Burnt out mains capacitor

Hi there. This looks like a great newsgroup.

Husqvarna Optima 150

We have burnt out an AC capacitor in our old Husqvarna. What we wanted to know is if it's alright to continue using it with the cap removed, at least till we can find another one?

Is it just a RF suppressor, or is it to st Front: RIFA

40/085/56 GPC PME 271M 610 CP9

Top:

0,1uF@X

Back: fo=4,9MHz 250V~MP

565-1ALD2

There are some other symbols on the back that despite looking up special symbols tables, I found no way of reproducing. But I think there is more than enough information there anyway. (:

We couldn't find much in the way of caps in Australia so would one of these do the trick? The direct link to the page is way too long, so I had to use tinyURL to create a link, sorry.

This is the home page, just in case your wondering.

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is the tinyURL link to the high voltage capacitor page.http://tinyurl.com/l2bh4nAny help with this will be greatly appreciated. Cheers.

-Chrisy

Reply to
Chrisy
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I'd say probably not. This machine has electronic speed control, and this component could easily be part of the control circuit, not just a transient supressor.

Having refurbished components on an Elna TSP Air Electronic circuit board (which required me to reverse-engineer the circuit diagram), I would say that it's not safe to assume that this capacitor is just a mains supressor

I can translate some of these

Manufacturer, Evox Rifa

40/085/56 - IEC Climatic category: 40°C, 85% rH, 56 days

Manufacturers item code

0.1 microFarads, the capacitance of the device. X - Classification of capacitor,international standard. Intended for use as interference suppressors across the power input. That doesn't mean that it can't be used for something else, of course.

fo=4,9MHz - self-resonance frequency 4.9MHz

250V - 250 volt rated voltage MP - Metallised Paper, the construction materials

These are likely to be the various standards markings indicating certifications and approvals the device complies with.

The capacitor should look a lot like this one:

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Your tinyurl isn't working for me. From the supplier you've chosen, I'd go for this component, which will replace your burned-out example

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Reply to
Alan Dicey

It is.

On a note related to your machine, do you have the owner's manual? If not, I can copy mine for you...

Reply to
Kate XXXXXX

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Thank you so much Alan for the link and the great advice. Imagine how much the shop would have charged us to replace one cap. Probably about $70AU (approx £35) would be a fair guess.

Dick Smith want $0.95 for the cap plus $9.95 for P&H, so you've saved us around $60! You've really helped us out a lot.

I never realised how many amazing things capacitors are used for till I started to look into it yesterday. You must really know your electronics. It was the use of a comer instead of a full stop as a point symbol (0,1uF) that confused me. I didn't know if it meant 0.1 or

1 uF, but I guess 1 Farad must be quite a lot. Some of those larger caps sound quite dangerous.

The tinyurl link didn't work here either. I had to find and install the add-on and now I don't know why I bothered. Maybe tinyurl.com is a blocked site in my hosts file.

Anyway, cheers for that Alan, it's very much appreciated.

And being and Aussie Sheila I guess I better say it just for a laugh. Your know you want me to! "Where the bloody hell are ya!?"

-Chrisy

Reply to
Chrisy

Hi Kate. Thanks so much for the offer. No I don't have the owners manual. I sort of inherited the Husqie from my mum a few years ago, and I've never even seen the manual.

If it's not too much trouble, it would be very kind of you to copy it. Do you have a scanner? At least that way it wouldn't cost anything to send all the way to Australia. From your header, it looks like both you and Alan are in the UK.

Cheers for the offer Kate, you really are a sweetie.

-Chrisy

Reply to
Chrisy

Yup, same house on top of the North Downs, working feet apart!

No bother. I try to scan all my manuals so that if they go missing or I destroy them with a Biblical Flood of tea, I'm not totally sunk! If I haven't yet done this one, I will today, in between finishing off the customer's order! Dress to cut out and sew up (simple back and front: TWO LONG SEAMS AND BIAS BOUND EDGES - I know, cheating! ;) ), petticoat and Regency Pantalettes. Should all be done by this evening.

I got my 190 in a swap with my sister: she took the tiny Singer 117 Featherweight II I bought for my mum about 3 years ago, I got the 190, and mum gets free sewing for life! :D

Send me a working email if the one to the group is a false one. Reply To should work...

Reply to
Kate XXXXXX

The shop would charge for the labour involved in removing and replacing the circuit board and the component. Maybe 30 minutes to one hour.

The postage seems a lot compared with the component price. Maybe its worth skimming Dick Smith's catalog for anything else you might need - tools, solder, adhesives, CD/DVD-ROMs, cases, that sort of thing.

In the UK I am lucky that there is a supplier that maintains a physical presence, real shops you can visit. Maplin Electronics has two shops within a 30-mile radius of here. Tandy/Radio Shack used to have a shop even closer, but they have closed down in the UK - however they still appear to be alive in Australia, so it may just be possible there is one close to you. Whether it is within AU$10.00 worth of petrol is a separate question :-)

In Australia I expect that distances between towns are larger and useful shops less widely distributed. I can find other online suppliers, though, Jaycar, Altronics, Farnell Australia and RS Components Australia, should you need to shop around in the future.

The use of a comma for the decimal place is standard practice in continental Europe. Rifa is Swiss-based.

Capacitors are charge storage devices, and large devices can store enough to give a startling shock. One Farad would be a large capacitance, and I've never seen a single device that large. In the few applications where they are necessary they are built up from banks of smaller devices.

The biggest danger from larger capacitors is explosive decomposition from putting AC across them. Larger capacitors are polarised and can only be connected across a load where the DC component is larger than the AC ripple. Going negative will result in a fountain of hot paste spitting out of a safety vent in the lid of the can.

Anything can be dangerous if handled carelessly.

No problem. I assume that you or someone nearby is confident enough with a soldering iron to swap out the dead component.

I'd be careful to check the machine for any other damaged components, resistors showing signs of overheating or capacitors with bulged cases. When I refurbished Kate's Elna, the root of the problem was a burned-out resistor, the capacitors had just aged and bulged from overheating. Metallised Paper capacitors are known to deteriorate with age. It may be worth replacing any other such devices on the board.

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not to overheat the board while soldering or desoldering, especially if close to any active devices (transistors, integrated circuits - generally anything with three or more leads). Also, the printed circuit tracks can lift off the surface if overheated. A desoldering pump can be helpful.

Out of interest, can you post pics of the board, showing the burned out component, if you have a digital camera?

The UK. Same house as Kate :-)

Reply to
Alan Dicey

Ah yes, the yellow stinky stuff. ;-) DH not me - it stains too, much like ferric chloride.

Lizzy

Reply to
Lizzy Taylor

The most likely electrolyte is apparently boric acid or sodium borate. There'll be a lot of fried paper in there too, and whatever other additional solvents or modifiers are needed.

Reply to
Alan Dicey

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Hi Alan. The closest shop that sells that sort of thing is in Cairns, around 3 hours drive from where we live. So $10 is much cheaper (and safer) than driving that far. Our local sowing shop sends all machines that need work down to some place in Cairns, so we wouldn't see it for a fortnight if we took that route. Where as the cap should be here is 3 to 4 days.

The cap isn't on a circuit board, it's across the 240v power supply/foot pedal socket just inside the case. It doesn't seam to have a PCB at all. Unless there is one in the foot pedal. The rocker switch for the light seams a little 2nd. hand though. But whether it would be possible to find one that would fit our machine is another story.

My partner of 12 years, besides being a lazy sod lol, is fairly handy all round. He built this house (not quite finished yet), built our desk top computer, and replaced 2 blue caps in it's LCD monitor a few months ago, when it refused to come off stand-by. He said to say that he just hasn't had much to do with AC caps before. And despite his (mounting) collection of old PCBs' (aka junk), had nothing like the one in our sowing machine. The example cap in the link you posted looks very similar, if not identical to our dead one though. A rectangular transparent beige box, with two wires and lots of numbers, with no "-" mark for polarity.

Just out of interest, here is an interesting link which mentions 5,000F caps.

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saw a large blue cap in a guitar amp blow once. Quite a loud pop,some sparks and lots of white smoke. It was very funny, but ourguitarist didn't think so at the time. (: Lots of paper and foil hangingout the back of his amp, lol, those were the days! When the cap in theHusqie went, it was no where near as exciting. Just a quiet pop and somewhite smoke.

Thanks again Alan.

-Chrisy

Reply to
Chrisy

Ok, thanks again Kate. I just sent you an email with one of our working email addresses.

That sounds like a good swap to me. A real win/win situation.

I'm not that good at sowing myself. My partner, Adrian, is actually better at it than I am, /blushes, but less motivated. So I guess that sort of balances us out. (:

Your web site looks great, and very useful, I think you will be getting a little more traffic for a while at least.

-Chrisy

Reply to
Chrisy

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Hay Alan. The cap arrived today, Adrian put it in, and it works like a charm! Thank you so very much for your able assistance.

Maybe it's just a cheaper version, but the new one is a fair bit smaller, then again I guess 20 odd years is a long time in electronics.

I took a few pics (as you asked) with my mobile, and as soon as I fire up my work laptop with the bluetooth card in, I will email them to you. Yours gratefully. Chrisy.

Reply to
Chrisy

Chrisy - from your previous description, that the capacitor was simply screwed into the power cord terminals with no other circuit board, I'm certain that it is just a mains supressor, and nothing more complicated. Kate's 190 does have a circuit board with a microprocessor on it (I've had a look), attached to the power cord plug., which would make it more of a risk to run without a component.

Reply to
Alan Dicey

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