[Coco] Apple 2 Plus

[gene heskett]

On Wednesday, June 22, 2011 05:19:51 PM Steven Hirsch did opine:

> On Wed, 22 Jun 2011, gene heskett wrote:
> > But it has classic symptoms of bad ram and never completes the Apple
> > version of post, showing 2 byte wide patterns of black and white
> > squares with question marks in the white squares, and the digital
> > racket of a crashed system overlaid over that.  Many of the chips
> > look as if they need a half hour bath in fresh Tarnex to remove the
> > black oxide of 32 years growth on the legs since it was assembled in
> > 1979.  That might fix it, provided the chip sockets were also
> > similarly de-oxidized, well rinsed and dried.
> 
> When working correctly:
> 
> If that machine has the "autostart" ROMs (and I believe all ][ pluses
> will), you should get a "beep" and a startup screen that says (from
> memory, mine are all in the garage loft) "APPLE ][+" in 40-column text.

Never gets there, nor do any of the drive access leds show any activity.

> It will then try to boot from Slot 6.  Hit Ctrl-Reset and you should get
> another "beep" and see the basic prompt "]".
> 
> I think you're on the right track with the de-ox approach.
> 
> Another thought: The power supplies do not tend to age well, so it's
> worth checking all voltages.
> 
I have checked those + voltages, 4.98 for the +5, and 11.82 for the +12, 
but I haven't located the -5 or -12 if those old dram chips (416's) use 
them.  Right now I have a friend checking his stock for a 74LS367, one leg 
came off of one of them when I was extracting them to attempt a leg 
cleaning.

Those voltage were checked against the PSU case for ground as I'm not sure 
what land is ground on the mobo.

I can see why they don't age well, the PSU box is pretty warm after an 
hour.  Shoulda had more fans, or faster switches.  In 1979, the state of 
power switching semi's was not exactly fast so there was a lot of ohmic 
losses during the switching interval, and the Vsat voltages hadn't yet been 
reduced to the millivolt area, so they ran warm.  Ferrites have come a long 
way too.

> > OTOH, what would it draw on fleabay if it was working?  Heck, I see
> > non- working for $300+, and another barebones that works at 50 bucks.
> > I was under the impression they were worth about 2x that.
> 
> The ][+ is not particularly rare, despite what a lot of eBay sellers
> seem to think.  If it was absolutely mint you _might_ get $2-300 for it
> with the original disk drives.

One used to be able to get ebay to spit out what the item has sold for in 
the past, but its not obvious how to do that today.
 
> If you do get it running, check out 'ADT'.  This utility will let you
> cold bootstrap the machine from a downloaded image on the PeeCee (Linux
> supported, I believe) and generate system diskettes.
> 
> Feel free to contact me privately with any/all Apple 2 questions.  I
> know the machines inside out and did a fair amount of commercial
> development on them "back in the day".
> 
> Steve

Thanks Steve.

Cheers, gene
-- 
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
For most men life is a search for the proper manila envelope in which to
get themselves filed.
		-- Clifton Fadiman