ebay PL: QARTZ ATARI CO12285 (C012285) - Ersatz für ATARI 600XL & 800XL.
A new replacement for the CO12285 quartz, which was present in the Atari 600XL,
800XL without the FREDDIE chip. The operating frequency of this quartz was 3.546894 MHz PAL.
There is a replacement for this quartz in this listing. It is a quartz generator,
which is installed in place of the 74LS74 integrated circuit on the Atari motherboard.
It is shown in this video:
https://www.youtube.com/watch?v=cgpVeSi2Grg
We don't have to solder anything, just remove the 74LS74 chip and put the generator in its place.
Gtx,
andY
!