piakpiakbanana

Hello, help pls! I am looking for the datasheet for my ice shaver IS200 which recently got broken down.

History:
The blender stopped working yesterday i brought it to a technician to fix it. It seems that the fuse have broken and so he reconnected the fuse (not replacing it but by soldering an extra wire connecting the 2 poles). When he switched it on, the ice shaver started giving out smoke and i can smell some plastic burning kind of smell. The technician said he can't fix it and returned the ice shaver to me. When i got home, i took everything apart and i saw a severely burnt resistor. I tried measuring the burnt resistor (using this method http://www.technotronic-dimensions.c...Resistors.html) with my multimeter and i sum up to a total of 1k ohm. I replaced the burnt carbon film resistor with a metal film 1k resistor, and also replaced the fuse. When i switched it on, nothing happened. But when i flicked the switch to activate the ice shaver, the resistor started smoking!! I stopped immediately and unplugged it.

What should i do now?

Nigel Goodwin

Throw it away and buy a new one, it's probably the motor that has failed, with shorted turns internally.

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piakpiakbanana

oh i see, so its the motor thats causing the short circuit... i'll throw it away then..

thx for the prompt reply

Nigel Goodwin

Without seeing it, it's hard to be certain, but it's the most likely cause - and the engineer wouldn't have condemned it for anything trivial.

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David James

Given that (if I'm reading him correctly) the OP said the "engineer" attempted to repair the appliance not by replacing the fuse but by soldering a wire in place of the fuse, do you think "engineer" is an appropriate word?

Hero999

Measuring a burnt resistor won't always give its value before the resistor was burnt, it could have been a 100R before it was damaged.

The value of components can change when they fail: a burnt resistor will probably read a higher value than a non-burnt resistor, an inductor with a shorted turn will have a lower inductance and lower Q, a bad capacitor will have a lower capacitance and higher ESR.

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Nigel Goodwin

Without knowing exactly what it was, it's hard to say - but I suspect it was some kind of fuse type device - for testing purposes (NOT for returning to the customer) it makes sense to short it out, so you can test if it had failed for no reason. If it had failed for no reason, you then replace it with the correct safety component - but doing so before you test it, just blows the safety component again (which may be fairly expensive).

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piakpiakbanana

this is what i meant :



sorry for the small image, it might be hard to appreciate the diagram ~_~



Hero999: Is there any special method to measure the resistance of a burnt resistor? Sorry because i don't know much about electronics =/

Question to all = How would i know if a capacitor is working? Is it possible to test with a multimeter?


Thx for the education guys ^^

Nigel Goodwin

You can't measure a burnt resistor, you've no way of knowing if it's value has changed or not.

Only in a very limited sense, and only for a fairly small range usually - although some multimeters have a capacitance measuring range, but it only measures the capacitance, it doesn't really test it.

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Ubergeek63

That sounds more like a sleazy technician trick. An engineer might do that just to see if the motor still ran or to try and locate a short (by letting it overheat and "sniffing" it out), but it does not sound complicated enough to warrant that technique.

piakpiakbanana

Hello Nigel, may i ask how do i detect a faulty capacitor in a circuit board? I don't think my multimeter can measure capacitance =/

Nigel Goodwin

Generally you don't, although you can check many electrolytics in circuit using an ESR meter.

Fault finding anything is mainly a matter of understanding how it works, from there you can (hopefully) work out what part of a circuit might cause it behave in the way it is. Randomly checking components is pretty well doomed to failure.

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