More free stuff!
Posted: 05 Jan 2015 00:07
Hi folks,
You may be aware of the fake CMOS Z80s that we have found recently. The chips were marked as 20MHz CMOS Z80s, but were anything but!
Lez sent me a batch of additional CPUs for testing to assess the quality that he was getting from a couple of Chinese suppliers, testing has shown that they are not what the labels say they are, but they are still functional at lower speeds.
The chips are :-
NMOS
1 runs at 2MHz
2 runs at 4MHz
3 runs at 8Mhz
4 runs at 4MHz
5 runs at 4MHz
6 runs at 4Mhz
7 runs at 2 Mhz
So, they look like a mixture of Z80, Z80A and possibly a Z80H or maybe it's just a "B" that can be overclocked a little.
CMOS
1 runs OK at 8MHz
2 runs OK at 8MHz
3 runs OK at 8MHz
4 OK at 16MHz
5 OK at 16MHz
6 runs OK at 8MHz
7 OK at 8 MHz
8 OK at 16MHz
9 OK at 8 MHz
10 OK at 8 MHz
So, they look like 10MHz CMOS, remarked as 20 MHz
If anyone is interested in having a couple of these for the cost of postage, perhaps as spares for slower systems, including MTXs, let me know.
Regards
Dave
You may be aware of the fake CMOS Z80s that we have found recently. The chips were marked as 20MHz CMOS Z80s, but were anything but!
Lez sent me a batch of additional CPUs for testing to assess the quality that he was getting from a couple of Chinese suppliers, testing has shown that they are not what the labels say they are, but they are still functional at lower speeds.
The chips are :-
NMOS
1 runs at 2MHz
2 runs at 4MHz
3 runs at 8Mhz
4 runs at 4MHz
5 runs at 4MHz
6 runs at 4Mhz
7 runs at 2 Mhz
So, they look like a mixture of Z80, Z80A and possibly a Z80H or maybe it's just a "B" that can be overclocked a little.
CMOS
1 runs OK at 8MHz
2 runs OK at 8MHz
3 runs OK at 8MHz
4 OK at 16MHz
5 OK at 16MHz
6 runs OK at 8MHz
7 OK at 8 MHz
8 OK at 16MHz
9 OK at 8 MHz
10 OK at 8 MHz
So, they look like 10MHz CMOS, remarked as 20 MHz
If anyone is interested in having a couple of these for the cost of postage, perhaps as spares for slower systems, including MTXs, let me know.
Regards
Dave