Touch dimmer lamp breaks when bulb fails

Mar 06, 2017 8 Replies

I bought a couple of desk lamps with touch setting for 3 levels of brightness. One lamp got knocked over causing the bulb and fuse to both blow. I replaced the fuse and bulb but the lamp doesn't work.



Then the same happened to the other lamp.



Inside there's a block marked "Hopestar LD 600 touch dimmer". Is it normal for the touch dimmer unit to blow like this?



we certainly have one blown one here. Another trip to JL only to discover that we have a discontinued model. So we had to buy 2 to get a matched pair

- we use them as bedside lamps.

One bulb was a halogen and the other an old style tungsten bulb.

Surely the dimmer is too fragile to be fit for use in a lamp if it's likely to blow when a bulb short circuits?

Although I call them desk lamps, these were also used as bedside lamps. The design seems very fragile.

Do I have a reasonable case for a refund? I don't have the receipts unfortunately and the lamps are about 9 to 12 months old.

Our floor standing reading lights have touch dimmers. My wife's has gone insane since the bulb blew and busily cycles round all by itself.

Can you get the dimmers?

Even traditional filament lamps will sometimes short circuit when the filament breaks, causing the MCB to trip. Less likely if the bulb has an integral fuse in the base, but many haven't these days. AIUI as the filament breaks, the arc that forms momentarily between the two ends of the broken filament vaporises enough tungsten to provide a highly conducting path between the wires supporting the filament, in effect causing a short circuit.

I imagine that the chip in the lamp that regulates the current in the lamp itself just can't cope.

It's not uncommon - repaired some at repair parties. Owners have obtained replacements from ebay via China. The last one I helped with a couple of months ago, the guy had ordered two different ones (I think they were under 2 quid each). It was a good job he did, as I refused to use the one which didn't have a Class Y capacitor on the connection to the lamp body, and you simply can't tell that sort of thing until you have it in your hands.

Such a type of short circuit might reasonably be expected to occur. Perhaps not every time but, say, half of the times a bulb blows.

It seems a bit unreasonable to sell a lamp that will no longer work after a few bulb failures.

The wretched lamp only takes halogen or tungsten bulbs, so it's not as if I could have used anything else.

I'd say no, but it depends on how the bulb fails. I don't think many dimmers like a very hard short for more than a split second. I once bought a job lot of 100w bulbs from a corner shop, branded Tesla. Every one of those blew short, dead short took out three dimmers and popped breakers, so after the replacement of the triacs in all the dimmers, relegated the bulbs to the shed instead.

Brian

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