Re: v20-16, z80-20 and chip counterfeits

Hi all,

does anyone know a reliable source for a WD2793 floppy controller ic, I have been looking on ebay and am also concerned that many of the TMS2793 look suspicious, too many suppliers with identically printed/date coded chips. I can believe that there is a large stash of these parts in China.

the whole fake IC this is very frustrating, I buy from reputable suppliers where possible but many of these chips are obsolete/not stocked.

wrt 20mhz Z80 CPU , Mouser has 119 DIP's on order with an estimated delivery of 3/10/2014 for those who can wait

http://uk.mouser.com/Search/Refine.aspx?Keyword=z84c0020

regards

David Fry
On Sunday, June 29, 2014 3:44:02 AM UTC+1, curt mayer wrote:

I've got a 8088 cpu blank, and a z80 cpu populated. I bought a 10 chip lot of z84c0002pec's from ebay, and was a bit horrified when I got them to find
that they smelled of new paint. identical fronts, but the backs showed different countries (indonesia and phillipines), all with different mold imprints.

obviously shenanigans.

so, I wired up a 20mhz test rig for the z80's, using a derivative of dunfield's no-ram monitor (i disassembled it and added a lot more code), and not a one tested

out at 20 mhz. one limped at 16, 2 ran at 12, and the rest were good at 8. all tested as cmos: the out (C),F instruction sends FF, the nmos sends 00.

for 15 bucks, I got a bunch of mildly useful z80s of unknown actual characteristics.

anyhow, now i want to build the 8088 board with V20's - NEC has a part number for dip-40's at 16mhz. 70108hcz-16. lots of them available on ebay from china.

any experiences here before I become the ebay counterfeit chip crash test dummy?

--curt