Blowing fuses?
#1

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.
#3
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.
Taz
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.
Taz

#5
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.
Taz
I still miss the old tube days.
Taz
