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Replacing IEC C14 socket and/ or fuse

Started by Mr.Penfold, February 13, 2018, 10:19:57 PM

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Mr.Penfold

Hey! so I've been trying to figure this issue out for a while now and have gone to quite a few different electronic shops with no one able to help me with a solution, so thought I would ask a forum!

Basically I got given a bass amp head (Behringer BX300T), which was just missing the fuse out the back but apart from that apparently working fine and had never been opened up by the owner. The fuse holder looked like one I'd never seen, with 3 terminals and pushed close together (no space for a regular glass/ ceramic fuse).



I thought possibly it took a thin blade fuse like used in cars but I've never seen other devices use those types of fuses. Also thought possibly the pins have been pushed together in the past, but then I'm still not sure what the middle terminal would do unless it was some sort of 3 pin fuse? The middle fuse connecter was wired to the neutral of the power socket pin on the backside.



So I tried a regular fuse and it didn't fit, and was told it definitely wouldn't be a car type blade fuse. Wasn't sure if there was a holder tray that held it in place. Asked a guy in an electronics shop and he said he'd never seen one like it and it'd be easier just to replace the whole socket. The sockets they had have a regular two connector fuse holder. So I took the old socket out and found a different pin layout on the back of the two and got stuck as how to rewire it with the new socket.

This is the new socket back:


The wiring runs through to a switch and then to the unit.


With the original the live went from the socket, up through the switch, and then to the unit. And two other wires went through the fuse to the unit. The neutral to itself on the fuse? And the ground to the ground in the unit.

With the new socket, the live is forced to run through the fuse, so I assume that then runs up to the switch. Ground to the ground. But that leaves me stuck with the neutral and also the two wires coming from the unit that were running through the fuse previously.

It was hard to get in there and take clear photos so I've drawn it out as clearly as I can:


So basically need to either get this new socket wired in (as no one seems to recognise the original one), or get a fuse that fits the original (which no one seems to know what it is).

Let me know if this is confusingly written and I'll try to clarify, I am very novice to it all! Thanks for any help!!

Enzo

The fuse goes in the part you are missing.  It plugs into those contacts.  It is a rectangular black thing, and by flipping it upside down you select 120 or 240v operation.  Thus the two tap wires.

See the tiny triangle up by your index finger, molded in the plastic by the edge of the rectangle hole?  On the fuse bloc is a little 240 on one side and 120 on the other side, so whichever you line up to the arrow, is how the amp is configured.

You are not going to find just a replacement fuse block for the thing unless some shop has one sitting loose from a dead unit.  SO just replace the whole thing.

You won't need the voltage switching feature, so a regular socket like you seem to already have works.  Now determine whether the blue wire or red wire is 120v or 240v, wire up the one you need and tape off the other.

Mr.Penfold

Awesome thanks heaps!!

So just for my own understanding... the fuse in the missing part for the original, is almost a half length fuse? And effectively connects the neutral to the blue wire, or the neutral to the red wire depending on how it is flipped? (ie. only connects two pins at once, not all three?)

So once I figure out if blue or red is 240v (I'm in Australia), I wire that directly to the neutral, or do i run it through the switch also?

Any advice on finding out which is 240v?

Thanks again!

Jazz P Bass

What was in the amp is a Bulgin IEC connector.


Mr.Penfold

Cheers! would you recommend replacing it with another or just wire it straight for the 240v option like Enzo said?

Enzo

The clips you see in the hole are not the fuse clips, they contact the holding block that is missing.  The fuses are standard size 20mm.  The holder has only two contacts, one in the middle, and the other at one end, so the fuse connects to one or the other end contacts, completing the circuit to 120 or 240.

Many times I have had people bring things to my shop, and they have the fuse clip upside down, set for 240.  But on 120v, that makes the mains effectively only 60v.

You can buy a new switching holder just like the original one, or buy a single voltage one and wire it for 240.  Doesn;t matter which, do whatever is more convenient for you.

g1

Just make sure if you use a receptacle without a fuse in it, that you add a fuse in series with the hot lead.

phatt

Quote from: Mr.Penfold on February 14, 2018, 12:03:54 AM
Awesome thanks heaps!!

So just for my own understanding... the fuse in the missing part for the original, is almost a half length fuse? And effectively connects the neutral to the blue wire, or the neutral to the red wire depending on how it is flipped? (ie. only connects two pins at once, not all three?)

So once I figure out if blue or red is 240v (I'm in Australia), I wire that directly to the neutral, or do i run it through the switch also?

Any advice on finding out which is 240v?

Thanks again!

There might be a label on the side of the transformer, if so it will likely give the colour code of the red and blue, otherwise you will need a meter to find which one is 240VAC.
Yes wire it with the main switch.

If you will not be moving OS then buy the single mains with fuse.
Those dual voltage fuses are a trap for the novice. (They should be banned :grr)
I nearly got caught with one of those a while back, just lucky I noticed that little white arrow and realized before I powered up.
If you get it wrong it will most likely burn out the transformer as well as destroy the whole Amp.
So make darn sure you wire up the right wire.
Phil.

Mr.Penfold

Awesome thanks! I couldn't get my head around the three terminal fuse connection and wiring, makes sense now that I know it's not actually for a fuse...
I'll just go ahead and use the single voltage terminal I have, found on the side of the transformer saying the red is for the 240V, cheers!

About to wire it now so hopefully should be all good

phatt

Great to hear you have it sorted out :dbtu:
Phil.