Several years ago I bought a number of Dallas DS1216E modules from AliExpress.
The DS1216E is functionally identical to the SMT No-Slot-Clock.
After a bit of surgery to grind out the epoxy underneath it and disconnect the internal (dead) button cells, I connected some modern CR2032 cells to each of the chips via some leads and a coin cell holder.
I had four working No-Slot-Clocks as a result in 4 different machines. One of them runs 24-7 hosting a BBS.
The other three were in machines storage with the power cells disconnected.
So yesterday I reboot my machine and it doesn't recognize the clock. Change battery. Nothing.
Plus it gives weird ROM based errors (that go away when the clock is removed) - the clock sits beneath the CD ROM chip on a IIe.
No problem, I say...I'll get a backup clock. Nope. It doesn't work either.
OK, I'll try one of my storage machines - they won't work either and present the same funny ROM issues with random crashes while in the "BYE" routine in ProDOS.
In the end I now have four DS1216E chips that all seemed to have failed. This is something I have never seen before. Has anyone else?
I'm now in a position where I have no clock in my IIe and really could use one.