fuse is for WHAT? That means tracing removed circuit board to see where this goes to from that popped fuse.

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Old 03-18-2009, 10:16 AM   #3
lkvee
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Default Re: Sharp LC-20B2UA keeps blowing a fuse

Not sure how URL's are parsed out, but I think I found a schematic. It's in (Spanish?) Portuguese, and going to the URL will initiate download of the schematic. I'm illiterate with regard to reading these, though.

http://www.electronica-pt.com/index....tdown/id,1476/
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Old 03-18-2009, 11:09 AM   #4
PlainBill
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Default Re: Sharp LC-20B2UA keeps blowing a fuse

Quote:
Originally Posted by lkvee
Not sure how URL's are parsed out, but I think I found a schematic. It's in (Spanish?) Portuguese, and going to the URL will initiate download of the schematic. I'm illiterate with regard to reading these, though.

http://www.electronica-pt.com/index....tdown/id,1476/
Thanks for the link. Reading schematics is almost as much fun as reading cmsix's stories on storiesonline.

That appears to be an unregulated supply to the B+ voltage regulator. Remarkably, this regulator does not seem to have current sensing!!! Am I missing something? Do you have the tools and expertise to troubleshoot this? A decent DVM is essential.

Possible components include C3710 and C3712, Q3702 and T3701. On the secondary side of T3701 I see D3704, D3705, D3706, D3708, C3714, C3716, C3718, C3721, and C3722.

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