From: fake@ddress.no   
      
   On Fri, 13 May 2022 11:52:25 -0000 (UTC), phigan   
    wrote:   
      
   >a C64 that powers on with just a   
   >black screen   
      
   The most useful tool for troubleshooting a black screen C64, is the   
   Dead Test Cartridge. Note that a black screen and a blank screen are   
   fundamentally different.   
      
   Throwing parts at it is a lottery. If you want to continue the   
   lottery, the RAM chips are a very common fault. The bad news is,   
   there's eight of them (or two if you have a later revision). Leave the   
   computer on for a minute or two and check for hot RAM chips. If they   
   get hot, they are definitely bad, but they can also be bad if they are   
   not getting hot. The Dead Test can sometimes tell you which specific   
   RAM chip is bad.   
      
   Another common problem is the power switch. It switches both the 5 V   
   DC and the 9 V AC. If the 5 V DC is not working, you will get a black   
   screen on the earlier revision (the longboards).   
      
   Have you checked voltages? That should come before even the Dead Test.   
   --   
   RoRo   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)