Okay, so things are Not Good...
I programmed the 27C100s.
I made the 28->32 pin adapters, wiring pins 30,31,32, and 1 together. Pin 24 (so 22 on the motherboard socket) was wired to Pin 2 on the adapter. Pin 24 on the chip was wired to pin 16 (14 on the motherboard) to ground Output Enable. The are no shorts anywhere that I can see.
I fitted them into the A500 (leaving pins 1,2,30 and 31 outside the sockets) and... nothing.
I then put the original eproms back in. Still nothing.![:shock:]( "Shocked")
The new adapters all read fine in a TL866 when only the lower 28 pins are used and it thinks it's reading a 27512.
Testing with the logic probe, all the address lines are active whilst reset is pressed. As soon as Reset is released, they all go Low, except for A0-A2 which still show some activity.
Any suggestions?
I programmed the 27C100s.
I made the 28->32 pin adapters, wiring pins 30,31,32, and 1 together. Pin 24 (so 22 on the motherboard socket) was wired to Pin 2 on the adapter. Pin 24 on the chip was wired to pin 16 (14 on the motherboard) to ground Output Enable. The are no shorts anywhere that I can see.
I fitted them into the A500 (leaving pins 1,2,30 and 31 outside the sockets) and... nothing.
I then put the original eproms back in. Still nothing.
The new adapters all read fine in a TL866 when only the lower 28 pins are used and it thinks it's reading a 27512.
Testing with the logic probe, all the address lines are active whilst reset is pressed. As soon as Reset is released, they all go Low, except for A0-A2 which still show some activity.
Any suggestions?
Statistics: Posted by Boydie — Fri Dec 20, 2024 7:29 pm