repetto74

Hi Guys, I have a great interest in learning basics for machine language programming on the 6502. I own a real Atari 600XL but do you think it would be easier at least at the beginning to use an emulator? I am a noob and would like to know any books or publication on how to code ML for beginners on an XL computer. Also which assembler shall I use and how to compile the source code then? I know there are some threads on this matter already but there is a lot of information and I cannot dig out what would be essential for a good start. Many thanks Rick

Hi guys. Thanks a lot for pointing to Best Electronic but sorry I did not précisé I am located in Old Europe :-) and shipping cost from California are just too high. I will try to dig it out here in the continent

Hi guys Thanks to all of your for your intervention :-). I have figured out what was wrong. The IC delay module in U13 was the faulty one. I swapped it with the one coming from another board and all was back to business ! Where can I find this chip ? It looks this is a custom made one by Atari. Ref C060472-D. :-)

Well I have a spare of all main chips with me but I have tried to swap them all and had the same problem. Now I may try again one by one and see the result.

Hi Dakidski, Problem is that I have this also with the SIO2SD disconnected...

This is the kind of crash I have after a short period of time the machine is running :

I am dumb sorry I did not swapped back the OS hip I tested on another working board (which is giving same crashes) so I was turning on without it. Anyway I had this red screen in the past sometimes together with those garbled video crashes.

Ok now the fault has moved to a worst scenario. I have a death RED screen on power up. Any idea where to check?

Hi Rybags, Thanks for your suggestions. I may start thinking also that the OS rom is somehow corrupted and unstable. The PSU may be also the problem but the thing is that even when disconnecting the SIO2SD and power recycling I will still have the problem popping out. It is like an issue popping out after a short period of time from a cold power on and once it is there I need to cool down for a while before turning the computer on again.

Hi, I started having a lot of issues when using an SIO2SD reader with a 600XL with internal 64k mod. The machine is unstable and will at any random moment freeze and display garbled colored text and characters in a rolling pattern. A power cycle will set all back to normal for a short time before starting to freeze again. Now I assume the mod is correct as the memory test is passing green with no fault detected. I cannot recall which tutorial I followed for this mod but there are maybe some more. Anyway it was posted here on Atari Age. Is there any incompatibility I may not have been aware of concerning a 64k 600xL and any sd reader ?

Hi Flashjazzcat ! Million Thanks ?

Sounds interesting :-). Is the binary available for burning it into the 16V8GAL?

I am having exactly the same problem with my 600XL!! I did the upgrade to 64k and was working really good for a few days then suddenly it started putting garbage characters on screen and then the same garbage as in the picture (with screen rolling up and down). I do have replaced both rams (already new as for used to mod the machine to 64k) with two new ones but no luck. In my case the freeze will pop up after a few minutes from cold power up. My rams are labelled 41464C-12 and were confirmed compatible. I have already swapped 64K RAMS/GTIA/ANTIC/CPU/PIA and POKEY with no luck. MMU runs very hot quickly (C061618 in U2) it may be suspicious but where I may find a replacement for it? I did not try to revert to the original 16K config, I may want to try but need then to dig out also the TTL marked 74LS51 in U16 as the leg has been broken during the mod and just a wire soldered now (cannot make this pin to contact the socket anymore). Would really like to fix this.

Again sole testing made which confirm the freeze pops up around 5 min after power up. If I leave the machine turned on then I will get this garbled screen where I can see text characters of graphic 2 mode. The ANTIC chip may have failed then. trim.3B7DB790-31AD-45B4-BA17-E282DD67DF0B.MOV

I did not precise that this is a 600xl with the 64k mod which was working properly.

Hi, My 600XL seems to randomly freeze when used with an SIO2SD reader. It can freeze while playing a game or when typing a Basic program. It does not seem to have an issue when used standalone. When freezing in Basic mode some strange patterns and characters may pop up. Here is some pictures of the failure. Note that on the RAM test I had a total freeze on first try then it went till the end but with a red square popping up. PSU is ok, output is normal. Now I made another Memory test and this time the last two blocks are red and the Mem test will crash. I noticed the crash seems to start more or less around a same amount of time after a cold power up of the machine (IC heating too much?). Now i would like to know which IC's are involved in Ram management. Which are the multiplexer positions on the board? edit : I opened the case to have a look inside and try to reseat all IC's. I noticed that one of the wiring used for the mod was in contact with a pin of one RAM chip and the insulation was melted. I may have caused a short circuit and hope I only damaged the RAM. The freeze is always popping out after a few minutes which may point to a IC malfunction due to overheat. Damned hope I did not screw the whole thing up!

Yes sorry, Commodore DOS was much more user friendly as far as I remember

OK so PSU is ok, output is normal. Now I made another Memory test and this time the last two blocks are red and the Mem test will crash. I noticed the crash seems to start more or less around a same amount of time after a cold power up of the machine (IC heating too much?). Now i would like to know which IC's are involved in Ram management. Which multiplexer? edit : I opened the case to have a look inside and try to reseat all IC's. I noticed that one of the wiring used for the mod was in contact with a pin of one RAM chip and the insulation was melted. I may have caused a short circuit and hope I only damaged the RAM. The freeze is always popping out after a few minutes which may point to a IC malfunction due to overheat. Damned hope I did not screw the whole thing up!

Hi Almerian Ok I will first check the output of The PSU. I will run the main test again to confirm the bad ram block. Those are fresh new rams installed for the mod to 64k. I doubt one is bad already. I will try to reseat all ic's also and luckily all are socketed.

Hi Almerian, Well this 600xl was working perfect until I started playing with the SIO2SD. I do not know what could be wrong with the psu. What should I check exactly? I would like also to ask if there is any trick with the SIO2SD to not power off and on continuously each time I want to load another program. I do not think that cycling continuously power is very good for the components.

Here is some pictures of the failure. Note that on the RAM test I had a total freeze on first try then it went till the end but with a red square popping up.

Hi made some testing, the RAM and ROM test is giving a green flag. I have noticed that freezes comes a few minutes after powering up the machine. Which are the chips that could be involved in this? CPU, POKEY and MMU?

Hi, My 600XL seems to randomly freeze when used with an SIO2SD reader. It can freeze while playing a game or when typing a Basic program. It does not seem to have an issue when used standalone. When freezing in Basic mode some strange patterns and characters may pop up. What this could be? In case of a bad chip is there any good chip reseller? I am in Europe. Thanks,

I have tested directly from the real 600XL machine using the SIO2SD reader and all is working now! Glad I can save my programs on a virtual disk

Hi Brenski OK that's all clear now!! It works! Sorry I was confused with the Disable Basic setting. Actually I have to enable it for the basic program to be written down and then disable it wen accessing the DOS menu :-) Thanks a lot for your help!