Why my touch-lamp won’t turn off

I have a bedside lamp that does the cool off-low-medium-high cycle thing. Or did, that is. Recently, the bulb in my lamp burnt out, so I bought a replacement. When I put it in, though, it wouldn’t cycle. I could feel the faint fuzziness of the lamp registering my body’s capacitance, but the light was unmoved; it just stayed permanently on. Perplexed, I thought maybe I’d bought the wrong kind of bulb, so I bought some more. Same result. It seemed too much of a coincidence that it would stop working right when I needed a new bulb, but then I found this interesting tidbit, from a FAQ on touch lamp problems:

These are susceptible to damage from voltage surges or just plain old random failures. In addition, the current surge that often results at the instant an incandescent bulb burns out (the bright flash) may blow the thyristor in the electronics module. If the lamp is stuck on, the thyristor is probably shorted.

My thyristor is shorted!

So, what’s a thyristor? One definition:

  • A semiconductor used as a gate circuit. The solid state equivalent of a thyratron.

  • But what’s a thyratron? Wikipedia to the rescue:

    A thyratron is a type of gas filled tube used as a high energy electrical switch. Triode, Tetrode and Pentode variations of the thyratron have been manufactured in the past, though most are of the triode design. Gases used include mercury vapor, xenon, neon, and (in special high-voltage applications or applications requiring very short switching times) hydrogen.

    So a thyristor does the same thing, without the gases. What’s actually in a touch lamp is a triac, composed of two thyristors.

    But anyway, the unfortunate upshot is that the lamp is now non-touch-sensitive. Apparently I can buy a plugin touch-sensitive box to restore that functionality, or, of course, I could just buy a new lamp. And track its usage so I can estimate when the bulb is about to die and swap it before the cataclysmic “bright flash” kills that lamp, too. Maybe a lamp with a manual switch isn’t looking so bad now.

    Update (Feb. 13, 2011): I have successfully fixed the lamp! Thanks to Cakky_blue, below, who suggested exactly the right fix.

    86 Comments
    62 of 76 people learned something from this entry.

    1. Sylvia said,

      April 17, 2012 at 2:57 pm

      (Learned something new!)

      we thought ours went out because of the surge protector going out. replaced surge protector, light bulb was out in lamp, (very likely due to the surge protector failure). replaced bulb, it was “stuck’ on, here I am! thanks, will send a link to the mr.

    2. Tony Davis said,

      May 1, 2012 at 4:53 pm

      (Knew it already.)

      Hi, I am glad that all of you reading this blog, have got something from MY original article on fixing touch-lamps (I see that some posts have a link to my LAMPS page). It is rather weird that this blog gets a higher ranking in Google than my original article on this, going back to around 2005. I think the newer term for the controlling semi-conductor is a TRIAC, the term THYRISTOR is now going out of use, as they tended to control the current on one direction only, but a TRIAC is a BI-DIRECTIONAL device, ideally suited to A/C applications like dimming and power controllers. Those of you who are able to obtain the energy C rated lamps (e.g. candle lamps with G9 Tungsten capsules INSIDE the main candle envelope) should find that these types tend NOT to fail and draw a large plasma-arc current, as the high-pressure halogen/xenon mixture tends to prevent this, so should NOT destroy a TRIAC (unless you have used a lower current handling device, like a BT134). It is this high current during the few milliseconds when the filament parts, that will destroy the TRIAC – it has NOTHING to do with spikes and transients coming INTO the lamp – it is just the failure-mode of the bulb itself doing the damage! Hope this helps, Tony Davis, LETSFIXIT.CO.UK.

    3. Glenna said,

      August 28, 2012 at 6:47 am

      (Learned something new!)

      Fascinating stuff, but I don’t think I’m up for this repair. Maybe I’ll just head to buy another lamp…
      But thanks for all the great info!

    4. EDWARD said,

      September 15, 2012 at 1:26 pm

      MY LAMPS HAVE THE ADD ON TOUCH ADAPTORS AND ALL JUST STARTED WITH THIS FLICKERING PROBLEM. BY COINCIDENCE IT STARTED
      WHEN I BUNDLED WITH MY TIME WARNER PEOPLE. THEY DENY THAT THIS COULD BE CAUSED BY THE MODULE BOX THAT WAS INSTALLED TO CONTROL THE TV,PHONES AND INTERNET. ANY HELP OUT THERE?

    5. Fraser said,

      September 19, 2012 at 9:05 am

      (Learned something new!)

      The link everyone was using http://letsfixit.co.uk/html/lamps_faq.html is gone =(

    6. Kiri said,

      September 19, 2012 at 9:29 am

      Here is a snapshot from the Internet Archive:

      http://web.archive.org/web/20101126071038/http://letsfixit.co.uk/html/lamps_faq.html

    7. Mike said,

      October 1, 2012 at 6:01 am

      (Learned something new!)

      Might have to give this a go however I’m thinking of swapping my faulty touch lamp(same prob as everyone else) with my wife’s. Reason being my daughter just bought a new kitten with a very bloody cheeky personality. He is also very intelligent. Guess what? He worked out how to annoy us at 4:30
      am each morning when he is starting to feel a bit peckish. He jumps onto my wife’s bed side table and taps on the light with his paw!!! Fixing my lamp will mean less sleep, and swapping will thwart him for a while so give us back our mornings, but this will annoy my wife who likes her touch lamp cos she reads a lot.
      Any suggestions??????????!!

    8. Joy Lingerfelt said,

      November 29, 2012 at 12:37 pm

      (Knew it already.)

      My bulbs havn’t blown on my tap lamp , just can’t get this to work in MOST of the outlets in my home. Works fine in wall outlet in the garage. All outlets work for other appliances, lamps, etc. But these lamps wont work in outlet in B/Room, or Kitchen, or Living room…
      WHAT do I change for that? (It really does it’s thing correctly in some of my homes’ outlets, and at my office.)

    9. MaltIsGood said,

      February 8, 2013 at 9:48 pm

      (Learned something new!)

      You are awesome. Thank you for that information,

    10. Wender said,

      April 12, 2013 at 7:16 pm

      (Knew it already.)

      Same as the lady before me. Will work sometimes if i hold onto something metal.
      My bulbs havn’t blown on my tap lamp , just can’t get this to work in MOST of the outlets in my home. Works fine in wall outlet in the garage. All outlets work for other appliances, lamps, etc. But these lamps wont work in outlet in B/Room, or Kitchen, or Living room…
      WHAT do I change for that? (It really does it’s thing correctly in some of my homes’ outlets, and at my office.)

    11. Sarah said,

      May 14, 2013 at 8:17 pm

      (Learned something new!)

      thank you i was having the same problem and this explained everything! i found a repair part on ebay for $7.50 with free shipping, you can probably find similar ones also.

      http://www.ebay.com/itm/TOUCH-LAMP-SENSOR-REPLACEMENT-100-WATT-120-VOLT-TOUCHLAMP-REBUILD-REPAIR-/350728361370?pt=Lamps_US&hash=item51a90a159a

    12. Marci said,

      September 30, 2013 at 7:37 pm

      (Learned something new!)

      This is the second touch-lamp that has blown on me in about 15 years. After reading this, makes me miss my Dad even more. Before he passed, he loved using solder and soldering iron, troubleshooting and fixing electronic things. He could’ve easily fixed it in a matter of minutes just tinkering on Saturday afternoon…

    13. Steve said,

      October 7, 2013 at 11:15 pm

      (Learned something new!)

      I really enjoyed reading all these, but I am asking now why is my problem different to everybody else’s? My bulb was blown and after replacing everything worked fine for about two years when it started going off and doesn’t remain on after a minute or so…. I bought another more expensive lamp – not knowing about a possible repair – and since I don’t own a solder I don’t want to replace the TRIAC but would be happy to buy a switch for it. Would it be safe to bridge the chords around the TRIAC?

    14. Kevin Shaw said,

      April 24, 2014 at 6:33 am

      (Learned something new!)

      I can answer a few of your questions. Touch lamps are highly susceptible to power surges. Also if a touch lamp gets knocked over many times it will blow the sensor. Our experience is that when replacing the sensor make sure to match the watch of the older sensor. OK Lighting is the largest seller of touch lamps in the U.S. They use a 100 watt sensor. There are 120 watt sensors and 150 watt sensors out there. If using a OK Lighting sensor in a lamp that had a 150 watt sensor the problem is it is wired differently by that manufacturer. In an OK Lighting lamp the white wire from the sensor attaches to the black wires from the base. The red wire would then attach to the white wires from the lamp and one of the wires from the cord. But other manufactures reverse this and if hooked up wrong the sensor blows immediately. The wattage of a sensor is on the plastic casing of the sensor. You may need a bright light or magnifying glass to read it. Hope this helps.

    15. Oliver said,

      September 23, 2014 at 2:02 am

      (Learned something new!)

      Hi All,

      I have found the guide again on the lets fix it website – http://letsfixit.co.uk/989/how-do-i-fix-a-touch-lamp/ also found http://letsfixit.co.uk/lamps-faq/

    16. Claire said,

      October 7, 2014 at 2:13 am

      (Learned something new!)

      OMG I’m crying with laughter…!! Never been so entertained trying to find out a wee bit of info… Thank you EVERYONE who has posted snippets xxx yeah my lamp is stuck on… Yeah, there’s no way I’m pulling it apart.. Yeah, gonna keep plugging it it manually when I need it LOL !!!! Xxxxx

    17. Steve said,

      March 6, 2015 at 4:12 am

      (Learned something new!)

      I have those screw in adapters. Worked great for a long time, but then the light started coming on all by itself…very annoying. Replaced the adapter, and eventually the same thing started happening. I guess that’s why it is rather hard to find those adapters anymore.

    18. nancy said,

      April 11, 2015 at 3:49 am

      (Learned something new!)

      Is there any other way to turn on a 3-way lamp other than with human touch?

    19. Catherine said,

      June 7, 2015 at 1:29 pm

      (Learned something new!)

      Thanks for the info – just what I was looking for. My touch lamp bulb (40W chandelier bulb) blew today after at LEAST 14 years!!! Bought replacement bulbs and no luck – it just stays on. I’m devastated (really I AM!!) but I’m going to switch to a manual switch lamp. It’s too much trouble to fuss with the touch lamp which was really cheap in the first place anyway.

    20. Liz said,

      July 18, 2015 at 7:08 pm

      (Learned something new!)

      bought a new table lamp at Target today. tag on it said includes 60 w CFL which it didn’t but I have those. Brought it home, put in bulb, found out it’s a touch lamp. within an hour would not turn off. googled the SKU and it’s apparently a lamp sold in 2003 at a place no longer in business. Someone must have pulled a fast one on Target by switching out the tag. so now the brand new (to me) lamp can’t be turned off cuz I wrecked the sensor with the CFL. I guess I will take it apart one of these days and rewire with a switch because it’s really a beautiful little lamp. Brushed nickel base with a fitted cobalt glass cylinder shade.

    21. Brian Otieno said,

      April 20, 2016 at 10:48 pm

      (Learned something new!)

      Connecting the two of the three wires of the sensor with an extra wire did it for me. The sensor has three legs going into the board. Link two with a wire and you are done though the touch property will be a story.

    22. ROY WIGGINS said,

      May 2, 2016 at 4:18 am

      (Knew it already.)

      iI’s a bit late for me to see this but you may like to buy another set of electronics for your touch lamp – see item
      No.331844575658 in EBAY. for details. price is only 6.5gbp.
      ROY

    23. R. Allen said,

      May 5, 2016 at 1:33 am

      (Knew it already.)

      I have a brand new Tommy Bahama China Cabinet. Its touch light, activated by touching the hinge, has not worked properly from day one. Within minutes of being turned on, it starts to cycle through the 3-intensity settings, and then off. Sometimes will stay off for a while, and then turns itself back on. Sometimes it will just stay off once it turns itself off. Furniture store actually replaced the entire cabinet. Touch switch that came with new cabinet behaves exactly the same. Store technician came out and said there’s an issue with our outlet. I’ve used an extension cord on outlets on different breaker. House is less than three years old, and is considered a high end house and has no electrical issues. Suggestions besides just getting rid of the touch lighting (which I may do) or getting rid of the cabinet (which we like very much)?

    24. Jack Clark said,

      May 20, 2016 at 7:00 pm

      (Knew it already.)

      Simple. I bought a little inline switch for $3.50. pulled the plug so no live juice.

      cut one wire 6″ from the lamp. Installed the switch and voila, I have a wonderful

      little switched lamp. Takes any regular bulb. You don’t need to be an electrician

      to do this.

    25. Virginia B Yocham said,

      October 24, 2016 at 4:42 am

      (Knew it already.)

      Just an fyi- they also make a touch light socket that turns any lamp I to a toch lamp. Much handier than a new lamp or dimmer boxes

    26. Virginia B Yocham said,

      October 24, 2016 at 4:44 am

      (Knew it already.)

      Just an fyi- they also make a touch light socket that turns any lamp I to a touch lamp. Much handier than a new lamp or dimmer boxes

    27. Virginia B Yocham said,

      October 24, 2016 at 4:47 am

      (Learned something new!)

      Sorry– hit post twice

    28. Patti Allen said,

      October 30, 2016 at 6:33 pm

      (Learned something new!)

      I think this may be similar but I did not see any one ask about a touch bar on the back a nightstand to turn light on and off. Same thing happened. Falsh of light and bulb went out. Replaced bulb, Touch sensor on back of nightstand wont work .. Any experts out there to help with this. WE love the touch sensor for turning lights on and off from the bed.

    29. Tish said,

      December 25, 2016 at 10:24 pm

      (Learned something new!)

      I have 4 small can lights on the bridge above my bed and loved the convenience of tapping a copper bar for reading or whatever….. When I was replacing one of the bulbs, the base of the bulb did not twist out with the bulb and I created
      (I think) a surge when the filament popped… hasn’t worked since and I’m DETERMINED to fix it, no matter what! Any links to the correct sensor or company supplying these parts would be greatly appreciated!

    30. Wood Sunglasses Guy said,

      January 17, 2017 at 3:24 pm

      (Learned something new!)

      Awesome! I have a $12 touch lamp from Walmart and I went through the exact thought process of “Why would the touch functionality stop working at the exact same time as the bulb burning out? I thought it was the bulb too.

      While I don’t like the prognosis, you saved me a ton of time trying to fix it. Thanks a ton!

    31. Jan said,

      February 1, 2017 at 10:28 am

      (Knew it already.)

      I know the parts can be replaced, however everyone continues to mention amps and all kinds of numbers that make no sense to me. How about a normal answer to make it simple? My lamps were purchased at an old farmers market in the U.S.

      I have three of these lamps that all have the same issue. I guess I can sacrifice one to experimentation since I have no electrical knowledge. I just need to find the correct parts to keep as a touch lamp.

      Then again, if someone could provide detailed info on how to change them to a normal switch, that could also be helpful too.

      Thank you!

    32. MikeN said,

      February 5, 2017 at 5:55 pm

      (Knew it already.)

      If you use Powerline adaptors for your Internet they will cause touch lamps to turn on and off randomly also

    33. Rarly said,

      June 19, 2017 at 2:31 pm

      (Learned something new!)

      You could get an led for the lamps so that you don’t need to worry about the burning out.

    34. jimsam said,

      June 28, 2017 at 11:44 pm

      (Learned something new!)

      ok. my bulb blew and the new one stays on. is it ok to leave it on?
      otherwise it is going in the deep six. jimsam

    35. jimsam said,

      June 28, 2017 at 11:48 pm

      (Learned something new!)

      ok. my bulb blew and the new one stays on. can you leave it on? otherwise it is going in the deep six. jimsam

    36. Ruth said,

      July 20, 2017 at 5:27 pm

      (Learned something new!)

      All I wanted to find out at this time is whether I could get a shock from touching the lamp, which has a “tingly” feel? May find the other info useful if I can get this lamp plugged into another room and working.

    Post a Comment

    I knew this already. I learned something new!