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65XE Self Test / Video Questions


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#1 richard13 OFFLINE  

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Posted Fri Mar 17, 2017 2:09 PM

I recently purchased a new 65XE and having just received an S-Video cable for it I decided to take it out of the box and check it out.

 

The first thing I noticed are vertical lines on the screen.  I presume this is due to the fact that I am using a modern flat-panel TV or that it is 40" which is way bigger than anything in the 1980s or a combination of the two?  Is there any way to improve on this?

 

Lacking a disk drive or SIO2SD at the moment I decided to just do the internal self test.  Everything seemed to go ok but I am a little confused...

 

Memory:  I see 3 rows of 16 blocks for a total of 48.  This computer supposedly has 64K.  Can someone verify this is normal?  What would the rationale be for  Atari to only check 48K?  Or maybe these blocks mean something different from what I think?

 

Keyboard:  The top row has some inverted characters but I can't for the life of me figure out what those are or how I would test those.  Any ideas?

 

Appreciate the help.  It's been a few decades and I'm apparently a bit rusty.

 



#2 1050 OFFLINE  

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Posted Fri Mar 17, 2017 11:21 PM

48k report is normal. And in the case where BASIC ROM is on for
good or bad reasons that amount of ram can be seen to be MIA as well.

Atari doesn't check the ram under ROM nor the under the hardware registers. It
doesn't check the ram used for the display or under the self test ROM living
at 5000h either, so in short what it does check is a simulated 48k in the
first place and it doesn't test it particularly good either. You can't look
at a block of bad ram and hunt down the contributing chip for example because
each chip contributes ONE bit of EVERY byte in the 64k stretch that there is.

So it's not much good, but it's what you got out of the box at least. These
blocks certainly do mean something different from what one is easily lead to
believe. Keyboard test might be the 1200XL function LED array and if they
were there, then I presume that they would light in order when the symbols
on the screen showed activity? Never noticed in other words and that's
just a half hearted guess. Other possibility is the HELP, START, OPTION
panel and since these are used to select the various tests, they don't
really work. But they simulate pressing them with beep, boop and screen
antics when in auto loop - all tests mode.

Self test turns out to be mostly there for entertainment value, only saving
grace is the price and availability of it. The miracle is that it can show
bad ram issues and then does become a useful tool of sorts.

Video mods can help reduce the vertical 'refresh' lines on the left of the
screen, but there is no solid solution to them that works for everyone
across the board. Some go away to a very large extent with a better video
mod applied and then some machines seem determined to ruin every attempt
to get rid of them.

#3 richard13 OFFLINE  

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Posted Sun Mar 19, 2017 2:07 PM

Thank you for your response, 1050!

 

For the memory and keyboard questions, I think this was a case of RTFM.  I remembered this computer came complete with the manual and looked there.  It explained the 48K only being counted and it also said that the top row of the on screen keyboard has some characters that don't mean anything (or something to that effect).  I see that I can check Start, Select and Option but nothing else from there.  You may be right about some of those having to do with other models.  Funny I don't remember any of that but then again, as I recall in the day, I didn't really pay much attention to these tests.  It's only interesting now since this computer is over 30 years old.  :)

 

Regarding the vertical lines, at the READY prompt, I see a vertical line on the left side but I also see vertical lines throughout the screen all the way to the right at regular intervals.   But in the Self Test they are much darker and tend to come in and out (as if there were some signal interference).  They cycle through being really obvious to barely being visible.  I see there are other threads on this subject so maybe I should poke around there.  If my experience is going to be mostly the thin lines in BASIC that's probably ok and I might not even notice it after a while but if its like the Self Test, this is going to be terrible.



#4 DrVenkman OFFLINE  

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Posted Sun Mar 19, 2017 2:13 PM

 

Regarding the vertical lines, at the READY prompt, I see a vertical line on the left side but I also see vertical lines throughout the screen all the way to the right at regular intervals.   But in the Self Test they are much darker and tend to come in and out (as if there were some signal interference).  They cycle through being really obvious to barely being visible.  I see there are other threads on this subject so maybe I should poke around there.  If my experience is going to be mostly the thin lines in BASIC that's probably ok and I might not even notice it after a while but if its like the Self Test, this is going to be terrible.

 

Those lines are caused by interference inside the machine - they are exacerbated by anything that refreshes the system DRAM - so, basically everything except a static screen. Some machines are worse than others. My 800XL with a later revision motherboard suffers from them to some extent even with a UAV board installed, but they aren't terrible. Connecting via S-video makes them almost unnoticeable. Just the nature of the crappy Atari video circuitry combined with poor isolation of the RAM from the rest of the system, electrically. 



#5 kheller2 ONLINE  

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Posted Sun Mar 19, 2017 2:35 PM

Top row should be:

Reset Start select Option F1 F2 F3 F4 h Atari Break

 

R S s O 1 2 3 4 H A B

 

I forget what the H is ... hmm

 

Google "atari xl keyboard test" and select images.  You should find a few different layouts depending on the ROM.



#6 richard13 OFFLINE  

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Posted Sun Mar 19, 2017 9:50 PM

 

Connecting via S-video makes them almost unnoticeable.

 

Hmm... but I am using an S-video cable right now and I clearly see them.  Are you saying that they are much worse without S-video?  Or do I have a lousy cable?



#7 1050 OFFLINE  

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Posted Mon Mar 20, 2017 3:22 PM

I wouldn't say 'lousy' cable even if it is a cheapy. A lot
of times each machine will output different levels on these
cables which include the composite ones too. And the
problem if you want to call it that is actually in the level
of the signal being pumped into the monitor. It's often way
too hot or too much.

JUST a S-video cable won't fix much especially if it's being
overloaded and I tend to think this one is just that. It IS a
common problem.

You will still need a video mod to get the good quality screen.
Don't expect perfection without a good deal of leg work done to
get there.
And this same cable may work there brilliantly after the video mod.
Some guys report that adding a 200 ohm resistor in series got
theirs looking perfect, others say 60 ohm. We can't know which
signal is too much or the value needed that your monitor likes
to work with. It can depend on the monitor too. I seem to
remember reading about problems with either signal using
S-video, which means you really should do your own leg work,
my memory isn't worth trusting sometimes. And I've never done a
video mod so the weight of my advice is rather light.

H - HALT and catch fire? JK - for Gods sake don't push that one.
hyphen
ATARI (inverse)
Break ??? (not kidding but still guessing)

#8 DrVenkman OFFLINE  

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Posted Mon Mar 20, 2017 3:43 PM

 

Hmm... but I am using an S-video cable right now and I clearly see them.  Are you saying that they are much worse without S-video?  Or do I have a lousy cable?

 

I'm saying that on *my particular 800XL* using a UAV Rev D video mod and a real CRT TV, I still see faint vertical lines on the left of the screen during RAM access when connected with S-video, though they are much less noticeable than the same computer with the same board using Composite. And even using composite they're not that bad *on this machine with this board installed.*

 

​As 1050 indicates, your mileage may vary. :)



#9 richard13 OFFLINE  

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Posted Wed Mar 22, 2017 12:02 PM

Thanks guys.  Much appreciated.  I had no idea this was a such a squirrelly problem!  I wonder why it wasn't an issue back in the day.



#10 TangentAudio OFFLINE  

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Posted Wed Mar 22, 2017 12:08 PM

Thanks guys.  Much appreciated.  I had no idea this was a such a squirrelly problem!  I wonder why it wasn't an issue back in the day.

 

My guess is because many of us had televisions, or at best composite monitors... And no real basis for comparison for what was good looking video.






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