Blowing fuses?

Old 10-26-02, 08:07 AM
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Angry Blowing fuses?

my zenith widescreen model # A50M84W1,has blown it's original fuse.Went and purchased some more @ Radio Shack(the attendant picked them out) and everyone blew as well after plugging the set back in,it is a 4A/250V 312.The new fuses don't have the 312 on them and look an 1/8 of an " shorter.Are they the wrong fuses or is something else wrong? Thanks for any help.
Old 10-27-02, 10:16 AM
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Just in case I didn't describe the t.v. itself it is a Zenith 50" projection I think?the kind that projects the image unto a mirror at the back then to the screen.
Old 10-27-02, 12:41 PM
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size is important, but blowing fuses is a bad sign

While fuses can go bad, and a properly sized fuse (both physically and amperage) is important, if you have a spring loaded fuse holder, the size of the fuse should be okay.

So long as the fuse is making good contact on either terminal, you can assume that the 1/8" difference is no matter. What it sounds like to me is that some of your capacitors are drying and the power supply is taking more surge current to start up. Try this, get fuses up to 3 amps more than the system calls for. So if you have 5 amps rated, get 6, 7 and 8 amp of the same type. Try the 6 first and so on. If all of these die on startup, you've got a larger problem.

If you're familiar with, and can operate, a multimeter with Amperage capability you can see what the surge current is. I'd recommend one that can handle around 20 amps, just in case the draw is too much, your circuit breaker can shut off the power.

If, however, your 6 amp fuse does the trick, check your line voltage and make sure it's between 110 and 125 volts. If it's at 110 and it used to be 125, this could explain the sudden onset of the problem.

Another alternative is Slo Blo fuses. You'd get the same amount rating on these, but they allow current to pass momentarily and don't blow unless the amperage is high for longer than a few seconds.

Hope this helps.

Old 10-27-02, 02:35 PM
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IN my experience

Caps rarely cause fuses to blow, normally it is the rectifier bridge or regulator shorted causing the problem.
But who knows you might get lucky..
Old 10-28-02, 05:07 AM
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true, but that's why...

Yes, you're right. If he gets a direct short, those are the likely villians, but if a larger fuse size gets the set functional, the caps are the most probable source. Depends on the power supply they used in that model. Some broadcast monitors use isolated supplies that caps that dry take the surge current just above fuse rating.

I still miss the old tube days.


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