what fuse do I need, yamaha emx66m

[ciarancussen]

I'm confused on what fuse i need for my mixer. It says F1Al 250V on the blown fuse (took out in photo). any help appreciated... https://drive.google.com/file/d/1oC0x5L ... sp=sharing

[Mike Stranks]

Welcome!

The 'blacked-out' info on the circuit board is stating a 1.2 amp 250 volt fuse. But why it's blacked-out I'm not sure...

Do you know why the fuse blew?

[Tomás Mulcahy]

Are you in the UK or US? Is the unit the 110V or 250V model?

[Hugh Robjohns]

I'm confused on what fuse i need for my mixer. It says F1Al 250V on the blown fuse (took out in photo). any help appreciated...

The general rule is you replace like for like... An F1A fuse is a 1 amp quick-blow (fast) fuse. Given Mike's detective work, it looks like you could possibly increase that to F 1.25A.

The question is, why did it blow? Fuses can just spontaneously die through old age or vibrational fatigue in mobile gear... but usually they blow because of a fault.

[ciarancussen]

It’s a 250v version. Not sure why the fuse blew as I got the mixer with some speakers second hand.

[Hugh Robjohns]

Had it been working normally for extended periods without issue before the fuse went? Any indication of a problem -- smoke, nasty noises, high temperatures -- before it blew?

[BJG145]

The 'blacked-out' info on the circuit board is stating a 1.2 amp 250 volt fuse. But why it's blacked-out I'm not sure.

That's really weird. That's bugging me now.



^^^

What they say. Stick in another one and cross your fingers.

[wireman]

The 'blacked-out' info on the circuit board is stating a 1.2 amp 250 volt fuse. But why it's blacked-out I'm not sure.

That's really weird. That's bugging me now.

I assumed that only one was supposed to be blacked out based on supply voltage.

[BJG145]

Ingenious. I'll buy that. They started redacting and got carried away,

[BJG145]

...now, I don't know anything about fuses. But one thing they didn't scribble out is: "T4A". As far as I can see from a bit of Googling, this is "slow-blow", but the one you took out is "F1A" which is "fast-blow".

The game's afoot.

[Mike Stranks]

Dr Watson here...

This is the relevant bit of the service manual:



Full manual available at: https://drive.google.com/file/d/1xnYSPSF7Tm1iYmctkVIgHUGtl_Ljj7b1/view?usp=sharing

[AlecSp]

Tranceformer - magic!

[BJG145]

Dr Watson here

...except...



You know my method. It is founded upon the observation of trifles.

[BJG145]

Looking back to an earlier page of the service manual, there's this:



What is all this J and U stuff...? Are these descriptions for the fuse in different versions of the circuit board...? It's not very clear. But it seems quite plausible that the one you removed blew because it's the wrong type.

[Hugh Robjohns]

Looking back to an earlier page of the service manual, there's this:

It's quite likely the same raw PCB is used in multiple designs with different ratings. Hence the crossed out options.

But it seems quite plausible that the one you removed blew because it's the wrong type.

Hence my earlier question: Had it been working normally for extended periods without issue before the fuse went?

And: Any indication of a problem -- smoke, nasty noises, high temperatures -- before it blew?

If it had been working normally before hand, the removed fuse was probably the right value (or close to it). Ditto if the unit developed an obvious fault immediately prior to it popping.

But reading the specs for that unit, with such a large inrush current, I was surprised it was an F (fast-blow) fuse... I would have expected a T (anti-surge) fuse.

[James Perrett]

Chances are they use the same board for a number of different models so the fuse rating depends on which model the board is fitted to.

Looking at the parts list, the 12A and 10A fuses are for the Japanese and US versions while the Northern European version uses a TSD 4A 250V SEMKO 20mm fuse.

[ciarancussen]

I put in a 1.25amp fuse in today and it blew straight away without time to even show a light on the mixer. So will I try a 10amp then a 12 amp?

[Hugh Robjohns]

I put in a 1.25amp fuse in today and it blew straight away without time to even show a light on the mixer. So will I try a 10amp then a 12 amp?

I wouldn't... That path leads to smoke and flames!

It's really important to know if it ever worked reliably, in your ownership, with the original fuse fitted?

I fear not and that you've picked up a second-hand dead mixer-amp.

There is some evidence that it might be intended to use a T4amp fuse (time-delay or anti-surge 4 amp), so it would be worth trying one of those, but definitely NOT a 10 or 12 Amp fuse of any description.

But the fact that it came with a dead fuse and blows a similar replacement instantly suggests a catastrophic fault condition.

[ciarancussen]

It never worked in my ownership. I’ll try the anti surge 4 amp fuse.

[ef37a]

It never worked in my ownership. I’ll try the anti surge 4 amp fuse.

No! That powered mixer has a consumption rating of 300W which would indicate a 1.25A fuse for a 240V supply. You could go to 2A (and slow blow as Hugh thinks) but I am pretty sure that will blow as well and you have a serious fault with the mixer.

Fusing equipment is far from an exact science and often ratings have to be changed, almost always increased after gear has been out in the real world a while. It should be remembered that fuses are NOT there to save the electronics so much as to stop fires! Well they do tend to save very expensive things like power transformers.

Dave.

[James Perrett]

It never worked in my ownership. I’ll try the anti surge 4 amp fuse.

No! That powered mixer has a consumption rating of 300W which would indicate a 1.25A fuse for a 240V supply.

4A anti surge is what the service manual says Dave.

Personally I would do a few checks with a meter first before replacing the fuse.

[ef37a]

It never worked in my ownership. I’ll try the anti surge 4 amp fuse.

No! That powered mixer has a consumption rating of 300W which would indicate a 1.25A fuse for a 240V supply.

4A anti surge is what the service manual says Dave.

Personally I would do a few checks with a meter first before replacing the fuse.

But it also gives the 240V mains consumption as 300mA? 4 amps is getting on for a kW and a 4A T would need near ten amps to blow. There clearly IS some confusion here and fitting such a fuse rating before checking things could destroy many more components, even blow print away.

The OP might be lucky and the fault nothing more than a shorted 100nF mains filter cap although if the right type, X or Y is fitted they rarely fail in my experience.

https://www.cricklewoodelectronics.com/ ... 7xEALw_wcB

^ Shows the rear panel of a 300+300W amplifier and the fuse for 240V is T2A. Since this is a mixer maybe T2.5A? 4A is for 110V operation.

Dave.

[Mike Stranks]

I think this has moved beyond an interesting discussion that we've all been having about fuses...

The O/P has said that the mixer-amp has never worked in his ownership. It's blowing the specified fuse straight away.

Time either for the O/P to start negotiations about getting his money back if that's possible or to have the amp properly checked out by someone who can determine where the fault lies. We've even made a service manual accessible!

... any other route risks a merry blaze or a possible minor fault becoming a 'fit only for the scrapheap' one.

[Hugh Robjohns]

Yep -- completely agree with Mike.

And Dave makes a good argument about the T4A fuse...

This really isn't the time for random fuse swapping. If it has never worked under the current ownership then it should be assumed to have been sold with a fault.

Fitting ever larger fuses is likely to convert what might be a minor fault into a catastrophic failure that is extremely uneconomic or even impossible to fix.

I'd recommend either returning the unit to the vendor or find a competent technician and be prepared to spend a load more money on it!

[BJG145]

The 'blacked-out' info on the circuit board is stating a 1.2 amp 250 volt fuse

But the circuitboard and diagram say "10A" and "12A", not "1.2A". Is it common to leave out the decimal point...?

The other circuitboard shows "2A" for that other fuse, not "20A".