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Replacing the mains filter capacitor

A

Atomtan

Member
Joined
Feb 9, 2011
Messages
34
Location
Leicester, UK
I need to replace this component on my 4016 (owned from new) as it keeps tripping the house power supply.

Having searched this forum, and the web, I find a lot of discussion about this item, but cannot track down a complete 'solution' as this component appears to be a mix of capacitors and chokes which I believe is long since obsolete. I have read that you can in fact leave this component out of the machine entirely but I definitely do not want to do this.

Would it be possible to replace it (albeit with some re-wiring) with one of the IEC mains input EMC/RFI filter sockets which are commercially available? I know this would have a kettle lead socket built into it, but wondered if this was a potential solution. Forgive me if it is stupid suggestion.

I also cannot read the specs on the current mains filter capacitor in my machine, and wondered if anyone could let me know what they are.

Many thanks for reading.
 
I would think there should be no problem with replacing the input filter with one of the many that are commercially available. You don't say where you are, but since you used the word 'mains', you're probably not in the US. Here in the US, I use Jameco Electronics for things like that, and they have a large selection.

I'm fairly certain that is your problem, because like you, I've read that it's a very common failure on the PET. Must be tantalum caps in there.

Atomtan said:
I need to replace this component on my 4016 (owned from new) as it keeps tripping the house power supply.

Having searched this forum, and the web, I find a lot of discussion about this item, but cannot track down a complete 'solution' as this component appears to be a mix of capacitors and chokes which I believe is long since obsolete. I have read that you can in fact leave this component out of the machine entirely but I definitely do not want to do this.

Would it be possible to replace it (albeit with some re-wiring) with one of the IEC mains input EMC/RFI filter sockets which are commercially available? I know this would have a kettle lead socket built into it, but wondered if this was a potential solution. Forgive me if it is stupid suggestion.

I also cannot read the specs on the current mains filter capacitor in my machine, and wondered if anyone could let me know what they are.

Many thanks for reading.
Click to expand...
 
The original will be obsolete...

Replacing it with a modern IEC unit will be fine. You can also purchase units that bolt onto a bracket and can be wired if that is of any help (it may help to keep the original external look-and-feel). You can 'gut' the faulty filter but keep the chassis-mounting socket. I can give you a website to have a look at if you let me know where you are (just so we get the right voltage)...

Dave
 
MainsFilterCapacitor_NOW_zpsd0140035.jpg


I assume that this is the mains filter capacitor and the goo coming from it shows its final demise is looming. I also notice that is has 2 x blue and 2 x black wires emerging from it.

Can I replace it with a unit such as those shown here?

http://i1349.photobucket.com/albums/p757/atomtan1/MainsFilterCapacitor_zps93bc87ba.jpg

One is for a washing machine, the other seems to be a commercial board mounted option. I have studies the schematics for the 4016 but an not sure how this component is wired. Any guidance would be gratefully received.
 
Thank you for the advice, I got one of these shipped from digikey as the dimensions looked good.

I stripped out the pets filter (the end cap is almost pushed out) and traced the wires back. One blue goes to power in live and the other to neutral at the power cable connector. The filter on the pet has its line earth on its casing as it attaches to the power supply.

I am a little worried about wiring the load side correctly. On the old pet filter one black wire goes straight to the transformer and the second goes to the on / off switch become coming back to the transformer. Can anyone suggest which way around the brown and blue load side of the new filter should be wired.
 
I thought I would add a few images of extracting the filter and how bad the original was.

So, I have attached an image of the machine before the old one was extracted, I got this machine new in 1982, so its pretty close to my heart.

The second image shows the filter after lifting the transformer away, what appears to be a large piece of candle wax is what had leaked from the cap and the third image shows the old filter, with its cap 'almost cooked off' by its impending demise, the replacement I want to install and the lump of gunk the old cap had shed.

If anyone can offer any advice on wiring the load side correctly of the new filter. On the old pet filter, one black wire goes straight to the transformer and the second goes to the on / off switch before coming back to the transformer. Can anyone suggest which way around the brown and blue load side of the new filter should be wired?

I have studied the schematics of the 4016 on line but they seem to show a more modern kettle lead filter connection.

CBM1_zps8c44b1ee.jpg


http://i1349.photobucket.com/albums/p757/atomtan1/CBM2_zpsd86a789d.jpg

http://i1349.photobucket.com/albums/p757/atomtan1/CBM3_zps13bd35be.jpg
 
Sorry - I pulled the information for you and forgot to post it (my bad).

In 'commodore colours' the two blue wires are "AC in" and the two black wires are "AC out". It would appear as though they did not differentiate (from colour at least) which one was live/line and which one was neutral.

Since you have a 'UK version' - brown is live/line and blue is neutral. Green/yellow stripe is protective earth (as usual). These colour codings should follow the standard for UK mains wiring.

I would wire the brown output to the switch/fuse and the blue output to the transformer.

However, what colours are the 'input' wires? I assume you also have a brown and blue on the input side of the filter also? If so, you need to make sure that the input brown side is actually wired to the live (fused) side of the plug-top with the blue wired to the neutral side of the plug-top.

The logic with this wiring is that if you switch the PET off at the switch (or the fuse blows) - this will kill the live feed to the transformer and all should be safe. If it is wired the other way round, then when the pet is turned off (or the fuse blows) then the transformer will still be live - as the switch/fuse is in the neutral side rather than the live side.

If this is not clear - please shout and I will try and explain a bit better (or locate a friendly, qualified electrician).

Dave
 
Finally found some time to finish this. I was a little worried as I did not strip down the entire power supply part of the machine (choosing to move it to one side), but one of the two cables on the high voltage side of the transformer snapped off.

I then had re-locate the new capacitor as space under the transformer is tight. (Please forgive the wiring, it has now been tidied up since the photo).

I checked the output voltages at the transformer outputs when everything was done (but before re-connecting the power supply to the main board) but they were higher than shown on this forum and that worried me for a while. In the end, I threw caution to the wind and it fired up first time as seen at the moment of switch on. I soak tested it for 3 hours, and no problems.

Many thanks for giving me the confidence to get this done and return an old friend to full life.

PET15a_zpsguhtfuv6.jpg



http://i1349.photobucket.com/albums/p757/atomtan1/PET15b_zpsfopjxt64.jpg
 
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