Re: A2 Rev 0 Recreation Update #2

[Mike Willegal <mike@willegal.net>]

Thanks Michael,

I had purchased series crystals thinking that is what the Apple 
required, as there are no capacitors in the circuit.  Also, I think I 
saw an old newsgroup post that mentioned that the Apple took series 
crystals.  I should be getting a batch from a different source today. 
We'll see how they work.  This might be the excuse I need to get that
meter with the frequency counter, I've been thinking about.

Thanks for the reminder about the disk formatting business.  I had 
formatted the non master disk I was trying to boot on a 48k system.  I 
do remember that master.create only works in slot 7 for the original DOS 
3.1, though (selective memory, I guess).

Regards,
Mike Willegal

www.willegal.net

Michael J. Mahon wrote:
> Mike Willegal wrote:
>
> > Hi Folks,
> >
> >   After taking my time soldering on the components, I powered on 
> > yesterday with 16k of memory installed.  Initially I got no video. 
> > Probing found no clocks at all.  Traced it down to wrong transistors 
> > in clock circuit.  After taking the right ones from an old rev4 board, 
> > it came to life, but no text - video mode only.  I found a bad IC.  
> > The 74166 at location A3 had a bad output.  I did another swap from 
> > the rev 4 board and now I had a text prompt, but no color.  Swapped 
> > the crystal from the rev4 and color appears. 
>
>
> There are two types of crystals:  series resonant and parallel
> resonant.  Sounds like you need the "other" type (and I don't
> recall which it is ;-).
>
> > Tried booting DOS and it dropped to monitor instead.  After thinking 
> > about it a while, remembered that I needed more than 16K ram to run DOS.
>
>
> If you boot a DOS "master", 16KB is enough.  But a "slave" DOS will
> require/use as much RAM as the machine it was INITed on (unless you
> convert it to a master using MASTER CREATE on the DOS Master disk).
>
> >  Filled up memory to 48k and now I could boot DOS.  Booted from all 
> > the slots successfully.  Next I checked out the pdl and switch inputs 
> > - all work fine.  I still have to check out annunciator outputs, Slot 
> > 0 functionality, cassette I/O and a 4K memory configuration.
> >
> >   The bottom line is that, except for some minor component issues, 
> > things are looking real good.  It will take a few more days to check 
> > out remaining functionality and probably several more weeks to sort 
> > out remaining component issues and put together a rough guide to 
> > building and bring up the board.
>
>
> Sounds good!
>
> >   I put some preliminary information on my site about availablity and 
> > cost of kits.  Goto the apple II recreation page for more information.
> >
> > Regards,
> > Mike Willegal
> >
> > www.willegal.net
>
>
> -michael
>
> NadaPong: Network game demo for Apple II computers!
> Home page:  http://members.aol.com/MJMahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."