candle Posted December 31, 2009 Share Posted December 31, 2009 Hello everyone, Happy New Year I've bought myself Atari MEGA 1 recently, and decided to do something creative with it Here are the results: For start, we need to desolder old RAM chips - its not an easy task, since all of them are SMT chips - You could probably cut them out, but this will be a point of no return I use HOT AIR SMD REWORK soldering station After desoldering the chips, old solder remains on SMD pads, we need to get rid of it, because it will prevent us from soldering new chips properly For this i recommend using solder wick Soldering of new chips is not that hard as it might seem, just use fine tip solder iron, and precisly place the chip on pads before soldering it - there is verry little margin for error here Throught the PCB we need to drill a hole (or use one of existing ones) and conduct the wire from pin #5 of first RAM chip (U40) to pin #64 of MMU (U30) What we need to do now, is to connect all pin #5 of RAM chips together forming MA9 line that makes this upgrade complete required chips can be found on 30 pin SIMM modules, the same as we use for 8bit Atari memory upgrades Candle Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/ Share on other sites More sharing options...
tjlazer Posted January 2, 2010 Share Posted January 2, 2010 Very nice work! If I lived close I would have you do an upgrade to my Mega 2. Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1910722 Share on other sites More sharing options...
candle Posted January 2, 2010 Author Share Posted January 2, 2010 move then Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1910773 Share on other sites More sharing options...
Lynxman Posted January 10, 2010 Share Posted January 10, 2010 I've bought myself Atari MEGA 1 recently, and decided to do something creative with it This is very nice, i have done the same with 2 or 3 Mega 1. But there are some Mega 1 which are made with DIL-DRAM-chips... You made very good pictures, no problem for other people to do the same. What we need to do now, is to connect all pin #5 of RAM chips together forming MA9 line that makes this upgrade complete Do you use a 68 Ohm resistor? Atari uses this resistors in the MAD-lines to the memory chips. required chips can be found on 30 pin SIMM modules, the same as we use for 8bit Atari memory upgrades And this chips can also be found at Lynxman. New, unused, best quality (Mitsubishi or Motorola 60/70ns) for 2 € (8chips for only 2€!) + shipping. So there is no need to desolder the chips. Very nice work! If I lived close I would have you do an upgrade to my Mega 2. Was there ever a Mega 2 with SMD-memory-chips? Lynxman Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1917170 Share on other sites More sharing options...
candle Posted January 10, 2010 Author Share Posted January 10, 2010 i haven't noticed any terminators on MA lines, perhaps i was not paying enought attention never the less upgrade runs perfectly stable Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1917187 Share on other sites More sharing options...
Lynxman Posted January 12, 2010 Share Posted January 12, 2010 i haven't noticed any terminators on MA lines, perhaps i was not paying enought attention never the less upgrade runs perfectly stable You can see this Resistors in your first pic. Starting with R52. Anyway, your Mega is working. Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1918555 Share on other sites More sharing options...
candle Posted January 12, 2010 Author Share Posted January 12, 2010 and i can also see they are rated for 33R Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1918595 Share on other sites More sharing options...
Lynxman Posted January 16, 2010 Share Posted January 16, 2010 and i can also see they are rated for 33R OK, you are right. I think the 68R was used for /RAS and /CAS. Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-1920984 Share on other sites More sharing options...
qq1975b Posted February 24, 2015 Share Posted February 24, 2015 So...was the 68R needed? or only replacing the DRAM chips and linking them as described is OK? Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3184764 Share on other sites More sharing options...
guus.assmann Posted February 24, 2015 Share Posted February 24, 2015 For RA9 a 33 Ohm resistor is needed. This will reduce spike signals when accessing the chips. So less noise and more reliable operation. BG/ Guus Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3184872 Share on other sites More sharing options...
exxosuk Posted February 24, 2015 Share Posted February 24, 2015 Nice work I don't suppose you could post a high-res top view of the motherboard ? I am working on some MEGA related problems and not seen the SMT RAM version of that board yet Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3184919 Share on other sites More sharing options...
Tillek Posted February 25, 2015 Share Posted February 25, 2015 Just out of curiosity, did this take it to 4mb, or something else? Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3185456 Share on other sites More sharing options...
qq1975b Posted February 25, 2015 Share Posted February 25, 2015 4 MB Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3185458 Share on other sites More sharing options...
santosp Posted January 6, 2018 Share Posted January 6, 2018 Nice work I don't suppose you could post a high-res top view of the motherboard ? I am working on some MEGA related problems and not seen the SMT RAM version of that board yet Original TC514256AJ-10, which replaced with TMS44400DJ-70 Quote Link to comment https://forums.atariage.com/topic/155706-atari-mega-1-ram-upgrade/#findComment-3928879 Share on other sites More sharing options...
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