From: pafoxp@x14all.kpn   
      
   On 26-04-2023 22:48, Jeroni Paul wrote:   
   > Peter X1 wrote:   
   >> Are you sure its must be 1.2V which seems to me for a LCD monitor   
   >> somwhow strange. Whatś the input voltage of the "regulator" ?   
   >>   
   >> I think feeding things with 1.8V, providing doing this with low current,   
   >> will not harm things. If you habve a bench power supply, give it a slow   
   >> try.   
   >>   
   >>   
   >> --   
   >> Mvg...   
   >> Peter   
   >   
   > 1.2V is the measured voltage, I can't properly measure the voltage setting   
   resistors because the circuit effect. I hacked the resistors to increase the   
   voltage to 1.8V with no difference.   
   >   
   > I identified the reset input, it is implemented with a 10uF electrolytic   
   just like the similar manual I pointed and it is fine. I scoped the crystal   
   and it is oscillating with 0.8V amplitude centered around 1.7V, I guess it is   
   fine. So it seems the    
   micro is dead. No attempt to read the flash memory, as soon as the reset goes   
   low both SDA and SCL go and stay low.   
   >   
   > I am seeing 15 ohm resistance in the 1.2 / 1.8V line. From my experience   
   this is normal with some processors but maybe with this one indicates an   
   internal short.   
      
      
   You could  try to scope the voltage which should have no circuit effect.   
   Powering thingsvia a resistor divider network seems odd to me, perhaps   
   it act as reference only.   
      
   Difficult to investigate without datasheet/reference. Try to find pins   
   that may do "something" and work your way up or as last resort,   
   (de/solder skills required & risk to damage) swap the chip.   
   Before that, I would check the electrolytic conndensators first.   
      
      
   --   
   Mvg...   
   Peter   
      
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