Commodore 64 Repair - 250407 Rev B Mainboard with Scrambled Screen - What a Lovely Thing to Work On.

This is so Nostalgic for me as my first computer was a Commodore 64 Breadbin purchased brand new in 1984 by my Mum for $595 from Supatech Electronics in Mt Eden, Auckland New Zealand - Got it home unboxed it set it up on a TV turned it on and it produced garbled text with random characters appearing on the screen and was faulty so it was returned the next day and swapped with another C64 breadbin and a voucher for $40 off my next game. Next visit we called in and i chose Raid Over Moscow on cassette, took it up to the counter and there was a loud bang outside the shop and my mum said that's my car and we went running out to find a lady driving her bosses car for the first time and it had bull bars fitted front and back and she ripped the front bumper completely off my Mums Mitsubishi Mirage Car - 1984 Great Year Good Times (obviously not the car bumper being ripped off) that i remember like it was yesterday - $5 C64 games on disk from Abacus Computers/Rosebud Video Games and a Freeze Frame Mk3b Cartridge purchased from them in 1985 - Thanks Frank...

Onto The Repair - This Commodore 64 started off with a black screen and a SID chip that was getting way too hot, removing the SID and the C64 had a scrambled screen with garbled text - U14 a MOS 7709 74LS258 multiplexer was my first suspect as it is a MOS branded part and bad TTL logic will produce garbled startup screens - my lucky day as the fault turned out to be caused by U14 and no bumpers were ripped off - A Most Enjoyable Repair ! - Good times again...