New Mockingboard 4c board is preparing

Another Revision of PCB was ordered and I'm waiting for it.

 

In the first design, I used AY3-8912 and good parts going to hard to obtain so change it to AY3-8910 chips.

And now, 6522 part also getting harder to find good one And more failure rates are too many.

So, Tried it to use 65C22 but it doesn't fit well and needs to change circuit redesign.

Designing a new device isn't simple due to old vintage parts need to be provided properly.

it is harder to obtain good working parts.

 

Due to a lack of good working parts, I also considered replacing it to CPLD but, it isn't good mate for vintage APPLE II so didn't emulate it and now CPLD is just used to replace some of TTL chips.

 

Once it finished, I could prepare enough amounts of MB4c board.

Please wait more time for it.

 

Thanks a lot

Ian Kim