From: legg@nospam.magma.ca   
      
   On Wed, 6 Sep 2023 20:38:27 +0200, Arie de Muijnck    
   wrote:   
      
      
   >> I see no I2C data traffic to the lamp control IC U2   
   >> - both lines pulled low.   
   >   
   >That is an illegal state, I2C idle is both lines high.   
   >This indicates a double short, or a bad 16-bit expander.   
   >   
   I realize that, which is why I mentioned it. Double shorts   
   being hard to come by . . . .   
      
   Remeasuring after hardware/factory reset shows both lines   
   floating high, now, with no short. The TCA1116 is unobtainium.   
      
   Though TI flogs a pin-compatible replacement, they refuse to   
   supply the original TCA1116 data sheet, for performance, address   
   and power sequencing comparisons. They will provide the old   
   data, through email, only to registered users of E2E support.   
   Why the shyness?   
      
   The working white and blue LEDs are driven directly from the   
   main control chip.   
      
   The 0/1 switch feeds a crude SW/HW reinforced latch.   
      
   RL   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)