Atari 800 screen normal.....then goes to crap!!

[imacav8r]

Hello.

had a dead machine that needed a Pokey, got that fixed. Now machine boots to normal notepad and ready prompt with Basic cart installed.

it works fine.

When i try to load a game or anything using graphics the screen goes bad. like it cant get vertical hold, just garbled crap.

trying fuji net i get the bar graph fuji net screen clear as a bell. as soon as it goes to the next screen where you supposedly pick wifi source, that is the same garbled mess.

going to GR.2 and plotting a single pixel.... that pixel is a % symbol.

using the SDrive-Max and selecting the D0 menu gives the options table but the characters are all junk. correct placement, but random characters.

loading games from SDrive-max results in the same garbled screen once the game is loaded.

i have:

changed the CPU card which changes cpu, antic, ctia/gtia

changed the rom card

removed memory leaving only 16K.

basic installed/removed 

nothing makes any difference.

 

Help!

[xrbrevin]

junk chars usually mean defective antic. try reseating the IC and also check the integrity of it's socket if you have a multimeter

if you have a spare machine to try it in - see if the problem migrates with it

[imacav8r]

9 minutes ago, xrbrevin said:

junk chars usually mean defective antic. try reseating the IC and also check the integrity of it's socket if you have a multimeter

if you have a spare machine to try it in - see if the problem migrates with it

dont have a second machine, but i have tried 2 different Antic chips. same issue.

[Paul Westphal]

Switch out the first ram card that’s behind the ROM card. It could be bad. 

[+videofx]

Move the 16K ram card and test in the other 2 slots, if that doesn't help then try a different 16k card and test all 3 slots

[imacav8r]

7 minutes ago, videofx said:

Move the 16K ram card and test in the other 2 slots, if that doesn't help then try a different 16k card and test all 3 slots

the only thing i have is a 16K proper Atari ram card, and a 32K ram card from Intec Peripherals Corp. i have tried it with only the 16K card.

16K card in any other slot does not even boot

32K card in first slot does not work does not even boot

4116 chips from IPC card installed on the Atari 16K card does not even boot

 

back to the 16K card with OEM 4116 chips in first slot again works but gives original problem.

[Beeblebrox]

@imacav8r just in case remember the first slot at the very front is the Os rom card slot so don't plug any rams cards at in that. Just try the os rom board in the front and them one other card in one of the other three remaining slots behind it. 

[imacav8r]

17 minutes ago, Beeblebrox said:

@imacav8r just in case remember the first slot at the very front is the Os rom card slot so don't plug any rams cards at in that. Just try the os rom board in the front and them one other card in one of the other three remaining slots behind it. 

Ha!

yes sir. The front slot is rom only. Never had a different card in that slot other than rom. 

[Beeblebrox]

Cool.. Was just checking just incase.. 

[imacav8r]

18 minutes ago, Beeblebrox said:

Cool.. Was just checking just incase.. 

Thanks for sure!

What do you think about moving forward with the incognito install? if it is memory this should fix it.

All normal basic things are OK, but there is still an audio hum and i dont get the beeping during a S-drive max load...like a normal disk beep load.

[Beeblebrox]

Sure,  why not at this stage. 

 

So again see my blog in my signature.  It also links to the 2 x fjc vids on the install which I recommend you watch.  As I mentioned my blog guide compliments it. 

 

I did another incognito install on Wednesday. 

 

Remind me is this an ntsc or pal 800?

 

 

Edited September 17, 2022 by Beeblebrox

[imacav8r]

7 minutes ago, Beeblebrox said:

Sure,  why not at this stage. 

 

So again see my blog in my signature.  It also links to the 2 x fjc vids on the install which I recommend you watch.  As I mentioned my blog guide compliments it. 

 

I did another incognito install on Wednesday. 

 

Remind me is this an ntsc or pal 800?

It is a ‘DOM’ ntsc machine. 
any thoughts on my audio?

 

NTSC. 
Any thoughts on the audio?

Edited September 17, 2022 by imacav8r

[Beeblebrox]

8 minutes ago, imacav8r said:

NTSC. 
Any thoughts on the audio?

Re audio.  In what context? (Only skim read the thread so may have missed or forgotten something). 

 

The audio is taken from the din out.  Recommended you get a decent S-video cable from hercules workshop in Canada.. It's double shielded and you get great output.  As part of the fjc incognito install you improve the video a little also by replacing some resistors. 

[_The Doctor__]

I am surprised no one told this fellow to take the BASIC cartridge out when using disks etc. Since that will give the display issues just like when not holding the option key down on an XL. Other than that it's time to sort through the ram chips.

Edited February 1, 2023 by _The Doctor__