blog:commodore_pet_restoration

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
blog:commodore_pet_restoration [2021/11/25 11:18]
john [Powering On]
blog:commodore_pet_restoration [2021/11/25 21:26] (current)
john [Cleaning]
Line 30: Line 30:
  
 ==== Keyboard ==== ==== Keyboard ====
 +
 +The first thing to do at this point was to make sure that I was able to type and that the computer was actually responding to user input... well, this didn't //quite// go as planned:
  
 {{:blog:blog:commodore:pet:img20211124205025.jpg?400|}} {{:blog:blog:commodore:pet:img20211124205025.jpg?400|}}
 +
 +That screen is the result of pressing //every// key on the keyboard. It's plainly obvious that the keyboard has an issue at this point. The first course of action with a malfunctioning keyboard is always to try cleaning the contacts, and it was quite simple to do this with the old PET:
  
 {{:blog:blog:commodore:pet:img20211124205953.jpg?400|}} {{:blog:blog:commodore:pet:img20211124210429.jpg?400|}} {{:blog:blog:commodore:pet:img20211124205953.jpg?400|}} {{:blog:blog:commodore:pet:img20211124210429.jpg?400|}}
 +
 +Keyboard traces and plunger contacts cleaned with alcohol - they were dusty, but in really good condition.
 +
 +Back together and every key tested:
  
 {{:blog:blog:commodore:pet:img20211124211850.jpg?230|}} {{:blog:blog:commodore:pet:img20211124211856.jpg?400|}} {{:blog:blog:commodore:pet:img20211124211850.jpg?230|}} {{:blog:blog:commodore:pet:img20211124211856.jpg?400|}}
 +
 +Result! 100% working keyboard 8-)
 +
 +==== Cleaning ====
 +
 +Cleaned the inside of the case and sprayed the spots that were starting to rust with a clear lacquer to stop it spreading:
 +
 +{{:blog:blog:commodore:pet:img20211125200543.jpg?500|}} {{:blog:blog:commodore:pet:img20211125200549.jpg?500|}}
 +
 +Side of the case half done, with it partially cleaned its easy to see just how dirty it really was:
 +
 +{{:blog:blog:commodore:pet:img20211125202157.jpg?500|}} {{:blog:blog:commodore:pet:img20211125202201.jpg?500|}}
 +
 +Rear of the case has some nasty glue residue from what looks to have been packing tape or possibly even duct tape. Not sure why anyone would have tape stuck to the back of the case??? Also cleaned up the really interesting original supplier case sticker.... they are //long, long// gone now.
 +
 +{{:blog:blog:commodore:pet:img20211125205816.jpg?500|}} {{:blog:blog:commodore:pet:img20211125205837.jpg?500|}}
 +
 +Case all cleaned and back together. Looking much smarter:
 +
 +{{:blog:blog:commodore:pet:img20211125205930.jpg?500|}} {{:blog:blog:commodore:pet:img20211125205940.jpg?500|}}
 +
 +Motherboard before and after. I decided with the age of this thing not to go too wild - in the end I just used a soft brush to clean the majority of the dust away and then used alcohol to clean off the tarnished edge connectors. I didn't want to go to the extent of rinsing the entire board.
 +
 +{{:blog:blog:commodore:pet:img20211125203600.jpg?500|}} {{:blog:blog:commodore:pet:img20211125204321.jpg?500|}}
 +
 +==== SuperSoft HR40 Connections ====
 +
 +I took images of how the SuperSoft HiRes graphics board was connected, as it's not just inserted into a ROM socket, but has 3 chip test-leads clipped to the legs of 3 seperate chips.
 +{{:blog:blog:commodore:pet:img20211125203812.jpg?500|}} {{:blog:blog:commodore:pet:img20211125203820.jpg?500|}}
 +
 +{{:blog:blog:commodore:pet:img20211125203833.jpg?500|}} {{:blog:blog:commodore:pet:img20211125203840.jpg?500|}}
 +
 + Also something that I did not notice earlier is a stacked (DRAM?) module, soldered on top of another module. This is also definitely non-standard:
 +
 +{{:blog:blog:commodore:pet:img20211125203849.jpg?500|}}
 +
 +==== Bodge Wires ====
 +
 +On the underside of the board are a small number of bodge wires. They're not held on particularly well, so I don't suppose they are factory fit:
 +
 +{{:blog:blog:commodore:pet:img20211125204001.jpg?400|}}
 +
 +{{:blog:blog:commodore:pet:img20211125204017.jpg?300|}} {{:blog:blog:commodore:pet:img20211125204022.jpg?300|}}
 +
 +==== BASIC 2 Easter Egg ====
 +
 +The PET BASIC V2 easter egg indicates that it has a V2 BASIC ROM (which it should, for a 2001 with full-size keyboard, unlike the early chiclet key model):
 +
 +<code>
 +# The command is:
 +WAIT6502,
 +# Where X is a positive integer and the number of times the easter-egg string is printed
 +</code>
 +
 +{{:blog:blog:commodore:pet:img20211125205803.jpg?500|}}
 +
 +
  • blog/commodore_pet_restoration.1637839090.txt.gz
  • Last modified: 2021/11/25 11:18
  • by john