Morning all, I'm after a little help and struggling to figure this out. I have what looks like a blown resistor on a PCB.

It's a 5 band and looks to be Brown, Black, Brown, Gold and then Black. The tolerance is confusing me (sorry, not my field of expertise). It's from a PCB in a boiler switch. I have another one which is working and the resistor in that gives a reading of 101 ohms on the meter.

Image provided.

Can alone help me identify it so I can source a replacement?

Thanks in advance for any help you might provide.

Paul

 

Yes it should be 100 ohms 5%..

 

Thanks for that, swift!!!!

So could I replace with something like this:

https://uk.rs-online.com/web/p/through-hole-fixed-resistors/1067176/

Thanks.

 

Yes it should be 100 ohms 5%..

Another question, would you mind explaining why this is 100ohms and not 10? If I put the Br,Bl,Br,Go through a four band resistor calculator it correctly comes out at 100 ohms, what does the last 5th black band mean? Thanks. P

 

And on that basis, this is the spec of the replacement resistor by the look of it:

https://www.amazon.co.uk/700V-Metal-Oxide-Resistors-Through/dp/B0087ZE4T8

 

Yes any 100 ohms 5% 3W resistor will do,,


https://cpc.farnell.com/multicomp/m...und-100r-5-3w/dp/RE07369?st=100 ohms resistor

 

Last one promise. I have a 5W in stock, can I use that?

 

Yes, any Wattage higher is better..

 

The most important question is yet to be asked,why did it blow?
When the resistor is replaced and circuit is function properly count your blessings. If not that's when the fun begins.

 

@ brumster
Nice photo.

 

Photo taken under a magnification lens using an iPhone XS

It's a boiler switch and it looks like the earth screw inside the casing has worked it's way loose, that in turn has caused a short, from there my limited knowledge has identified that the component in question (the resistor shown above) has blown, a meter across the pins shows 0. Remember that the image above is from a working identical switch, the resistor in question has visible signs of damage.

Hopefully a replacement resistor will bring it back to life, if not then you're right, the fun begins or I source another. But, can I be that lucky!

Thanks for all the replies, great community!

 

, can I be that lucky

Luck favors the prepared, and you good sir have an arsenal at your disposal!!

 

@brumster,
I suspected that was the good resistor.
With a spare unit, you can compare readings.
Think lucky and you will be lucky. (Or words to that affect).
Good luck.....

 

Black band on the end is likely the temco. Black = 250 ppm/K

 

Do you have any idea where I can source an identical replacement?

I have a 100ohm 5w on its way but I’m guessing I’d be best if with a direct replacement?

This is what I was intending to replace with:

https://uk.rs-online.com/web/p/products/1870019/

Thx. P

 

Now sure how it was determined that the part in question was a 3W, but assuming it was, and the 5W art you ordered will fit, then it is a fine replacement.

 

Me neither, if size has anything to do with it then it possibly was a 3W as the 5W replacement is slightly larger than the original component.

Everyone likes an update (I do anyway) so here's how I got on......

The unit in question is a Hive Heating SLR Receiver (the boiler switch).Model is Hive SLR1 Receiver.

I ordered the replacement part yesterday from RS and it arrived today. The first image below shows the failed component. The second image showing the fitted replacement, as you can see slightly larger in size. I powered the unit up (using a dim bulb tester) and it powered up immediately. It has now been fully reset, tested and re-added to the home heating system.

To all those above that took the time to help me out a very large thank you! Really appreciated!