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Member Since 24 May 2007
OFFLINE Last Active Today, 5:12 PM

#4101897 Atari 800 XL burning power adapters

Posted by 1050 on Wed Aug 29, 2018 9:41 PM

Keep your money guys, use it to buy needed stuff with.

Like a voltmeter. Be sure to test it without the computer
connected first. You are looking for 5 volts where 7 or
so means the power supply is a RAM killing machine. Check
both power supplies or all you have for that matter.
Connect good 5 volt supply to computer and turn it on to
measure again, you still need 5 volts and if you don't
have it then the computer is drawing too many amps.
To be continued...

Move your #3 coil to an easy to work on spot and move that
coil to #3 spot. Start it up, if the miss follows the
coil, buy a new coil. If it stays on #3 buy a spark
plug and spark plugs wires if that is applicable in your
particular case. Still no joy you need to do a compression
test on #3, today's engines should be over 100 PSI with
185 being near new condition. To be continued...

#4098018 Second XEGS Repair

Posted by 1050 on Thu Aug 23, 2018 9:00 PM

GTIA pin 17 will make 12 volt (IIRC) so if that's it
then nothing to really worry about there. Phase 1 clock
is voltage doubler pumped to provide that signal and
it is required. You sure you are not on AC voltage

Doesn't that indicate that they're working?

You are certainly assuming wrong, logic probe tells us
there is activity but not if that is going in or
coming out or what it should be. If you had a dead ROM
I would hope all the support chips would be trying to
talk to it in an effort to wake it up. Dead doesn't
mean all signals enter the twilight zone and cease to
exist, it means instead they are mostly ignored by the
vacant party of concern.

These XEGS ROMs are known to lay right down and die.
You can only prove a positive by swapping with a known
good ROM and that doesn't fix it outright.

I don't believe STELLA is a chip found here. Please call
it GTIA if you meant GTIA instead.

XL/XE schematics are almost identical as to device number.
C42 is circled but I can't find it in XL/XE nor do I
know if XEGS schematic number match XL/XE scheme as tightly
as does XL to XE. Atarimania does not have XEGS in
SAMS which means all we have is Sobola Schematic, is that

#4090986 PBR Print Buffer Routine (anyone ever seen one?)

Posted by 1050 on Mon Aug 13, 2018 6:09 PM

Very much better but still in error due to repeated
segments of same information. BUT the emulator is not
prepared for a 2K file at all and it's very likely this
form is the only one that would fly there anyway.

Here is the 2K version for those wanting to duplicate
it exactly. I already tested it by adding it to itself
three more times and then testing that file against your
file for no differences encountered report from MS-DOS
file compare program. Nicely done.

Attached File  pbr2k.zip   1.02KB   12 downloads

#4090676 Replacing the 130XE MMU amd EMMU with GAL chips

Posted by 1050 on Mon Aug 13, 2018 10:31 AM

Except you haven't fully tested it yet grasshopper...

I thought so too, until I started a complex printing
project and where I have done it before and knew it
like the back of my hand, it would not start with the
GAL MMU in place. Suspicious, this might be the issue
a swap showed it was the case and the printing began.

They do work is the take away, but there can be timing
issues even with the best effort to match original and
exactly why my GAL failed to function in only this
mode is beyond my capabilities to find out about.
Just because it doesn't immediately take you to the
self test doesn't mean all is perfect. Wish I had a
conclusion to this story too but I don't.

#4082115 Trouble with FTDI for SIO2PC

Posted by 1050 on Mon Jul 30, 2018 6:30 AM

Every time I see FTDI I think of the clone chip troubles.

Just over a year ago, FTDI, manufacturers of the most popular USB to serial conversion chip on the market, released an update to their drivers that bricked FTDI clones. Copies of FTDI chips abound in the world of cheap consumer electronics, and if youve bought an Arduino for $3 from a random online seller from China, you probably have one of these fake chips somewhere in your personal stash of electronics.

After a year, we have the latest update to FTDI gate. Instead of bricking fake chips, the latest FTDI drivers will inject garbage data into a circuit. Connecting a fake FTDI serial chip to a computer running the latest Windows driver will output NON GENUINE DEVICE FOUND!, an undocumented functionality that may break some products.

The above dated 2016 and found in the wild with a
simple search on FTDI clone. Unless you use a linux
box there still appears to be no resolution to the
issue. Windows plus FTDI cloned chips is a brick.

Since your symptom is a brick and this issue is still
alive, I have no hopes of a solution. I also see no
solutions anytime I look this issue up online. Just
a lot of hate and hot air.

#4066263 1050 drive issue

Posted by 1050 on Mon Jul 9, 2018 4:01 AM

Glad you took the roughing up as well as you did, no
harm no foul, I now know what DOS is being used, thanks.

Ok, the repeating busy light is supposed to be a bad
6532 RIOT chip but often they are changed out and the
symptom remains. Best if you had a working donor to
supply the 6532, but they are on eBay as R6532P.

#4065405 1050 drive issue

Posted by 1050 on Sun Jul 8, 2018 2:58 AM

Post 32 and still no DOS report.

Looking like you'll be a year before we can beat enough
info out of you to provide any help at all. Error numbers
come from the DOS installed so it's important to know the
DOS used. Especially useful for odd error numbers like 174
first reported.

Error 138 is Device Does Not Respond, that means DOS can't
see it, nor can the OS. First thing to do is buy some DeOxit
contact cleaner and wet the drive select switches from the side
with the cover off. Then work both of them at least twenty times
while still wet. Let it dry and work them again twenty times.

Now select them for drive one position.

drive select 1050.JPG

Any Joy?

#4056210 Anyone know how to burn a single standard OS ROM?

Posted by 1050 on Sun Jun 24, 2018 5:02 PM

Depends, might be normal behavior for a fast eprom
and thus it's still good.

For OS work, I've found that one wants to use a
200ns or slower eprom, faster ones will act wonky
when they do fine as a cartridge rom. Can't fathom
why either, just reporting how it is here.

#4040624 Atari 800xl repair log / bad video output

Posted by 1050 on Sun Jun 3, 2018 7:48 AM

Ages old B&C Atari vendor's eBay storefront, pretty
much can't go wrong with those rubber feet. Same ones
Atari used. They are Atari NOS.

#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.
  • slx likes this

#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.