Fuse substitution in a LCD TV

[Stonent]

I picked up a 19" 720p TV at a charity store for $10 (SuperSonic SC-1911) .  The lady said she didn't think it worked because someone tested it with "this" (she holds up a Linksys router power supply) and it didn't come on. 

I looked at the back of the TV and it said 12V 35W Max and the power supply for the Linksys router was 12V ad 350mA. I told her my main concern was I couldn't tell if there were scratches or cracks on the LCD.

She said I could return it for store credit if it didn't work.  I took it home and as luck would have it, I had not one but two 12V power supplies with the right polarity, right sized barrel connector, and just enough wattage rating.

It was DOA so I opened it and started testing voltages and got the the point where there was voltage on one side of a fuse and not the other.  I shorted it out with some alligator clips and it powered up.  The fuse was 250V 5A or 2.5A (I can't remember which) which seemed a bit high for a TV that draws up to 35W at 12V.  One spot that I thought was the black goo from the LCD being cracked ended up being some black marker on the screen and some vigorous rubbing with 95% IPA and some finger nail scratching got most of it off.

The fuse was a slow blow axial lead glass fuse and I was wondering what the harm would be in bodging in a 12V 5A or 12V 3A automotive fuse instead?  I have a small supply of automotive glass fuses.

Again, the TV itself runs off of 12V and the panel is LED lit, so there shouldn't be any high voltages inside to worry about, so I assume the high voltage rating was just for transient voltage suppression?   If anything I would assume the lower voltage fuse would just be more likely to pop and I would assume not any less safe since it wasn't an HRC type.

I haven't been able to find any repair manuals on the TV, but when I searched for the part number of the main board I found a dozen or so identical TVs under various brands, some well known like Westinghouse, but others were equally as obscure as "SuperSonic"  The manuals all appeared identical except for the front and back pages that had the logos and contact numbers.

It appears to be a current product still as well http://104.171.7.220/index.php?route=product/product&path=67_68&product_id=83

What do you think?

[Richard Crowley]

The fuse was 250V 5A or 2.5A (I can't remember which) which seemed a bit high for a TV that draws up to 35W at 12V.

Well, 35W @ 12V = 2.9A according to Ohm's Law

Of course, you could actually MEASURE the power supply current.