XPost: uk.d-i-y, alt.home.repair, uk.legal   
   From: bowman@montana.com   
      
   On 01/04/2022 01:13 AM, Brian Gaff (Sofa) wrote:   
   >  Likewise a number of Sinclair ZX Spectrums in the early days were made with   
   > known faulty ULA chips and a logic chip  glued to the surface with its legs   
   > splayed and wired to make the circuit work.   
      
   When the ZX80 came out it was available as an unassembled kit for $99. I   
   don't remember the exact problem but I had to tweak it ti get it to run.   
      
   Osborne came out with a 100 column conversion for the Osborne 1. CMOS   
   was a new technology and while it normally saved power, dissipation   
   increased with frequency. The circuit would work until the chip got hot.   
   I replace it with the equivalent LS part and all was good.   
      
   Back in those days I could see the components without a microscope so   
   component level troubleshooting was feasible.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)