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DIY RC Filter replacement

ssjenkins

Feb 20, 2020
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Hi All !

I want to replace these RC units from an old fruit machine . 0.1uF + 47 ohm 250V . The problem is that I have 25 of them to change , and looking at RS , that's going to cost me about £80 which I'm not willing to pay . Could I just hook up a cap and resistor in series for each one ? I know it won't look so pretty , but I can't justify the cost for the repair . Any suggestions ?

Sammy
 

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Hunter64

Nov 20, 2018
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Just replace them, or wait for the fireworks!

These capacitors are guaranteed to fail.
 
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Tha fios agaibh

Aug 11, 2014
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Could I just hook up a cap and resistor in series for each one?
I don't see why not.
Just use axial caps and solder the resistor on one end, then cover with heat shrink tube.

They likely need replacement due to age but how did you test them?

Edit: I just saw 2nd picture. Strike "likely"
 
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Tha fios agaibh

Aug 11, 2014
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Good point about the safety caps.
Even if X2 caps are used, it roughly 1/3 the cost of replacing with an oem snubber.
 

ssjenkins

Feb 20, 2020
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Many , many thanks for all the replies . The ones that are in it are X rated , but I'll have a look for X2 rated ones on the RS website .

Sammy
 

ssjenkins

Feb 20, 2020
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Thanks martin . Could someone give me a link or 2 to some suitable components and I'll have a look .
 

Martaine2005

May 12, 2015
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X2 caps are readily available on all sites or shops. As are the resistors.
Your post code (zip) will indicate your local electroniics store.

Martin
 

Tha fios agaibh

Aug 11, 2014
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You wouldn't be able to solder it in.
I'd use an axial type cap and solder one lead in one hole, and the resistor in the other. Then solder the leads at the top.
Screenshot_2020-02-21-04-41-04-1-1.png
 

ssjenkins

Feb 20, 2020
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Many thanks for that Tha fios agaibh . The only issue is that they look to be more expensive than the original RC oem part . I'll see if I can dig some up .

Sammy
 

ssjenkins

Feb 20, 2020
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Hi Guys .

I can get 100 X new 0.033uF axial 250V X2 caps for a decent price . Mine are 0.1uF though . Will it make much difference , or will I be able to get away with it ?

Thanks in advance

Sammy
 

bertus

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Nov 8, 2019
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Hello,

The circuit will be likely less effective with the 0.033 uF in stead of the 0.1 uF.
They will have a reason why they use the 0.1 uF.

Bertus
 

ssjenkins

Feb 20, 2020
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Hi Bertus !

Thanks for the reply . OK . I'll keep searching then :)

Thanks
 

bertus

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Nov 8, 2019
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Hello,

The RC combination is likely to be a snubber circuit.
The wiki has some info about the snubber circuits:
https://en.wikipedia.org/wiki/Snubber

I have also attached a PDF with some theory on snubber circuits.

bertus
 

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