Need help identifying a diode

[DKMurphy]

I have a diode that I need to replace on a Powermax RacMax surge protector. I'm having a hard time finding a replacement diode. It is black with a brownish/gold band on the anode. It has metalic blue markings

Tf 104 (degrees) c
D103PCRT

Below is a picture with a nickle for scale. Any help you can give me would be appreciated. I'm an intern and this would make me look really good if I get this fixed at the component level. THANKS!!

 

[john monks]

Can you supply a picture of the inside of your device?

 

[CocaCola]

The photo is really out of focus, is there any color banding on it besides the gold one?

 

[DKMurphy]

The photo is really out of focus, is there any color banding on it besides the gold one?

No color Banding besides the gold. Only camera i have right now is crapy cell phone. Will Post inside pic later.

 

[(*steve*)]

It looks like a thermal fuse to me.

My guess is 104C, but that seems quite low... (but surprisingly, it's not)

look here.

edit: Check the specs here. The one suggested above can hold at 106C, perhaps (almost certainly) you want the one that breaks at 104C (can hold at 80C)

Note that second one I suggest has a yellow end. That may correspond to the yellow band. Maybe someone can tell us if there's a colour code for these things.

 

[CraziestOzzy]

as said...thermal fuse
...and if I know Chinese manufacturing, it's under-rated for it's task and designed to fail with the added bonus that it's manufactured on the cheap with no thought on quality giving it and the unit it services (Powermax RacMax surge protector) a short life-span
You can replace it with one from a reputed manufacturer with a local distributor.
I have seen one too many different failed electronic rubbish with same fault...that of a cheap fuse or a fuse in place that is not needed but designed to fail the product after a time or a fuse that is under-rated for it's task.
Any chance of seeing it's place on circuit in a mud-map or a photo? Will help with determining the correect current and thermal rating you need and if you indeed need one at all.

 

[CraziestOzzy]

Note that second one I suggest has a yellow end. That may correspond to the yellow band. Maybe someone can tell us if there's a colour code for these things.

there are no colour codes for thermal fuses like there are for resistors. Colour codes are manufacturer dependant.

 

[DKMurphy]

Thanks for all the help. I'll post a picture of the circuit later today. Sorry for not replying sooner, but I don't come in every day.

Yes, it does appear to be a thermal fuse. I tested it on my multi meter and its a short and the other 2 that were in the circuit worked fine, and acted not at all like a diode would.

I soldered in a piece of wire in place of the thermal fuse and it worked fine. The problem originally appeared to be a blown varistor, which I replaced. But the thermal fuse also failed.

This is from a Powermax Racmax surge protector btw. Thanks again for the help. I wasn't familiar with varistors or thermal fuses before working on this. Learning new things is always fun. Your guys help allowed me to solve the problem. Thanks!

DKM