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Member Since 24 May 2007
OFFLINE Last Active Yesterday, 9:49 AM

#4023253 Need some advice on repairing my 800XL

Posted by 1050 on Tue May 8, 2018 12:42 AM

Yes, those two wires are common on a lot of them.

How about swapping around U26 and U27 for a test to
see if the pattern changes in the self test? Might
need to replace these if we can get it to change by
doing this. At this point it could still be CPU, MMU
and a host of others too, but hey what fun!

There must be a bug in the self test code as usually
three rows is all I've seen. And this could bad ROM
itself or the bug acting only with the particular
defect. At any rate BASIC occupies the last half of
the last row of three.

So your first screenshot if it were all green squares
is what we want to see if it was booted with BASIC ON.
Last screenshot is not possible, but there it is anyway.
I'm leaning towards a failing ROM chip U5 at the moment.

#4020851 WOW! Look what I found in a junk 800 - 3Bit Full-View 80 and ?

Posted by 1050 on Fri May 4, 2018 2:30 AM

My guess would be that somebody needed the ROM card
so they took it.

Layout you report is NOT right by the Bit 3 diagram.
I'm thinking the directions on the 'jump back board'
are too open to improper interpretations?

S.C.S.D. appears to have owned CSS at one time.
Probably before Bob Puff took over CSS at least that
is what I can gather from an ad for the "Pill" in
a Compute magazine that google hit on. page 60

Oh look an ad for a new 1050 - only $349!
16K board for the low, low price of $89...

Back in those days I couldn't even afford a baloney
sandwich for lunch let alone an issue of Compute.

Would be nice to know the numbers off those ram chips
on the 16K S.C.S.D. board, can't read from the picture.
Have my suspicions that the 16K board might be axlon
type ramdisk and the switch on those typically turned
the extended memory off. Never understood really why,
unless they just did that because they could.

You should maybe buy a lottery ticket?
I thought I was lucky when I found a Happy in a
$25 goodwill 1050.

#4020837 Rana 1000 - loose part inside

Posted by 1050 on Fri May 4, 2018 1:41 AM

That's the commutator end for all those motors, there
would be brushes inside making interference and
according to the FCC you can't do that way back then.
So the disc puts them in compliance mainly would be
my guess. I doubt any TV viewers were affected in any
case, prime time has been dead so long now it doesn't
even stink anymore.
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#4018151 Atari 800 xl acting strange.

Posted by 1050 on Mon Apr 30, 2018 7:26 AM

Ah, a programmer! :)
Positively no good then, resume with Vyper68 in post #14
and change out U24 and U25 for new 4051 chips as a
last ditch effort before moving on to keyboard jack
connection problems or mylar issues. It could be any
of those, possibly more, but we are getting there and
trying the most often to fail points to hopefully get
to the real issue asap.

#4017718 Atari 800 xl acting strange.

Posted by 1050 on Sun Apr 29, 2018 3:04 PM

it wont stop a program

And that depends on the program where it can be shut off
by design. BASIC has the break key working and will error
out when pressed while running something simple like

10 PRINT "hello world"
20 GOTO 10

RUN that and then press the break key. If it doesn't stop
that program then your break key really doesn't work.

#4012838 Atari 8-bits Memory Inventory

Posted by 1050 on Sun Apr 22, 2018 10:49 AM

Can I vote 4x for 576k RAM ?!? Somehow we must beat those 1088k Atari owners, heck the poll shows even more 1088k owners than 64k owners...

Ahah! :) I kinda figured that attitude would show up and
even be the underlying reason for such a poll in the first
place. Rumor has it that ramdisks are useless above x
size and not much is done with them anyway. And x varies
according to non ramdisk user in the first place. And not
much is done with them anyway. Did I mention that not much
is done with them anyway?

People can say similar as much as they want, but without a
full meg available to me, my hands are tied behind my
back. Like typing with the nose, it's not happening here.
Give me meg or give me death.

#4005550 Indus GT U7/U8

Posted by 1050 on Wed Apr 11, 2018 2:12 AM

Thanks BillC, I never even noticed that there could
be either FDC chip installed here. So that might be
one missing U7 if he has a 2797 instead. :)

The other then is on 04-0110-X10 top board shown as
distributed logic gates of the 7416 hex inverter
also called U7.

Now wondering what WART is short for as this slowly
makes more sense. Always wanted one of these and never
ran across one.
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#4005344 Indus GT spares?

Posted by 1050 on Tue Apr 10, 2018 6:53 PM

The baking soda and super glue trick?

#4005341 Indus GT U7/U8

Posted by 1050 on Tue Apr 10, 2018 6:47 PM

According to these.
Attached File  Indus schem.zip   2.04MB   27 downloads

There are no twin U7s but one of them was for a
7416 hex inverter buffer/driver with open-collector
high-voltage outputs

One schematic does show a stepper motor buffer that
appears to have been optional, perhaps this is the
second open spot?

Don't have one so don't know a top board from a main
board. Can you sift thru these and inform us of which
schematic is for which board so I can write that info
into the file name for the next guy? TIA.
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#4001868 XEGS ROM Geometry

Posted by 1050 on Thu Apr 5, 2018 8:18 PM

Not sure it will help at all but I've found that
OS eprom speed need to be 200ns and above or they get
flaky enough to behave as if they aren't even there.
Sort of like yours? Had several OS projects fail
and then discovered this anomaly with no issues
since. No explanation for it of course.

#3999538 How to load SRC files?

Posted by 1050 on Mon Apr 2, 2018 8:57 PM

As stated previously, my assembly experience is limited but as you say there doesn't seem to be much to these sample programs.
I need to sit down with your ascii conversion and the book sometime this week and see if that sheds more light on why the SRC assembly programs on the disk were chosen: what instructional value in teaching a) assembly language techniques or b) useful info for 6502 programming (specific to working with this chip) there is/might be to the programs chosen for the book/disk.

Maybe I can shed a bit more light on it? I knew from
past experience with MAC/65 that major missing part
was missing. The I/O library, which just happens to
be in Mclaneinc's ATR. Trying to make up that code
from the book/disk offerings would quickly escalate
into insanity in my opinion. All these would then
be .include files in the manner in which MAC/65 does
it. I know there are assemblers that don't go there
in that spelled out manner and this one sounds like
one of those perhaps. They have strong points and
problems perhaps doing it this way, while it allows
MAC/65 to do other things it's own way too.

Once you have OS system equates and the I/O library
defined, the basic thought is you can now concentrate
on writing code for your project without having to
deal with the minutia every time you want to read
the keyboard for user input as one example.

But I find MAC/65's I/O library to be less than
ideal and I wind up using nothing of the supplied
support files. I'm not doing what they envisioned
that I would be either and that may be why I can
find little utility in those files. I'm going to have
the same opinion for another assemblers support
files especially when the major slice of the pie
just isn't there (yet).

So with that reveal maybe you can see behind my
comments so far as to the worth of this .src code?
If you are doing what they envisioned you would
be doing with this .src code, then it's good
stuff all day long. I have no doubt this assembler
has many talents and is a strong contender in
experienced hands. You just don't get praise
from junk code and many have a high opinion of it.
I'm good with that part. I'll continue to look
at it myself.

As to learning assembler I see no easy guide to
offer you. But I do get a sense that you have
a very good handle on how to fillet a fish like
this one good and proper already. It's been a
pleasure from another part of the same high
state of colorado.

#3998404 What do these DOS symbols mean?

Posted by 1050 on Sun Apr 1, 2018 3:05 PM

Yes, the symbols would be added on the fly by DOS (they are not actually on the disk directory sectors).

Beg to differ but they are, they are just not coded as
atascii such that you can see them with a sector
editor for example. But the first byte of the directory
file entry has a flag change to indicate that this
file is special. It's the flag read that can't be
made sense of by other DOS and so the file disappears
from a directory listing. Fixing the flag, shows the
file, but that doesn't enable the DOS to access the
second VTOC sector nor enable higher than 720 sector
access. You may have just opened the disk for
catastrophic damage to it's file structure by allowing
any old DOS to see those files above 720.

Any write might be the end for that disk. Reads might
be safe, but there already is DOS 2.5 that has no
issues at all with full access so why not do it that
way instead? I'm pretty sure MyDOS will fail to read
those files correctly, can't say as to others since
I'm not so fluent in those. The issue is untold bugs
with unknown consequences in code we don't know for
a fact will work. Not all DOS will work with those
'corrected' disks. That makes it a crap shoot when
there was no real need to go there.

It may be that it LOOKS good to go but at any moment
at any sector, the file being copied gets cut short.
And no clue if it's a possibility or not and how
many DOS you gonna test read only functionality with?

I went thru the pain of moving my entire library from
DOS 2.5 extended file system to MyDOS SD disks - it was
agony. But there is no real shortcut that can be trusted
to be faithful to the original file stored above sector 720.

It might be that I'm just skittish about the entire
deal, but I've dealt with ruined file structure disks
before and the nightmare is real. Especially on a disk
that contains something valuable. I'll consider it as
a neat gimmick, but I wouldn't trust that modified
disk any further than a used car salesman.

#3998319 How to load SRC files?

Posted by 1050 on Sun Apr 1, 2018 1:41 PM

Why didn't you read the PDF Mclaneinc posted?

Thanks for asking, it helps the next guy at the very least.

I plainly wasn't expecting much at that link.
I wouldn't be interested in an 800 only executable
made by the source code. It needs that part fixed and
I'm not doing that.

I assumed Fingolfin was in a cloud of confusion over
what he had. My main point was to post the source in
a more accessible manner without needing the assembler.
And show the pitfalls of doing so that often need doing
when dealing with source code - there appears to be
NO desire to be universal, each assembler's source
needs translating to another if you want to use another
assembler with that source.
Mainly to show that there is not so very much useful
here after all.

Turns out there is an assembler and instructions,
my bad. I'll go get it, don't have much luck with
assemblers from the good old days. Having one that
does something at all would be nice.

#3997225 How to load SRC files?

Posted by 1050 on Fri Mar 30, 2018 7:20 PM

One of the first projects that I got completed on
my journey to becoming a code head was the eprom
burner software printed in the Hofacker Hacker book.

There they also used illegal calls to the 800 OS
which breaks this code for XL/XE use outright. First
thing we are taught as Atari coders is to NEVER do
direct OS jumps. Apparently Hofacker never got that
memo - this is 800 only code, just like the eprom
burner would only work on the 800 with it's 3rd and
4th joystick used for the eprom burner project.

AND I found a glaring error in the code which further
insured that the project as a whole would never work.
In that book, the program code was printed as blocks
of hex code in the pages of the book so that saved
them from having to supply a physical disk. I don't
think much of either method since we don't know what
OUT LN means or does or could do.

#3997207 How to load SRC files?

Posted by 1050 on Fri Mar 30, 2018 6:58 PM

End of the day this atr is just an obligation fulfilled,
Hofacker said the book came with a disk and this is the
disk, so now you can go fish or any other thing. But
what you can't do is take Hofacker to court since the
book came with a disk as advertised.

No matter it is using some unknown word processor to
make the text .src files with that are not the usual
fare today and this needs converting to more standard
flavor for general consumption to start with.

Then there is assembler used which is unnamed in the
source code as well. Each line starts with OUT LN for
example which I take to be a Line Number routine which
is not included that I could note while I did the above
conversion to ascii so we all could see the forest for
the trees.

My take on it is horribly done with no include hints or
useful source other than it qualifies legally as source
code perhaps. I would have to replace many items if I
were to translate this source code over to MAC/65 and
at the end of the day I have saved 2 minutes using this
stuff as the starting point where it could take all day
to come up with something that works. IF I knew what that
was in the first place, and I don't.

At any rate the translated source files are zipped below
as .txt files readable on the PC. To use these with an
Atari you'll need to further translate 0D0A pair for
Atari 9Bh linefeed character and there are many programs
for doing this that run on the PC at least. They used 09h
for TAB character so I replaced those with 5 space
characters just because it makes my life easier to do it
that way. Some programs want to vomit when they hit 09h
TAB character and I have little patience when it comes to
cleaning up vomit.

So not very useful information on the disk, perhaps some
of the BASIC programs are where these were meant to be
used? NOT going there because this is really your job.
I find the files to be mostly fluff and filler, to be
ignored for the most part.

Attached File  Hofa.zip   5.7KB   20 downloads