Fusable Resistor ID and Sourcing

[98PaceCar]

I'm working on fixing a Zemmix I just bought and have tracked down that I have at least a dead fusible resistor in the ac side of things. Do the color bands on these follow the normal color codes for other resistors? Are there any good online sources for these?

[channelmaniac]

Got Pic?

If it's truly a resistor then it would be burnt and you would have a hard time reading any color codes on it.

RJ

[jb143]

If you find the values you need, I should be able to source the parts for you(That's what I do for a living). Just let me know.

[98PaceCar]

Hey RJ,

I didn't realize you hung out here too. Cool!

I don't have a pic, but will get one tonight. If I had to describe it; take a standard, glass, automotive fuse and put a resister inside the glass. It does have the normal spring looking deal at one end, like you would expect in a normal fuse. The fuse holder and fuse itself both read .2a and if I read the bands on the resister correctly, it's a 91 ohm 1%.

I tested it several times with my meter and it always read open, so I'm guessing it's either damaged or blown.

@JB143, I may very well take you up on that. Thanks for the offer of help!

[jb143]

What is the color code on it? The 5'th band should be white for a fusible. Other than that I'm pretty sure they're read the same way.

[98PaceCar]

I don't have it with me, but I'll post it when I get home. I do believe the 5th band was white like you said.

[98PaceCar]

Well, my pictures all came out really bad, so I'm not going to waste the bandwidth yet. I did recheck the bands and they appear to be:

White
Brown
Black
Gold
Brown

The fuse portion doesn't appear to be burnt, but it is reading open.

[jb143]

I was hoping to see a picture but I understand it not comming out good. My camera does horrible on closeup shots. Could you describe it better? I've never seen one inside a regular fuse packaging. It's like a basic glass tube fuse? Is there any indication on the PC board, like FR###?

Your probally right about the 91ohms 1%. That's what the standard color code would be anyways. The white band in this case looks to be a regular white band.

Also, if it is a fusible resistorsor (or possibly a flame proof resistor) then it wouldn't go up in smoke and burn up like regular ones. It would do as you described and read as open. I can try to find one but so far I havn't turned up anything. Not 91ohms anyways, and not in the packaging you described. I'd like get more information on it to make sure I find the right thing since you really need to replace it with the correct part.

[98PaceCar]

I was hoping to see a picture but I understand it not comming out good. My camera does horrible on closeup shots. Could you describe it better? I've never seen one inside a regular fuse packaging. It's like a basic glass tube fuse? Is there any indication on the PC board, like FR###?

Your probally right about the 91ohms 1%. That's what the standard color code would be anyways. The white band in this case looks to be a regular white band.

Also, if it is a fusible resistorsor (or possibly a flame proof resistor) then it wouldn't go up in smoke and burn up like regular ones. It would do as you described and read as open. I can try to find one but so far I havn't turned up anything. Not 91ohms anyways, and not in the packaging you described. I'd like get more information on it to make sure I find the right thing since you really need to replace it with the correct part.

I had some better luck tonight! Turns out, macro mode is made for this (it really pays to have a semi pro photographer for a fiancee!)!

The fuse itself was held in one of the cheap inline fuse holders that is in between a transformer and a switch to select the voltage (100 or 220). The two piece, spring loaded, twist apart kind (I can snap a pic if you like). It is specifically marked as .2a with a sticker, but nothing else on the holder. This matches the rating on the end of the fuse (250v, 0.2 a). The line in question appears to be the 100v input and runs to an internal transformer.

Here's the pic, sorry for the size, but it does show the detail of what it is.



I really do appreciate your help on this. I'd love to get this running!

[channelmaniac]

It's a fuse all right...

What writing do you see stamped on it? That will tell you the type of fuse (GMA, etc...) which will make it much easier to find.

A quick look in the Newark catalog reveals a 313P series 3AG SLO-BLO Cartridge Fuse by Littlefuse. BUT... your picture looks like the fuse is shorter than a standard size.

There are other slo-blo type fuses, but not any that looked like they had a resistor or inductor inside. Unless it's an odd value you should be able to put a standard slo-blo type fuse in place of it.

RJ

[jb143]

OK, I think that's actually a current limiting fuse. They are designed to open faster than normal fuses in case of a short so nothing else gets damaged by a higher current. You might be able to get away with using a standard type fuse but I'll see if I can find a low purchace quantity(1) source for you.

[98PaceCar]

Hehe! Glad to know I'm not completely crazy!

I did see that it's a 250v 0.2a, but I didn't make note of the other writing that was on it. I'll do that tonight.

It is a bit shorter than what I've seen in the automotive world. I haven't checked it against my stash of arcade fuses, but I'm thinking it's shorter than those as well. I'll measure it when I get home tonight.

@jb143, if you can find an exact replacement, I'm not against buying a larger number of them. I don't have much need for 250 or 500 of them, but if it's a smaller minimum or even a minimum dollar amount, I'm game for that.

Thanks guys!!!

[jb143]

Just a thought since the fuse it'self doesn't look blown. Did you read resistance across it, or just test for continuity? 91ohms might be just enough resistance that a continuity tester wouldn't make a sound. If the fuse is still good it should read around 91 ohms.

[98PaceCar]

I did check for resistance and it's reading open. Even did it both ways, just in case it's doing something odd on me. Same result both ways.

[98PaceCar]

There are some other markings on this, but it appears to be Korean. It's nothing that I can make out. The overall length is .75 of an inch.

RJ, if you want, I'll be in your neck of the woods in the next few days. I can swing it by. I'm real curious to figure this one out now.

[jb143]

I havn't found an exact replacement yet, but I also havn't had much time to look. The common catalog places(digikey, mouser, etc...) don't seem to carry them. If you do replace it with a regular 250V 200mA fuse though, I'd definatly use a fast acting instead of a slo-blo.

[channelmaniac]

There are some other markings on this, but it appears to be Korean. It's nothing that I can make out. The overall length is .75 of an inch.

RJ, if you want, I'll be in your neck of the woods in the next few days. I can swing it by. I'm real curious to figure this one out now.

I'll be at the First Saturday sale tomorrow in Downtown Dallas. If you're down that way, bring it by. Also, you should check at Tanner Electronics over on Valwood, just west of I-35E in Farmer's Branch. (Valwood exit is just north of 635 on I-35E.)

[98PaceCar]

I took the dead fuse over to the local parts supplier (Tanner) and the guy there found what appears to be a suitable replacement. It's actually a 250ma fuse, but worked fine when I put it in the dead Zemmix. Fortunately, it appears this has fixed the problem for the system. My guess is someone plugged it in to a 220v source while it was set for 100v. I played around with it for 15 or 20 minutes and didn't notice any excessive heat or any other issues. I won't be playing with it much, but it's good to know that it does work!

Thanks for all the help guys!

[channelmaniac]

Always glad to help where I can.