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Parts Identification for dimmer

I have a light (incandecent) dimmer that stopped dimming recently. eg. It will turn the lights on and off but not dim.

I have identified the rather few parts in it pretty much. Capacitor

0.1K 250.Y.X , Triac Q202SK6, two resistors, one glass diode, Serious Dounut Coil, and one final part that I cant tell what it is. ".047K250" . Note the decimal. Is this a Diac? Its black rectangle with two electrodes coming out from bottom. I want to test each part to see what is broken to get it back on line.

Thanks

Reply to
steve
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That glass diode may be a diac, a device that switches on, in either direction, when the voltage across it exceeds something like 35 volts, to produce the gate pulses.

Sounds, to me, like a .047 uF (10%) 250 volt (possibly AC rated) capacitor. See:

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Almost certainly the triac. They usually fail shorted. Most units include a mechanical contact switch in series to turn it off. Sounds like yours is operating with only the switch.

Reply to
John Popelish

I agree with John. The component you question is most likely the cap described. Most likely failure, the triac. But check the diac also. Make sure the triac heat sink is fastened tightly if you replace it.

FWIW: I would just buy a new dimmer. It will cost you about the same as a triac and postage.

Tom

Reply to
Tom Biasi

The other parts you've gotten. The triac is a Teccor Q2025K6, not Q202SK6. It's a 25 amp, 200V triac with isolated tab. Replacement parts are available from many sources. If you're going to cross it to another part, make sure it has an isolated tab. And order a Q4025K6 if you can -- 200V is kind of cheaping it out for 120VAC.

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Check the triac first if nothing looks bad. And as mentioned in another post, make sure the triac is affixed well to the heat sink. Use tehrmally conductive grease if possible.

Good luck Chris

Reply to
Chris

it's a cap . 047 Uf, 250 working volts.

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Reply to
Jamie

I was thinking the same thing about buying a new dimmer. At the very least, it is local and available, while if you don't have the parts on hand it will take time and at the very least shipping to get the devices. There isn't much in those things beyond the triac and diac.

Indeed, I kind of wanted to do something with some triacs, and I've been thinking about buying some light dimmers for the parts, simply because they are handy.

Michael

Reply to
Michael Black

Thanks all for your responses. I had forgoten what a diac looks like, despite the fact that I think I have used them before in phone projects. The cap as you have identified, fooled me because it did not look like your average capacitor. I suppose because its a heavy duty one. Im not use to working with them.

Thanks

cm

Reply to
steve

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