Physical differences between the Apple III and III Plus

[Andrew T.]

How was the Apple III Plus physically different from the original III?

From what I've read, some of the differences were simple matters of specification: A modified keyboard layout, more memory, interlacing, a built-in clock. Were any components integrated or rationalized as well? The III Plus also supposedly solved the III's thermal problems. But how? What special trick of engineering was applied to make the model reliable; given that the form factor and fanless construction stayed the same?

 

[david__schmidt]

You've got the gist of it already. There isn't anything else. The thermal problems were somewhat lessened by the use of the 5v memory board vs. the 12v one; and the closeness of the traces on the circuit board was attributed to most of the failures, not really heat. That was solved in the later revision of the III, not the plus. So the plus was really about a facelift, and an attempt at a new lease on life - riding on the coattails of the good name of the Apple II plus, hoping people would make that mental association.

There is a YouTube video out there that has Jerry Manock (designer of the Apple III case) talking about, and fairly defending, the Apple III case. I'm sorry I don't have a pointer to the exact point where he does that, and the video is over an hour long... but it's very interesting about Apple industrial design from the Computer History Museum:
http://www.youtube.com/watch?v=--7Br07QKMk

 

[dorkbert]

the III+ also switched to DB19 type connector in the rear for external floppy drive.
There was some guy on fleaBay keep trying to pass off a III as a III+ by swapping the cover with III+ tag.

 

[david__schmidt]

the III+ also switched to DB[25] type connector in the rear for external floppy drive.

Oh, that's right - and the trouble with that is (besides there being approximately zero Disk III drives with DB25 connectors - but there are adapters out there) it's the same connector as the serial port.

http://apple3.org/Documents/Technotes/TA29457.html
http://apple3.org/Documents/Technotes/TA31434.html

 

[Andrew T.]

the III+ also switched to DB19 type connector in the rear for external floppy drive.
There was some guy on fleaBay keep trying to pass off a III as a III+ by swapping the cover with III+ tag.

The early IIIs and drives used a ribbon cabble, I assume? Shockingly, the actual Apple website still references this: http://support.apple.com/kb/TA31434

There is a YouTube video out there that has Jerry Manock (designer of the Apple III case) talking about, and fairly defending, the Apple III case. I'm sorry I don't have a pointer to the exact point where he does that, and the video is over an hour long... but it's very interesting about Apple industrial design from the Computer History Museum:
http://www.youtube.com/watch?v=--7Br07QKMk

Thanks for the info and video link! I'll check it out.

 

[vwestlife]

There is a YouTube video out there that has Jerry Manock (designer of the Apple III case) talking about, and fairly defending, the Apple III case.

This may be a myth, but the story goes that Steve Jobs gave the Apple engineers the dimensions he wanted the III's case to be, and they did the best they could to make all the circuitry fit inside.

It was rather pointless for Apple to release the III Plus, because the IIe was already out by then, which included many of the features that originally were unique to the III (more RAM, 80-column display, and SOS-based ProDOS). Maybe if the III+ had included full IIe emulation, it could've caught on, but it was still restricted to emulating only a 48K II+ with a 40-column display.

 

[david__schmidt]

Maybe if the III+ had included full IIe emulation, it could've caught on, but it was still restricted to emulating only a 48K II+ with a 40-column display.

I have read, again perhaps anecdotally, that the II+ hobbling decision was a deliberate one - to separate the III from the home/game/education market. On the other hand, incorporating the additional logic for the IIe would have been an added engineering expense at a time when Apple was just trying to shift the inventory out.

 

[NeXT]

Apple never marketed the III for schools or home. It was the "small business" computer while the Lisa was their "big business" machine. The plan to cripple to a II+ was so that you had to buy the updated Apple III software that was available (and screw yourself over if you also bought Catalyst).

 

[njroadfan]

There was a third party board called the "Titan /// plus //e" that upgraded the hardware to run Apple IIe software. What exactly were the Apple ///'s unique video and sound capabilities anyway? No one seems to have documented them outside of vague terms like "business audio" and such.

 

[vwestlife]

What exactly were the Apple ///'s unique video and sound capabilities anyway? No one seems to have documented them outside of vague terms like "business audio" and such.

The III has 16-color RGB video, although in II+ emulation mode, hi-res graphics come out as monochrome, because it doesn't mimic the NTSC color bleed effect like the way the IIGS does. It also has a color composite output, although I doubt color graphics really ever got much use in Apple III software, because it was almost always bundled together with the matching green monochrome Monitor III.

As for the III's text and graphics capabilites:

Four Graphics Modes:
280 x 192, black and white
280 x 192, 16 colors, foreground and background
140 x 192, full 16 colors
560 x 192, black and white

Three Text Modes:
40 x 24, black and white, normal and inverse
80 x 24, black and white, normal and inverse
40 x 24, 16 colors, foreground and background
All text modes have a software-definable 128-character set

As for the audio capabilities, I have no idea, except for the fact that it has an external speaker output on the back.

Unusually for what was supposed to be a "business" computer is that it has joystick ports on the back, although they don't always work correctly in II+ emulation mode.

 

[Computist]

The Apple ///'s audio consisted of a 6-bit DAC vs. the Apple II's method to create sound, toggling the speaker. There's some interesting sound stuff buried in the WAP DVD, but I can't think of any commercial software that specifically took advantage of it. Apple salespeople at the time were told to emphasize how the improved graphics and sound could enhance business presentations.