Reply 20 of 24, by kool kitty89
I just got 4 of these and all appear to be DOA. I'll deal with the seller/ebay, etc (and probably double-check them in the process).
Tried at 8 (de-turbo) 20 and 25 MHz on my no-name variant of a PCChips M-205 (with Citygate D60 chipset AKA Hedaka D60, CG logo might be fake on mine, but PCChips used CG chipsets earlier on, and there's no 205 mark on my board, even, so might be vanilla markings).
I installed a socket for the oscillator and swapped in a 50 MHz one for the test. The original 20 MHz Harris CPU posts and seems to work fine (no disk drive hooked up currently) at 25 MHz with 60 ns CMOS DRAM installed, though. (I let it run warm for a while, too, and it still posted again; granted these CMOS Harris 286s seem to run fairly cool at high clock speeds ... not like an NMOS Intel 286-12 I nearly burned myself on)
Anyway, since Tiido and some others seem to have gotten working examples, maybe I just got a bad batch. OTOH, if they're remarked, they're also not ideal for what I had planned: trying to push the limits of the D60 chipset (and maybe some others I can get my hands on) beyond 25 MHz, or at least no better than randomly selected original 20 MHz parts would.
Also, most (or all?) real Harris 286 20s aren't engraved, but use white print on a satin/smooth surface finish, not the rough/stippled texture on these. The print is also somewhat larger and covers more of the surface.
Like these 20 MHz ones (apparently from the late 90s)
I'm tempted to try some of these other ones.
Harris part number and looks like the print style and finish of real ones, but missing the Harris logo and name. And from 1991, so long before the 1999 Intersil spinoff company was created, but maybe some were marked like that.