urzu117

Hello, I recently acquired a ti-99/4a in somewhat decent condition for not much money, but I'm having an issue with it. On boot, it goes to the software select screen. I don't have a cart, so it only gives me the option to go into TI BASIC (as expected). The problem is, I get to BASIC for about a fraction of a second before the computer soft reboots on its own and then locks up upon the software select screen. Any ideas on where to look for the source of the problem?

That it does. So primary worry eliminated, I have a 64k machine with no bad RAM. Not gonna bother upgrading it, since it's looking to be a dealer installed upgrade, so I'd rather keep it that way for aesthetic and historical reasons. Thanks for the help everyone.

Okay, so I ran PRINT FRE(0), and got back 37k free. According to the board's amount of 4416s, they should be around 64k. I know that the OS and BASIC take up some of the RAM, but that much?

Also both the card and the serial on the 600XL have a year of '83, it might be a dealer upgrade?

Well mystery partially solved. Turns out I lied and made up the whole thing (not really, just a case of bad memory and mixing up two different companies because both have the term "engineering" in their name). Here's the photos I promised. As plainly seen, it's not Applied Engineering, it's a company called BOT Engineering.

Well I figured this is probably the best place to ask. I got an atari 600xl a year and a bit ago, didn't come with a power supply and didn't get one till about 6 months ago. I got some cart games and software to play around with and when I was messing with the self-test, the RAM test kept going for a long time, up to 48 blocks of RAM were tested. Concerned that there was a bad RAM chip, I opened up the machine and discovered a massive Applied Engineering RAM daughter card installed over where the stock RAM would've been. I thought Applied Engineering only produced upgrades for the Apple II, Mac and Amiga machines? I looked up the data sheet for the RAM chip type on the board, and it turns out there's a bunch of 4K chips that add up to 64K total. Can someone shed some light and tell me what the hell have I got? An apple II upgrade that was modified for a 600XL, or an actual AE stock product sold for the 600XL? Will post pics later when I crack the machine open again.