Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

It’s simpler than that.

No idea of the exact scheme, but it’ll be something like when you put in a new cartridge the printer writes the current date & time (obtained from your PC) to the chips.  When a year has passed it writes ‘Dead’ to the chip.

You used to be able to reset chips, now you need to get new ones along with your toner refill after the manufacturers closed that ‘loophole’.

Could be worse, HP at one point were writing the manufacture date to the chips so if you inserted a brand new cartridge you’d had sitting in on your shelf for a while, it would report is as ‘too old’ and kill it.  Nasty.

Tony

If there is a self destruct after one year then there must be a real time clock of some sort, if it's a clock chip then it should be possible to intercept the clock reference by either changing the clock oscillator Cristal for one that has a frequency of 1/2 or 1/4 of the original. If the clock reference is taken from another reference the inserting a device by 2 or 4  IC would do the same. Another option could be to remove the clock backup power source is battery then the clock would always start with its default date/time it just depends on wether the full data time are used or just the day.