Partially Blown Fuse?

[QQVO6/40]

Greetings all.

Down here in the Antipodes if you go to an electrical or electronic supply place you will be given a glass 3AG fuse with a tinned wire fusible element. Generally good.
On the other hand if you go to an automotive supply business you will, most likely, be given an el-cheapo 3AG glass fuse with a flat aluminium fusible element.
These things are horrid!
I mean, what could possibly go wrong?

Aluminium element, pressed and glued end caps made of nickel or tin plated steel.

Just add a little humidity and voila, vexatious headache.

Over the years I have had numerous problems with them. Especially if there has been any dampness near them.
I have had some display semiconductor capabilities. Some of which are temperature dependent, humidity dependent,the odd rare one that is voltage dependent, vibration sensitive.
You name it and it has been there.
I have lost count of the number of bits of radio stuff that has been repaired simply by replacing a garbage fuse with a real wire element fuse.

Went through a period where two way radios were dying at an annoying rate. Power on, lights would light and radio would receive ok.. Push the transmit PTT and dead.
Magic fix, new real fuse and away we go again back on the road.
Many years ago I adopted the practice of discarding any aluminium fuses I cane across.
No test. No mucking about. Just straight in the bin.

Beware the humble glass fuse. They might be small but can hide some really pesky gremlins.

Just my 2d worth.
Cheers all.
Robert.

[FrankB]

In my experience I have had literally shorted fuses, intermittent ones, and ones that test just fine on a meter, but open under load.

I had one that would open, and as it cooled, work for a while until the element heated enough to part again. That one was a nightmare to find.

Of course the intermittent clip type fuse holders in autos caused many fuse failures from heat/solder failure, not the fuse opening under overload.

[high_vacuum_house]

Good afternoon,
I have just had a fuse fail in a peculiar way earlier. This was the standard 20mm 200mA battery supply fuse in a Blackstar multimeter. I knocked it off the bench onto the carpet via my slippers (!) thus the multimeter only received a small bash.

The multimeter then failed to work. The fault found with another multimeter was an open circuit fuse on the PCB. The small shock had somehow broken the fuse wire in the fuse. A replacement fuse got it working again.