Re: Problems! Disk ][ drive just whirs and whirs; IIc monitor knob stuck; IIe enhanced not...

[Gregory Weston <uce@splook.com>]

In article <stedman-D71606.07532029042007@news-server.stny.rr.com>,
 Larry Stedman <stedman@binghamton.edu> wrote:

> Motherboards on the 2 unenhanced are both 1982
> with a number 820-0064-B   (Or is the last 8?  Maybe B given Matt's info 
> about revision A.  )  There is also a number underneath that in white:   
> 607-0164-M on one and the other lacks the letter.
> 
> The enhanced is from 1984.  
> 
> I tried comparing them to see I could spot the board differences--they 
> look identical!  Then realized from David's comment that it's not that 4 
> new, *extra* chips were added-- just the electronic innards of the chips 
> that were changed.  I had thought I could spot a CPU chip that would be 
> marked 6502 or 65C02---would have been too easy!
> 
> Is there an easy way to tell if these unenhanced have the 65C02 and/or 
> the newer character generator ROM?    IIRC, one can run certain programs 
> that use MouseText to check the character stuff.

Not sure about the queickestway to check the CPU.

For the ROM, check address fbc0 (64448). On an original //e it's $EA and 
on an enhanced it's $E0, and that's the Apple-recommended way to tell 
the difference in code between those two machines specifically so it had 
better be reliable.

You can see MouseText with this (typed with slight modifications from 
the users' guide):

10 PRINT CHR$(4); "PR#3: INVERSE
20 PRINT CHR$(27); "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_"; CHR$(24)
30 NORMAL


> The 1988 platinum IIe with a numeric keypad must have been a lot 
> wider... but sounds cool.

Nope. They just jammed the existing keyboard way to the left.