Help Required To Identify Electronic Component

Thread Starter

Clive Long

Joined Aug 29, 2014
12
Hi,

I do not have electronics knowledge. I am trying to get a small PCB repaired in a food processor. Some bits of what I would call "resin" have fallen out of the device when I removed the base. There are a few numbers and letters on the resin that might help identify the device.

RA2JP, 250V and X2

I have had a poke around the internet for those codes and they might be the numbers from a capacitor but that's really only a guess. I can take out the PCB and see if there is any further information left on the component that shed this resin.

Am I likely to have any chance of identifying this component, getting a replacement part, and having a stab at a repair?

Thanks,

Clive
 

Thread Starter

Clive Long

Joined Aug 29, 2014
12
A photograph of the top and bottom side of the board may help?
Thanks,

I will have a go at taking out the board tomorrow and photographing. I am assuming placing the picture on a public file share then posting the link will be enough to make the image visible as some forums don't allow posting of pictures inside posts.

Clive
 

paulktreg

Joined Jun 2, 2008
786
The site has very recently changed to Xenforo so there have been a few minor problems and I'm not sure on what policy is on posting images. I'm sure links will be OK.
 

Nykolas

Joined Aug 27, 2013
115
The little description the OP offered make me believe it could be a TVS (transient voltage suppressor) or a MOV (metal oxide varistor). Check the GE, Raychem, Citel, Semtech and other websites for product ID. E
 

#12

Joined Nov 30, 2010
18,210
I'm guessing it's a power line rated dual capacitor, but I can't tell the size from the first post. The RA2JP eludes me.
 

Thread Starter

Clive Long

Joined Aug 29, 2014
12
Hello,

Thanks for all your replies.

I just can't get access to the circuit board. It is in a slot which is blocked by the motor and the motor is somehow fixed to the case but not by a screw. I have attached a couple of pictures but you can't see much. In the closeup picture what you see is the component with a "tear" down the centre. More of the resin cover came out and two pieces when put together spell out 0.1uF (as much as I can work out). I will spend another half an hour fiddling around with the case to see if there is an obvious way to get the board out but I am not hopeful given the hour I spent today. Then it is the landfill for the food processor - which is a shame because I feel probably a £10 soldering iron and a £2 component could fix this.

https://dl.dropboxusercontent.com/u/32576758/FP base off.jpg

https://dl.dropboxusercontent.com/u/32576758/Capacitor close up.jpg

Regards,

Clive
 

ISB123

Joined May 21, 2014
1,236
White block behind in the shadows looks like a capacitor,brownish thing next to it looks like small PCB mounted transformer similar to ones found in chargers and it looks like its blown.
 

b1u3sf4n09

Joined May 23, 2014
113
Can you post a picture of the other side of the food processor? There is probably a screw or plastic clip that is holding the motor housing in place that you will have to unfasten. Once removed, you should be able to have an easier time at diagnosing the damage. From your picture, I'm going to agree with ISB123: It looks like a transformer failed. Also, the other 2 components I can see (brown and blue) look like MOVs.
 

Thread Starter

Clive Long

Joined Aug 29, 2014
12
Ok, I have finally taken it apart. There were two plastic lugs holding the cover to the body that I managed to prize open using an old hacksaw blade (without breaking the lugs !!). When the top cover was off, a final large screw was revealed that was holding the motor to the body. Removed that and some more screws and the motor dropped out and the PCB was slid out.

The images are:

https://dl.dropboxusercontent.com/u/32576758/DSCF2135.JPG
https://dl.dropboxusercontent.com/u/32576758/DSCF2136.JPG
https://dl.dropboxusercontent.com/u/32576758/DSCF2138.JPG
https://dl.dropboxusercontent.com/u/32576758/DSCF2139.JPG
https://dl.dropboxusercontent.com/u/32576758/DSCF2140.JPG
https://dl.dropboxusercontent.com/u/32576758/DSCF2141.JPG
 

#12

Joined Nov 30, 2010
18,210
I'm sticking with the power line rated capacitor, except it's not a dual capacitor. It's the same as the one next to it: 0.1 uf rated at 250 volts AC

Problem is, if a power surge blew this one to pieces, you probably have worse problems. The machine should run without the protective capacitors. Take the remains out and see if the machine will run. If not, you've only just begun to find out what's wrong.
 

Thread Starter

Clive Long

Joined Aug 29, 2014
12
Yesterday the motor did run smoothly for about 30 seconds. I then released the "pushdown" switch. I then tried running the motor again and the motor turned for less than 1/4 second and stopped. I tried again twice and the motor no longer turned. I was concerned about doing more damage to the circuit by leaving power on as I didnt know the purpose of the blown component. As you have written, whatever caused the component failure might have damaged other components on the board. However, if the failed component can be identified and replaced then I will be able to see if I can get the motor running again. If other components have failed, but not visibly, I don't have the knowledge to test them one by one to determine if any of them should be replaced. So if a replacement capacitor / transformer can be suggested at least I can try that. At this stage just identifying what the component is a source of debate. Are the numbers and letters from the resin fragments any use in identifying what it was?

Regards
 

MaxHeadRoom

Joined Jul 18, 2013
21,194
That is a Universal motor and the controller is most likely a simple Triac control, it should be very simple to reverse engineer it based on the very few components there.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
21,194
So if a replacement capacitor / transformer can be suggested at least I can try that. At this stage just identifying what the component is a source of debate. Are the numbers and letters from the resin fragments any use in identifying what it was?
Regards
Looks as though you need a 0.1µf 250v AC RATED capacitor.
250v minimum, higher even better.
Max.
 

bertus

Joined Apr 5, 2008
20,651
Hello,

As the capacitor was a X2 rated capacitor, you should replace it with the same type.

Class X is for applications where failure could not lead to electric shock (hot to neutral). Class X1 capacitors are intended to operate safely even in the presence of spikes on the mains supply of up to 4 kV (installation category 3 or overvoltage category 3 according to IEC60664), which are normally industrial supplies, but some standards call up class X1 capacitors if they are connected directly to the mains supply upstream of the equipment fuse, irrespective of the type of mains supply. Class X2 capacitors are intended to operate safely even in the presence of spikes on the mains supply of up to 2.5 kV (installation category 2 or overvoltage category 2 according to IEC60060), which are normally residential, commercial and light industrial supplies. X capacitors can be found from 0.001 uF to at least 10 uF and are only made in film.
This quote comes from this page of the capsite:
http://my.execpc.com/~endlr/line-filter

Bertus
 

Thread Starter

Clive Long

Joined Aug 29, 2014
12

Thread Starter

Clive Long

Joined Aug 29, 2014
12
Hello,

I bought a replacement capacitor from Maplins and it looked completely different to the original on the board. I checked the part and they are convinced this is the right one. Nowhere on the object is there 0.1 uF !!

https://dl.dropboxusercontent.com/u/32576758/Replacement capacitor from Maplins.jpg

So, I took out the old capacitor and tried to fit the new one. They are completely different sizes. However, amazingly, there is a secondary hole on the PCB on the same trace (is that the right word?) that the replacement can be fitted to, so I decided to give it a go. You can see the original hole on the PCB to the right of the new component.

https://dl.dropboxusercontent.com/u/32576758/Capacitor swapped and broken resistor.jpg

When I reconnected everything and switched the device on the motor ran beautifully for a few seconds then stopped. Now when I switch on the motor might turn once every 10 attempts and then it turn for less than a quarter of a second and then stops. I thought, " that's it, it's buggered."

Tonight I had another look at the board and noticed the resistor next to the replaced capacitor was cracked, I hadn't noticed this before. If one looks back at the original photo the crack is there in the resistor, so it didn't happen as a result of the new "capacitor"

https://dl.dropboxusercontent.com/u/32576758/Original resistor upclose 2134.jpg

And here is the resistor off the board

https://dl.dropboxusercontent.com/u/32576758/Broken resistor.jpg

So, maybe a replacement resistor will fix it.? As far as I can tell the colours are: Green, blue, black, Silver,

which an online ready-reckoner comes up with 56 Ohms 10%

Does this look an ok resistor? http://www.maplin.co.uk/p/metal-film-06w-56-ohm-resistor-m56r

There isn't any other 56Ohm resistor on the Maplins site.

So I will try that next. Everything else looks ok, but might not be. Some items are so small and with no markings its impossible to see what they are. So if replacing the resistor doesn't fix it, I'm stuck.

Thanks

Clive
 
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