33884Re: [midatlanticretro] Intertec Superbrain
- Jan 2, 2014
---In firstname.lastname@example.org, <pet4032@...> wrote:
>Is this the same Superbrain that you couldn't find a good EPROM to dump? Where did you finally find one?
Happy New Year Bryan,
Yes, the same one. Well, it turned out in the end my eprom was not bad / blank at all. Dave Dunfield solved a 27 year old (forgotten) mystery for me. As it turns out, not all 2716's are interchangeable. The TMS2716's from Texas Instruments and Motorola require 3 voltage rails, while the later 2716's from Intel and a dozen other makers only required a single 5V. I remember using these single 5V Eproms 27 years ago and was baffled that they only used 5V when I had a data sheet at home for the TMS2716. Information back then wasn't easily found like it is today, so I forgot about it. My regular eprom programmer requires an adapter for the TMS2716, which I didn't notice. My first step in trouble shooting is to do a dump of the eprom, for good measure. Which is why I never continued the job. Turned out that the Z80 CPU was bad... that's my 3rd bad CPU chip for 2014. Which is funny, because I haven't seen many CPU chips go bad.
Anyway, lesson learned. TMS2716 <> xx2716
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