Change line fuse on an Asante Maccon daughter card

[bobo68]

I need to change the fuse (12V, 0.5A) you can see on the pictures. Do I have to solder in a new one or can I change just the inner part of the fuse? It looks like the the whole thing consists of two end parts and an inner part but I cannot move the inner part. So maybe it is just one piece.

TIA, bobo68

 

[techknight]

thats a solder type through-hole. you will need to change the whole fuse, however I am more concerned on why it blew and if there is any other collateral damage. 

 

[uniserver]

plugging in  a macintosh monitor blows it.

 

[techknight]

ouch. that would be bad. and why would anyone do that? 

 

[uniserver]

aui and mac monitor use the same port.

 

[techknight]

oooohhh. So a blond moment then. 

 

[uniserver]

blonde yeah haha... or Whoops?   or crap....  or Why is this video card not working...?   LOL

 

[techknight]

Strangely enough, I never have done that before. Granted ive done some stupid things in my day, but that wasnt one of them. 

 

[bobo68]

That was the reason why Apple later introduced their proprietary AAUI port. AUI has the same port as the Apple monitors of that time.

The fuse does not look blown so I first ignored it and did a lot of fiddling with software and a switch to get the external AUI transceiver to work. I learned to things: 1) the switch on this card model has to be set to TK (thick ethernet) to use the AUI port and 2) better check a fuse even if it looks good. 

P.S. actually this card was sold on ebay as a video card - but the thin coax port looked suspicious. 

 

[uniserver]

so it looks like before you pay big money for a NIC card, for your se/30, make sure to look for SE/30 video cards on ebay first HA HA.

 

[bobo68]

Yep, payed 25 Euros for it - not bad I think. It's can get even more weird: if you want an SE/30 you should also look for an "Apple SE/30 monitor". That's the way one ebayer named his SE/30. Obviously he could not believe that there is a whole computer in it. Same with an Atari 520ST which was once titulated as a "Atari keyboard".

 

[macman142]

To me that looks like a fuse in a soldered-on fuse holder. But it appears you'd need to desolder at least one end of the fuse holder in order to release the fuse from between the two fuse holding end cap thingos.

 

[bobo68]

Yes, that can be the case. There seems to be a rim between the outer caps and the fuse itself. I'll fire up the soldering iron and have a look.

 

[techknight]

Its NOT the case. It is NOT a fuse holder. Pigtail fuses come manufactured like that.

 

[bobo68]

Of course you were right.

The fuse is a 230 2AG type, rated *250 V*, 0.5 A. Seems weird to me because it sits between the 12V feed from the Asante Maccon PDS card and pin 13 of the AUI connector (voltage plus). Would a fuse of these dimension even give protection in this case?

 

[techknight]

of course. 250V is the maximum safety range at which you can insure it wont arc-over at which the fuse becomes a spark-gap. 

it is also rated at 0.5Amps. or 500mA. if the current exceeds this regardless of voltage (could be 1V, doesnt matter). it will blow. 

 

[bobo68]

Ok, didn't know that not U*I but just I is important for the fuse to break the circuit. Had to replace it with a bigger type (20 mm x 5 mm) with holder caps though but now it works.

 

[techknight]

awesome

 

[CelGen]

You can always swap out the glass fuse with cheaper and more common fuses so long as the ratings match. Nobody will ever notice.