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   comp.sys.ibm.ps2.hardware      Discussing IBM PS/2 hardware      42,985 messages   

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   Message 41,312 of 42,985   
   Christian Holzapfel to All   
   Re: Trying to repair an Ultimedia Video    
   31 Jan 23 00:32:24   
   
   From: google@holzapfel.biz   
      
   I was having a good day, and swapped Miami. I've never replaced a 240-pin SMD   
   component before, but that's kind of the secret goal of the project:   
   discovering tools, getting hands on digital logic, leaving my comfort zone and   
   becoming a better engineer.   
      
   Used a brutal, large heat gun to get the new Miami off the SSA adapter,   
   carefully heating the zone bit by bit until it fell off, together with a lot   
   of passive components. No serious pin bending there, and they all look pretty   
   clean. Off to a good start.   
      
   Then I rubbed the Ultimedia's Miami pins with Chip Quik flux, and used an iron   
   to attach a proper amount of Chip Quik low-temp solder to the pins. With an   
   SMD hot air station I - more carefully this time - heated up the area until I   
   could pick up Miami    
   from the board with a pair of tweezers.   
   Cleaned up the board with even more flux, solder braid and iron.   
   Then cleaned everything with isopropanol and cotton swabs.    
      
   Applied flux again, and dipped the new Miami into place. Carefully wiggled it   
   until pins were sitting perfectly aligned to the pads. Used a cheap USB   
   microscope to inspect.   
   Then I used a flat iron tip and leaded solder to fixate some of each side's   
   pins to keep Miami in place. Then went around the chip, applying solder to all   
   rows, following with braid to suck up the leftovers.   
   Inspection - cleaning - flux - solder - braid - inspection... you get it.   
   Until no shorts were visible or measureable.   
      
   Going to the bottom side of the PCB, I measured all 0805 sized resistors, and   
   found R202 went up from 4k7 to 6k73. Replaced it - fine.   
      
   Plugged in the card, held my breath, turned on the -42T and.... things remain   
   unchanged -.-   
   No additional failure, but no improvement at all. Still no way of reading out   
   local bus addresses through the MIOBUSGET ioctl, and no successful driver   
   installation.   
      
   So Miami survived the transplantation, but it wasn't the problem's root cause   
   either.   
      
   Now I will replace all off-the-shelf components piece by piece as I find them   
   available for a fair price - can't get any worse than swapping Miami.   
   It's about the journey, right?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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