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Like a MELF, but larger?

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tomizett

Active Member
Hi All,
Another dull question about identifying and sourcing parts from me today, I'm afraid.

I have a piece of equipment for repair that uses large cylindrical surface-mount resistors of the MELF style - which I need to replace.
The problem is that they are larger than any MELF-style resistor that I can find listed by manufacturers or suppliers. Although I've seen resistors of this style before, I've never (that I remember) had to replace any.

The resistors I'm looking at are 10.5mm (0.41") in length and 4mm (0.16") in diameter.

Information that I've been able to find (like http://www.resistorguide.com/resistor-sizes-and-packages/) list only MELF, MiniMELF and MicroMELF, all of which are significantly smaller than this.

So, does anyone know what the name of this package is and where in the UK I might be able to source them? Failing that, can anyone suggest good alternatives? The value, in case it matters, is 3k3.

Thanks as always,
Tom.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Are the original resistors actually faulty?, it sounds a pretty unusual occurrence.

Assuming they are faulty?, can you not replace them with normal resistors?.
 

tomizett

Active Member
Hi WA6MOK, thanks for the info.
I was going to suggest in jest that they could be called a "Maxi-MELF"... seems like I was right. RS in this country don't have them as far as I can tell (they're our preferred distributor) - I'll need to have a good look at Farnell and then Digikey, Mouser etc.

Hi Nigel,
The original resistors have run very hot - the enamel is cracking and at least one of them has drifted out of spec. At the moment I don't know if this is due to a fault condition, but I have a suspicion that they might just be a little under-rated for the job. If that's the case then there's obviously a case for replacing them with something a little larger - on the other hand, I generally like to give the designer the benefit of the doubt that they knew what they where doing, and fit the original parts - if nothing else, it makes for a neater repair.
The irritation is that they're on a soldered-in daughterboard and I'd like to replace the overheated Rs before I solder the board back in and move on to diagnosing the reported faults - otherwise, not only do I not know if the fault is due to out-of-spec resistors, but I'll also have to remove the board again in order to replace them before the job is complete.

All in I think I may just find some larger through-hole parts if the maxi-melfs aren't readily available.
Thanks guys.
 
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