From: legg@nospam.magma.ca   
      
   On Wed, 21 Sep 2022 03:00:54 -0700 (PDT), Jeroni Paul   
    wrote:   
      
   >Ralph Mowery wrote:   
   >> The LED replacements did not come ito use before I retired. The   
   >> elecrtronics were not in use for too many years before I retired so can   
   >> not coment on their lifetime.   
   >   
   >I am disappointed with their reliability. I maintain the lights in my bloc of   
   flats and the lift lights years ago used CFL GU10 type bulbs. They were rated   
   a lifetime of 20000h which are 2.5 years as they are always on and they   
   actually lasted about 3.5    
   years.   
   >   
   >Three years ago I installed GU10 led bulbs with a rated lifetime of 50000h,   
   that's 6 years! After two years both bulbs failed with blinking lights. They   
   did not even reach the rated lifetime of CFL. I also see many TV led   
   backlights fail more often than    
   CFL. For now I consider CFL quite more reliable than led.   
      
   There's a lot of bad design/assembly choices being made in led   
   replacements for long-tube ccfl replacements.   
      
   These stem from thermal expansion differences between the led chip   
   carrier medium and the housing. FR4 doesn't cut it.   
      
   The use of adhesive  simply causes bowing and thermal isolation,   
   with added mechanical stress on the joints and thermal stress   
   on the semiconductor.   
      
   The addition of screw tie-points doesn't correct for this - it   
   simply determines where the bowing will occur.   
      
   Only those strips that use a viable thermally conductive substrate   
   and a slide-able attachment scheme can benefit from semiconductor   
   reliability, to demonstrate a long operating life.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)