Fuse making noise when it blows?

[Naysayer]

I'm still a bit shaken.
I was adjusting the secondary to get 2kv (carefully) from doubler board when a loud Bang sounded. A cracking noise like an accidental arc. I was a few feet away and stunned. No smoke, no debris, all my caps are intact as are the 2 glass safety resistors on diode stack. No smell either. I run a low value fuse when testing and just raised it from 3 to 4A a few days ago. Standard 1" glass panel mounted. It was blasted inside glass not a simple break like I usually see after an oops moment. I don't see any scorch marks and the HVPS was energized for at least 2 minutes before it went. I guess I should lift the doubler PCB to check underneath, backtrack a little. I'm so close to applying RF I'm getting impatient.

Anyone experience a noisy fuse ?
neil, NYC

 

[Holydvr]

I have not overall. Maybe a subtle pop, but not as you describe. There are many here more qualified to speak, but I would backtrack after discharging any caps that need it done.

 

[Captain Kilowatt]

Where in the circuit was the fuse located? Was it in the high voltage line? Regular glass fuses should not be used in high voltage applications because they will sustain an arc if the fuse opens. Sometimes that arc can be rather surprising and yes it can indeed go bang sometimes. High voltage fuses contain a type of sand so that any arc is suppressed immediately.

 

[Naysayer]

Where in the circuit was the fuse located? Was it in the high voltage line? Regular glass fuses should not be used in high voltage applications because they will sustain an arc if the fuse opens. Sometimes that arc can be rather surprising and yes it can indeed go bang sometimes. High voltage fuses contain a type of sand so that any arc is suppressed immediately.

I lowered the AC voltage to 920 -it was 1100- by moving the buck-boost wires (AL572 transformer).

The fuse is right after the AC inlet, before everything including soft-start module. I removed the HVPS board (V doubler) this morning and found no scorch marks at all, no smells. All looked OK. Screen (400v) circuit OK too. Everything else is low voltage. Another mystery I guess. Noise frightened me, loud.

Got the opto-coupler sockets in today's mail so hopefully I can apply RF soon.

 

[sp5it]

It was arc inside tube.
Mike

 

[Naysayer]

Have not yet put tubes in. I need to start a new thread as I'm adjusting the Plate supply now. Thank you.
neil, NYC

 

[Onelasttime]

Don't feel bad. Some guys on this site are super smart and experienced with high voltage tube gear some even commercially so. That is not me. I am a very careful, cautious and learning every day!

When I was a young pilot I had a fuel tank drain fail, bad weather roll in insanely fast on a clear summer day and a cockpit fire that took out 1/2 of my cockpit. I ended up landing the plane dead stick and did not see the actual runway until I was 20 feet above it! When I am working on high voltage tube amps I am more attentive than I was that day! Not fearful but focused, attentive and very deliberate! When a part breaks, pops and comes flying at you it scars the crap out of you!

The second you relax too much and take things for granted that is when it get's you! I have seen rf and high voltage do some strange things before. Many men smarter than me and better educated on electronics, electrical engineering and rf circuits have died.

On the other hand you have people like Nikola Tesla and Maxwell that flirted with deadly forces the way I taunt my wife and lived long lives!