Atari self-test memory

[Gunstar]

I had a recent mishap with a 1200XL and I have been salvaging upgrades from it and transfering them to another 1200XL. Anyway, I've got most of it done, but I'm having problems with the memory. I've currently got a Rambo XL board and 256K memory chips. But I'm attempting to check the base memory anyway, so I started with the self-test memory program. At first it crashed after a while, locked up the computer, I swapped some chips in and out and tried again, the next time it ran through the whole memory test and repeated, but at the moment I can't remember how many horizontal rows of 16 blocks there are supposed to be. It's showing three rows now, which is 48 blocks. I thought I remembered at least 4 rows (64 blocks) on the XL (I don't recall if the 130XE I used to own just checked the first 64K or not and how many rows it showed in the test). Can anyone comfirm how many rows there are supposed to be, and maybe a quick explanation if it's supposed to be 4 rows, how I can have only 48K working. I mean, shouldn't the memory test at least report any bad memory? Aren't the blocks supposed to show up as RED instead of GREEN if they arn't working? Or what? Is it just 3 rows?

Edited September 29, 2011 by Gunstar

[sloopy]

it only shows 48 blocks, for the 48k... the rest of ram is under the hardware i/o and ROM... for both XL and XE. However on Rev3 of the OS, it will recognize the ext ram of the 130XE and test that in another row of 4 large (hopefully) green rectangles...

 

sloopy.

[Gunstar]

Thanks! So at least I know the self-test is working as well as at least the first 48K. I've been having some problems with programs, graphical glitches and stuff, all of which started after I installed the Rambo XL, but I think the ones I've tried so far were 64K programs. Also, I have been trying an extended memory test program from Satantronic, and it's saying I don't currently have any extended memory even though I have all the 256K chips installed. Bad memory somewhere (I HOPE it's the memory, and not the Rambo board!). I guess I'm going to have to test each chip individually. I have 512K worth (16 chips), becuase I had upgraded the Rambo XL to 512K (but I figured one step at a time and make sure the base rambo XL is working before boosting it again), so hopefully I can at least find 8 working ones out of them all and at least get the 256K working again until I can get more chips.

 

So, the rev. 3 XE OS tests extended memory? How about extended memory without the Freddie chip? I have the APE WARP+ 32-n-1 board, so I think I have that OS on it...I have a rev. C, is that it?

Edited September 29, 2011 by Gunstar

[WizWor]

When I was in school, I worked at a department store that sold Atari computers. One day I came in to find twenty 800XLs piled up at the service desk -- "They're all defective," I heard as I walked in the door. This was before google, so it was real work to find out why only 48K tested on 64k machines...memories...

[Gunstar]

OH, MY HOLY USER!

[Gunstar]

Well, right now, only the 400/800/1200XL and Warp+ OS's will even install from my 32-in-1, so I'm unable to test the Rev 3/C self-test. The APE board was working good before I installed the rambo, so I think it's still a memory thing, though I don't know enough to know why these would be the only OS's willing to work right now. I'm just messing around to see what does work right now, I don't feel like testing memory chips at the moment.

[sloopy]

if xram doesnt see your rambo, then something is probably not hooked up right...

 

 

sloopy.

[thorfdbg]

The so-called "memory test" of the self test is mainly a hoax anyhow. First of all, it doesn't really test all memory - the first K is not tested, the block is just drawn right away, and the RAM under the selftest is neither tested, just the blocks are drawn after some delay. The RAM under the ROM is neither tested. And second, the RAM test is not very thorough either, it just writes data and immediately reads it back. Defective RAM tends however to "forget" its contents after a couple of cycles, and this is not tested for either.

[sloopy]

The so-called "memory test" of the self test is mainly a hoax anyhow. First of all, it doesn't really test all memory - the first K is not tested, the block is just drawn right away, and the RAM under the selftest is neither tested, just the blocks are drawn after some delay. The RAM under the ROM is neither tested. And second, the RAM test is not very thorough either, it just writes data and immediately reads it back. Defective RAM tends however to "forget" its contents after a couple of cycles, and this is not tested for either.

 

i will agree, a machine that will pass the memory self test isnt definitely good, as it may have still have mem or other issues... but a machine that wont pass the memory self test is definitely having issues, in mem or elsewhere...

 

when used properly, it can be a effective tool for step 1 diagnostics...

 

sloopy.

[Rybags]

Graphical glitches might be the old "Phase 2" timing problem. Also, I've read there are some RAM extensions, especially the old homebrews, that can experience lag when switching banks, which could also cause graphical glitches.

 

You can get the Phase 2 problem without the RAM actually being "bad" in any way, and the machine can otherwise be 100% stable, ie no unexplained crashes/lockups.

[Gunstar]

It could be a missing connection on the Rambo. On the 1200XL the Rambo uses either 3 or 4 contact pads on it for connections, depending on the version of ANTIC that is being used. I think I may need to hook up that line for this 1200 motherboard. The problem was I was swapping Antics in and out for testing at one point and I don't know which version is the original now. Right now I have a PAL Antic installed, which worked fine on the other motherboard with 3 connections, so I figured it would be the same on this one since I'm using the same Antic, but maybe a different rev. motherboard is the thing, and not the Antic itself regarding these 4 connection points on the Rambo for 120XL? In the Rambo manual it goes by the Antic chip installed to distinguish, not motherboard revisions...

Edited September 29, 2011 by Gunstar

[Gunstar]

Just checked motherboard revisions and they are both 13A anyhow. I probably just have a bad connection somewhere.

[sloopy]

the issue is the ANTIC itself, there are two different revisions of it, having nothing to do with the motherboard in the A8... any ANTIC will work in any stock A8, except the 130XE, it needs the different revision ANTIC...

 

sloopy.