Atari 800xl Ram Repair

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Atari 800xl Ram Repair

Postby ATC on Sat Apr 10, 2010 9:55 pm

I got a surprise the other night when I got home from work, my mum had found an old fountain console and an atari 800xl for $5!

I managed to get the fountain working nicely but the atari is failing its ram test, I have opened it up and checked everything out (it all looks good) and reseated all the chips but it didn't improve the ram test at all.

So I was wondering how I would go about finding replacement ram or if it is even possible as I would really love to get it going again.
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Re: Atari 800xl Ram Repair

Postby tezza on Sat Apr 10, 2010 11:52 pm

Nathan, It is certainly doable. A source of RAM chips will be the biggest problem.

do you know what kind of RAM chips they are . 4164s? Are they socketed or would you need to desolder them?

Lastly, do you have a technical or service manual.
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Re: Atari 800xl Ram Repair

Postby ATC on Sun Apr 11, 2010 12:32 am

Hi Terry,

Thanks for your reply, I will have to open it up again and check the ram type.

The chips are socketed so they wont need desoldering.

I have 5 books/booklets that came with the atari but not a service manual - 2 books on basic, an owners guide, reference guide and a manual for the atari program recorder which also came with it along with a lot of cassettes :)
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Re: Atari 800xl Ram Repair

Postby ATC on Sun Apr 11, 2010 12:50 am

Ok I just opened the atari up again printed on the ram is: 4264-15
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Re: Atari 800xl Ram Repair

Postby tezza on Sun Apr 11, 2010 9:27 am

Hmm..

Ok, first off it's interesting that the RAM is socketed. In my experience this is unusual. By the time the Atari 800Xl came along almost all home computers had their RAM soldered in (I need to check my own Atari 800XL...perhaps it's an exception with these ones). Anyway, if it is socketed that's good news for you! It might also indicate the RAM has been repaired before. Has it been repaired properly and were the right ICs used might be a question to ask?

I'm not familar with the 4264 DRAM chip. 4164's are more common for this vintage of machine, but maybe the Atari XL 800 used them. 4264 and 4164 ICs might even be interchangable...I don't know. Sometime today if I get a chance I'll whip the top off my own 800XL and let you know what's there.

Getting a replacement IC might be tricky, especially if you need a 4264. I've used this USA firm in the URL below in the past. They have quite a few RAM chips but not a 4264
http://www.arcadecomponents.com/memory.html . Also, shipping is expensive and takes a while. It's really only viable if you have a number of components you want to get.

A good strategy for a replacement component is to look for old battered and broken unts on trademe that go for a few bucks. These are a good source of components and will probably be cheaper than getting a single IC in from overseas. Desoldering is usually necessary of course. If the case is wrecked sometimes the board is still ok, so you can just substitute it.

Anyway, I'll take a look in my own machine and get back to you. If anyone else wants to contribute into this thread, feel free.
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Re: Atari 800xl Ram Repair

Postby tezza on Sun Apr 11, 2010 5:16 pm

Nathan,

As chance would have it, I also have (or at least had up till today) an Atari 800XL with a RAM problem. It's a junk board which I had stored away for parts. Anyway, it indeed had 4264 RAM ICs the same as yours. However, unlike yours, the RAM is soldered in.

I didn't have any 4264 RAM lying around but I did have a few spare 4164 ICs. After browsing around on a web a bit, I read enough to figure a 4164 might at least be compatible enough to identify the offending IC, if not replace it entirely. I identified the faulty IC by simply piggybacking the 4164 chip over the 4264 ones. Once located, I clipped the faulty one out, soldered in a socket and inserted a 4164 IC. It SEEMS to work...at least the machine boots up to BASIC and seems to be able to run BASIC programs OK.

However, I think the jury is still out on 4164/4264 compatibiliy for the Atari 800XL. I put the question to some of my friends on the (International) Vintage Computer Forums. You can see what they said and follow the thread yourself here:
http://www.vintage-computer.com/vcforum ... -with-4164

Anyway, hope this helps with your own repair. 4164 ICs are quite common in early/mid 80s computers and (although I haven't looked) there may be a few NZ sources of these ICs.

Any New Zealander's reading this know of a source of 4164s? ..or even better still...sources of 4264s?

Tez
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