Don't judge a glass fuse by its looks!

[Sludgenutz]

I have come across non-functioning "dead" electronic gear many times. Normally, the specially calibrated wire within the fuse burns with obvious results. A visual inspection reveals a burnt center wire, and replacement of the fuse with the same type recommended by the manufacturer will suffice.

Not so fast, I say! I have seen a few glass fuses where the fusible wire has NOT burned up in the middle of the fuse....but rather at the junction where the metal end caps are attached to the glass tubing! They "look OK", but they will not function, as the portion of the fuse that failed first is not visible!

I will say this is a RARE occurance. However, keeping a spare fuse set handy, or multimeter may save a worthless/expensive trip to the repair shop.


Peace.

 

[wixedmords]

Re: Don't judge a glass fuse by its looks!

Here! Here! Sludge.

One may not be able to judge a bad fuse visually.

Good reminder.

 

[Artie]

Re: Don't judge a glass fuse by its looks!

Great advice. As one who's worked as an electronics tech for several decades, I can tell you that this happens more often than you might think. Its a failure mode that often happens due to physical shock rather than electrical overload. Like when you lift a heavy amp onto or off of a stack several times a month.

 

[Sludgenutz]

Re: Don't judge a glass fuse by its looks!

Thanks guys! Artie, now that you mention the "physical shock" issue, I can honestly say that none of the "dead" units I serviced with this funky fuse issue ever had deeper power supply problems!:fingersx: I just replaced the fuse, and it was good to go. Failures were recorded, so I would know if there were repeat issues, even years after repair.

 

[RushOfBlood]

Re: Don't judge a glass fuse by its looks!

I have seen this multiple times!