15 Apr
2002
15 Apr
'02
4:21 a.m.
Sellam Ismail wrote:
On Sun, 14 Apr 2002, James B. DiGriz wrote:
Different VDP's, as Frank mentioned, and different ROMs. The 4A adds
lower case ASCII characters, etc., The /4 has an equation calculator
mode missing from the /4A. There are other minor differences that mean
some /4A cartridges and disk software don't work on a /4.
Don't recall if it's the same PWB. I have one of each machine apart
somewhere around here and can look if you're interested. You're right,
though, there is no substantial difference between them. It's entirely
possible there's a /4A board in the Insight, just more likely a /4, in
my view. If it isn't something else entirely. It's possible if not
likely the terminal has its own ROMs, regardless.
By the way, I'm hearing of yet another prototype machine that has an
80-col display.
jbdigriz
Being this
was made in 1981 (according to the page), and based on the way
TI did things, I would not be surprised if there was a TI-99/4a at the
core of this machine, with the carthridge slot used to throw different
applications onto the machine for various data communications scenarios.
I'm guessing this was a way to sell /4 mainboards still in inventory
after the /4A was introduced, among other things. The mainboard might
have been redesigned specifically for the Insight, though, which is one
of the things I'd like to find out. From my understanding, the TI-99/4 and 99/4a are
the same save for the
keyboard.
Are there any motherboard differences? I wouldn't think so.
Sellam Ismail Vintage Computer Festival
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