From: ohg...@gmail.com   
      
   On Thursday, June 15, 2023 at 1:02:30 PM UTC-4, john wrote:   
   > Any ideas as to what would cause a CRT to take 10mins to warmup before it   
   displays anything? Maybe old capacitors? This thing is a 55 year old   
   calculator.    
   >    
   > -John   
      
   Does the display suddenly appear nice and bright after 10 minutes of darkness   
   or does it slowly fade to life?   Either can be circuit component issues but a   
   slowly appearing image sounds like a very tired CRT.  If it's the latter and   
   the machine hasn't    
   been used in many years, then just running it several hours a day will   
   generally perk  up a tired CRT.   
      
   If the image appears suddenly and looks good, then it's most likely a circuit   
   issue.  A service manual would be handy in checking to see if the heater   
   voltage and HV appear immediately (the two most likely issues).  If all the   
   voltages are good, then you    
   need to scope the grid of the CRT backwards and see where you are losing you   
   video.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)