Trying to ID this resistor as cannot seem to find.

Thread Starter

daveglas

Joined May 19, 2019
5
Quick back story.

Some type of insect crawled into my washing machine control module and fused itself to the coil and a resistor.

So I am trying to fix, but I cannot locate a resistor.

The resistor I need is listed on the circuit board as R235.
Red, Green, Black, Gold .
25ohms 5%
resistor body measures 4.9mm x 13.5mm

But any search I do bring up nothing like the resistor I have.

Thank you in advance for any help.
David
 

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bertus

Joined Apr 5, 2008
20,044
Hello,

The first color is brown and not red.
Then the value would be 15 Ohms, wich is a standard value.

Bertus
 

ericgibbs

Joined Jan 29, 2010
8,719
hi,
Looking at the image of the damaged resistor, it looks wire wound, so I would say 15R at 2W to 3W,
E
 

Thread Starter

daveglas

Joined May 19, 2019
5
I have attached a better image as I am getting really confused as to why they marked the board as R253 (sorry error in the OP not R235)

Don`t want to have to spend £70 for a replacement module.

Thanks again
David
 

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Sensacell

Joined Jun 19, 2012
2,437
Don't be surprised if replacing the resistor doesn't fix the board.

Resistors are simple and robust, a short would likely damage the sensitive components, like chips and transistors first.
This damage isn't visible in most cases.
 

Thread Starter

daveglas

Joined May 19, 2019
5
Don't be surprised if replacing the resistor doesn't fix the board.

Resistors are simple and robust, a short would likely damage the sensitive components, like chips and transistors first.
This damage isn't visible in most cases.

I know, but its fun to try to make things work for cheap again. I am sort of hoping that considering the amount of voltage that must go through this board and the amount of heat it generates that it might have survived this little short.

Thanks all. I will get some suggested resistors ordered.

David
 

Tonyr1084

Joined Sep 24, 2015
3,572
I have attached a better image as I am getting really confused as to why they marked the board as R253
Circuit boards have a lot of components on them. When manufactured it's important to know which resistor goes where and how many of the same type of resistor is needed. R253 is just an identifier relating to the bill of materials (BOM). If you can find the BOM for the board all you have to do is look down the list for R253 then read across to get its value and rating. You'll see the same sort of markings for capacitors (C1 for example, doesn't mean 1 µF or relate to any value or ratings, it's just the first cap on the list). Diodes = D1; IC's = U1; Transistors (typically but not always = Q1); on and on. Fuses, relays, connectors (J1 & P1 typical). Nuff bout that.

If you can get a shot of the damaged section that would be helpful in diagnosing the likelihood of other possible damage. If this IS a wire wound resistor then it would take tremendous current to burn it out like that. It's very possible other components couldn't survive whatever it takes to burn out a wire wound resistor. However, I have personally seen a burned resistor smoke due to a shorted component like a power transistor or something else like a shorted cap. It's quite possible this little bug caused a cascading failure in the board which culminated in the failure of a power resistor, effectively shutting down power to this board. The burned resistor is just the last bit of evidence of damage. I think you're going to find unsatisfying results replacing the resistor. Take it out and put a light bulb in its place to see what happens. Also measure any voltage at that light bulb. If it glows brightly then that MAY hint at other issues on the board.
 

Thread Starter

daveglas

Joined May 19, 2019
5
Circuit boards have a lot of components on them. When manufactured it's important to know which resistor goes where and how many of the same type of resistor is needed. R253 is just an identifier relating to the bill of materials (BOM). If you can find the BOM for the board all you have to do is look down the list for R253 then read across to get its value and rating. You'll see the same sort of markings for capacitors (C1 for example, doesn't mean 1 µF or relate to any value or ratings, it's just the first cap on the list). Diodes = D1; IC's = U1; Transistors (typically but not always = Q1); on and on. Fuses, relays, connectors (J1 & P1 typical). Nuff bout that.

If you can get a shot of the damaged section that would be helpful in diagnosing the likelihood of other possible damage. If this IS a wire wound resistor then it would take tremendous current to burn it out like that. It's very possible other components couldn't survive whatever it takes to burn out a wire wound resistor. However, I have personally seen a burned resistor smoke due to a shorted component like a power transistor or something else like a shorted cap. It's quite possible this little bug caused a cascading failure in the board which culminated in the failure of a power resistor, effectively shutting down power to this board. The burned resistor is just the last bit of evidence of damage. I think you're going to find unsatisfying results replacing the resistor. Take it out and put a light bulb in its place to see what happens. Also measure any voltage at that light bulb. If it glows brightly then that MAY hint at other issues on the board.

Thank you so much for your advice. I soldered in a bulb but nothing so it seems like the board is dead.

So annoyed as the machine is less than 3 years but the fault is nothing to do with the product as such, just a really really weird accident.

I think I will pop out tomorrow and get another one (same model) and then at least I have some spare parts if and when I may need them.

Thanks again all. Really please I found this forum as I have some small arduino projects waiting for me and finding such a friendly place to get advice if I need it is fantastic.

David
 

Tonyr1084

Joined Sep 24, 2015
3,572
@daveglas WAIT A MINUTE! Just because the bulb didn't light doesn't mean the board is shot. IF the light had lit I would assume the only failure point would have been the resistor. At least that would have been a starting premises. But because the light didn't light up - doesn't mean the board is shot.

Honestly, I think it is. But thinking from across the country (or planet) can't diagnose the problem. Did you check for voltage on the bulb?
 

Thread Starter

daveglas

Joined May 19, 2019
5
@daveglas WAIT A MINUTE! Just because the bulb didn't light doesn't mean the board is shot. IF the light had lit I would assume the only failure point would have been the resistor. At least that would have been a starting premises. But because the light didn't light up - doesn't mean the board is shot.

Honestly, I think it is. But thinking from across the country (or planet) can't diagnose the problem. Did you check for voltage on the bulb?

I did, I also checked for continuity across some of the circuits. I had to make the decision regarding how much time this would take me,along with how much we need a washing machine. Also the fact that the surge created was enough to blow one of my breakers just made me a little worried about anything else that may be wrong.

I may mess around with the board in my spare time and repair if possible and make some money back reselling if I can.

Again thank you so much for your advice and help.

David
 

MaxHeadRoom

Joined Jul 18, 2013
19,005
I may mess around with the board in my spare time and repair if possible and make some money back reselling if I can.
David
May be worth hanging on to as a spare?
Is it possible to post a pic of the board?
Have you checked the foil side of the board?
Max.
 

Tonyr1084

Joined Sep 24, 2015
3,572
May be worth hanging on to as a spare?
Funny you should say that: I had a dishwasher controller board go whonky on me. Sometimes it would lock up and do nothing, and I had to cycle the breaker to clear the freeze. Decided the wife wasn't going to live with that I bought a new control board. Worked for 5 years. Meanwhile the old board sat in my scrap boards drawer. Just a few months ago the new board began to malfunction. It would't do anything. Even cycling power didn't clear the issues. So I ordered another control board. Meanwhile I thought I'd just throw the old original board back into service and it worked well enough for two weeks while I waited for the replacement to arrive. The NEW new board is in, the old ORIGINAL board is back in my scrap boards drawer along with the second controller board. It has some relays and some power components that may one day come in useful.

It's always worth hanging on to something that may either provide parts - or in a jam, serve as was intended for short periods of time.

Well, it's off to the garage to give attention to my latest project - my wood shop dust collection project. Some of you may know what I'm talking about.
 
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