cobracon Posted November 5, 2017 Share Posted November 5, 2017 I recently dug out my Atari 400 and fired it up. To my surprise it worked, well for about 20 seconds. A 0 appeared at the begining and end of the memo pad logo and black screened. I tore the computer down and reseeded all the chips hoping that would help. No go. I went on Ebay and order a new GTIA chip for the unit and that is where I'm at. Today I checked the voltage on the power supply and it's running 10.4 volts. My question is: Is this voltage ok? I don't want to replace the GTIA and fry it right away. Thanks Quote Link to comment Share on other sites More sharing options...
Umberto Posted November 5, 2017 Share Posted November 5, 2017 10.4 is what mine reads and works fine Quote Link to comment Share on other sites More sharing options...
cobracon Posted November 5, 2017 Author Share Posted November 5, 2017 Thank you very much. Looks like its time to dig in then. Quote Link to comment Share on other sites More sharing options...
+Nezgar Posted November 6, 2017 Share Posted November 6, 2017 (edited) Since the 400 & 800 internally rectify and regulate the 9V AC to 5V DC (and 12V DC?) maybe worth checking the output voltage of those regulators to make sure it isn't outputing too high or too low? Edit: the voltage can be measured from the joystick and SIO ports without cracking it open again Edited November 6, 2017 by Nezgar Quote Link to comment Share on other sites More sharing options...
cobracon Posted November 6, 2017 Author Share Posted November 6, 2017 Thanks for the tip. I will measure it at the sio port. Quote Link to comment Share on other sites More sharing options...
ClausB Posted November 6, 2017 Share Posted November 6, 2017 Is your 400 a horse, or a garden? 4 Quote Link to comment Share on other sites More sharing options...
1050 Posted November 6, 2017 Share Posted November 6, 2017 Woe Nelly, woe. 1 Quote Link to comment Share on other sites More sharing options...
Nukey Shay Posted November 7, 2017 Share Posted November 7, 2017 < gives Nelly a carrot Quote Link to comment Share on other sites More sharing options...
Mclaneinc Posted November 7, 2017 Share Posted November 7, 2017 Is your 400 a horse, or a garden? Could have been the word 'woah' 400 times across the screen which would indeed have made me think "WOAH" Quote Link to comment Share on other sites More sharing options...
cobracon Posted November 8, 2017 Author Share Posted November 8, 2017 It's a horse of course 1 Quote Link to comment Share on other sites More sharing options...
cobracon Posted November 8, 2017 Author Share Posted November 8, 2017 Alright I checked the voltages at the sio port and they are spot on. So I went ahead and replaced the GTIA. Now instead of a black screen, I'm getting a Green screen. What should I check next? Quote Link to comment Share on other sites More sharing options...
hunter44102 Posted November 8, 2017 Share Posted November 8, 2017 maybe check the cartridge port for damage or dust that could be shorting something. Look for bent pins on the joystick ports and SIO port. You could have a bad memory chip also. Quote Link to comment Share on other sites More sharing options...
+DrVenkman Posted November 8, 2017 Share Posted November 8, 2017 Alright I checked the voltages at the sio port and they are spot on. So I went ahead and replaced the GTIA. Now instead of a black screen, I'm getting a Green screen. What should I check next? Personally, I would check the CPU, then the OS ROM chips. Also: http://www.dictionary.com/browse/woes versus http://www.dictionary.com/browse/whoa?s=t Quote Link to comment Share on other sites More sharing options...
cobracon Posted November 8, 2017 Author Share Posted November 8, 2017 Looks like I'm just going to part it out. By the time I buy all the parts just to test it, I could buy a used working one. Quote Link to comment Share on other sites More sharing options...
ClausB Posted November 8, 2017 Share Posted November 8, 2017 Buy a used working one, swap parts until you find the bad part, replace it, and then you have two working ones. 1 Quote Link to comment Share on other sites More sharing options...
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