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Who knows about electronics?


dave21478

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Does anyone have any knowledge of electronics on here?

I loaned my cordless impact wrench to a bunch of hippies. That was my first mistake.

"Yeah man, great, thanks, it was a big help.

Oh, the charger doesnt work anymore though."

Turns out that they had left it outside in the mud and rain for several days, if not weeks.

I took it to bits, drained the water and let it slowly dry out over several days near a radiator but still nothing. I then noticed this component is split.....

http://s8.postimage.org/hjyyxwc6d/P1000607.jpg

(You will have to copy and paste that link - I wont even try to post the image directly as I doubt anyone will have done anything about posts from Chrome not showing up properly)

three rows of lettering.

Top is " E" and a squiggly that might be a logo of some kind

middle is "103M"

Bottom is "1KV"

So, the question is - if I replace this component, is it likely to work, or will there perhaps be other faults that caused this part to fail? Try it and see, I guess?

I assume its a capacitor?

I found these on ebay....

http://www.ebay.co.uk/itm/20-x-CAPACITOR-CERAMIC-HIGH-VOLTAGE-10NF-103M-1KV-/130822003693?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item1e75995bed

which look likely, but he wont post to France. Does anyone know where else I could buy these? I can't find the right thing on the Conrad website, and I believe they have a minimum order of 15Euro anyway.

Any other suggestions of things to test/check? All the other components on the board look ok to my untrained eye, although one of the larger capacitors, about 2cm dia by 5cm long appears to have moved - Most of the components have had some kind of glue or resin poured over where they connect to the board and there are cracks around the base of this capacitor - I have no idea if it has failed causing it to expand or if the cracks have been caused by something else or even if they have always been there.

Thanks.

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That capacitor is (probably) directly across the mains input and although it has blown it's think I can safely say that it will not be the cause of the charger not working. Here is a representative circuit and it's C1.

[img]http://www.hqew.net/files/Images/Article/Circuit_Diagram/constant-voltage-smps-circuit.gif[/img]

The value of the capacitor is nominal and if you have something laying around with a switched mode PSU it will almost certainly have a similar capacitor which you could steal and fit if you wanted to but as I say I'm sure it will make no difference.

Unfortunately you cannot troubleshoot things like that by eye so there's no saying what's wrong without both the knowledge of how to test the components and the equipment to test them with.

Sorry.

You have of course checked the fuse - if one is fitted ?

EDIT: FWIW, the bigger electrolytic capacitors are common failure points in this type of power supply but the only real way to prove them is by replacement.

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Not necessarily so.

In UK I dropped a mobile phone down my pit which at the time has about 3" of water in it due to an inordinate amount of rain coupled with an already high natural water table in the first place.

My initial though was that it was done for and as it was an oldish one I didn't bother removing the pit boards to climb down and retrieve it but got on with what I was doing.

About half an hour or so later I happened to notice that the screen had come on so I did fish it out and saw it had a message on the screen saying 'Insert SIM' and I figured that if it was still working to the extent of giving a coherent messge like that then perhaps all was not lost so I put it on a radiator to dry out and a couple of hours later it was working again.

My wife is still using it here in France !

For the record it's a Sony Ericsson T630.

[img]http://www.extragsm.com/images/phone/big/Sony%20Ericsson/T630/Sony-Ericsson-T630-01.jpg[/img]

Also, way back in my late teens I was given a Perdio Town and Country radio which had been dropped in the sea and only retrieved at low tide some hours later - I got it working again. So no, water ingress is not an automatic FUBAR !

[img]http://www.thevalvepage.com/radios/perdio/pr41/perdio_pr41_front.jpg[/img]

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Thanks. I will try replacing it, but I have my doubts.

I'm kind of snookered without it though. Its a Snap On brand, and they don't sell replacements through shops or online as far as I know unless you live within USA. Buying from them involves face-to-face transactions with their reps who are franchise dealers who normally sell door to door to garages in their area. I will have to wait till I am next back in UK and track down a Snap On van.

There are a couple on ebay just now. They are rare on there, but there is one used mains one just been listed and a brand new one, but its powered by 12v for use in a vehicle. It would do at a push but I would prefer mains.

Bloody crusties! - Lesson well and truly learned there.
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What voltage is the drill?

You could buy a cheap charger for another make, not a cheap cheap Kinzo or Power Devil but a proper charger that has the 3rd terminal that I expect your Strap-on battery has or if not one that senses the thermal cut out in the battery, gut the internals and cobble them into your casing or if too large cut up your casing and make a Frankenstein, its the sort of thing that you excel at Dave [:D]

Editted, if its 12 or 14.4 volt you can use a car battery charger for the time being.

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[quote user="Chancer"] if its 12 or 14.4 volt you can use a car battery charger for the time being.[/quote]I was with Chancer up until that point.

Using a car battery charger for Nicad or L-ion batteries is a seriously BAD idea and could quite possibly destroy your power tool batteries !

The former is achieved by constant voltage and the latter constant current, two entirely different and incompatible processes.

L-ion can use use CV but in a highly controlled way which no lead acid battery charger can emulate.

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The Snap On is 18v.

I have a dose of other 18v chargers here, but was wary of trying to adapt one.

The Bosch drill takes NiMh batteries, its charger has 4 contacts on the charger.

The Dewalt drill takes NiCd batteries and it has 3 contacts,

The Makita driver takes NiMh batteries and has 5 contacts.

The dud one is also NiCd and 3 contacts, so the Dewalt looks the closest so I popped it apart but it is a very basic circuit indeed compared to the snap on charger.....better controls? Trickle charging? Who knows - electronics is pretty much voodoo to me and I am not willing to risk cooking the batteries as I need them all tip-top for work and they are not cheap to replace - especially the snap on ones. I don't rate their hand tools that highly - nice enough but very over priced IMO, but this driver is about the best cordless that money can buy and its something I use a lot, so I paid out a lot for it and am glad I did.

Technically, their stuff all has a lifetime guarantee, although crusty hippies leaving it in the rain is probably not covered.
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HSD - that auction is for an old USA model. They are reasonably plentiful on ebay USA, but USA chargers will only work on 110v, so no use here.

The driver is a CTU4850HO The charger is a CTCF620

Previous experience of dealing direct was a waste of time. Repairs need to be posted to them, assessed, repaired and returned - a process which takes months and costs a lot. To buy a new part, they just refer you to a local franchise, which means a trip back to UK.

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