RE: [OT] Dimmable lamp troubleshooting

["Keith Doxey" <ukha@xxxxxxx>]

Hi Steve,

almost certainly the triac.... and there is some automation...

cheap dimmers automatically protect the fuse by allowing the triac to blow
first :-(

Good quality Ultra Fast HRC Ceramic fuses do a good job of protecting
triacs
but often cost 3 or 4 times as much as the triac !!!

I had a disco controller that had 8amp triacs and 2 amp fuses mounted
internally. I fitted external fuseholders for the 2A fuses and fitted 5A
fuses to the internal fuseholders. almost everytime I blew a lamp I would
loose the triac and the 2A fuse, sometimes also the 5A fuse, because the
"Quick Blow" fuses costing 10p each were not fast enough. Quite
often the
glass fuse body would shatter as well.

After replacing all the triacs with 16A devices and using Ultra Fast 2A HRC
fuses externally but keeping the Quickblow 5A internally I never lost a
triac again.

I once had a faulty lead amongst the 15 or so leads connecting the light
boxes together and blew about 10 fuses before I eliminated it but the triac
survived perfectly. Sadly I later lost the whole controller when someone
broke into my van and nicked my Amp Rack :-(

Keith

www.diyha.co.uk
www.kat5.tv


> -----Original Message-----
> From: Steve Morgan [mailto:steve@xxxxxxx]
> Sent: 05 August 2003 22:14
> To: ukha_d@xxxxxxx
> Subject: [ukha_d] [OT] Dimmable lamp troubleshooting
>
>
> No automation involved here, so it's off-topic, but this is definitely
> THE place to ask......
>
> I have a brass bedside lamp that has a three-step touch dimming
> function. A while ago the bulb blew. I replaced the bulb and now I can
> neither dim it nor turn it off. My assumption is that the triac (a
> BT136) has shorted. Is this the most likely thing, in which case I'll
> replace the triac, or do I have to actually investigate the problem
> properly?
>
> Cheers,
> Steve
>
>
> [Non-text portions of this message have been removed]
>
>
> ------------------------ Yahoo! Groups Sponsor
> ---------------------~-->
> Buy Ink Cartridges or Refill Kits for Your HP, Epson, Canon or Lexmark
> Printer at Myinks.com. Free s/h on orders $50 or more to the
> US & Canada. http://www.c1tracking.com/l.asp?cid=5511
> http://us.click.yahoo.com/sO0ANB/LIdGAA/ySSFAA/IBOolB/TM
> --------------------------------------------------------------
> -------~->
>
> ** UKHA2004 BE THERE! ** - start planning now.
>
> http://www.automatedhome.co.uk
> Post message: ukha_d@xxxxxxx
> Subscribe:  ukha_d-subscribe@xxxxxxx
> Unsubscribe:  ukha_d-unsubscribe@xxxxxxx
> List owner:  ukha_d-owner@xxxxxxx
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>