Hi crews,
I'm trying to repair a vintage computer circuitry that contains an unknown IC in the DIP-8 package. It was used in several Macintosh computers around 1993/1994.
The IC in question is marked with the Apple logo and contains the following digits: '90 0120'. I attached a zoomed picture of the IC as well a schematic showing the related components.
The IC in question (U12) could be an ASIC. But it could be also a custom version of some other IC like the Cuda MCU (U17) which is just a custom version of the 68HC05.
The unknown IC (U12) is attached to a non-rechargeable 3.6V lithium battery. Its purpose is supposedly to manage the power source for U17 that implements a small nonvolatile RAM. U17 is therefore always powered either by the mains or the battery.
Any ideas on what it could be? Did you ever see anything like this?
Thank you in advance!
I'm trying to repair a vintage computer circuitry that contains an unknown IC in the DIP-8 package. It was used in several Macintosh computers around 1993/1994.
The IC in question is marked with the Apple logo and contains the following digits: '90 0120'. I attached a zoomed picture of the IC as well a schematic showing the related components.
The IC in question (U12) could be an ASIC. But it could be also a custom version of some other IC like the Cuda MCU (U17) which is just a custom version of the 68HC05.
The unknown IC (U12) is attached to a non-rechargeable 3.6V lithium battery. Its purpose is supposedly to manage the power source for U17 that implements a small nonvolatile RAM. U17 is therefore always powered either by the mains or the battery.
Any ideas on what it could be? Did you ever see anything like this?
Thank you in advance!
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