I used the sequence which tested the memory, and returned the following over several iterations
*RAM ZP 0 0 0 0 0 0 0 1
*RAM ZP 0 0 0 1 0 0 0 0
*RAM ZP 0 1 0 0 0 0 0 0
Does anyone have a source for replacement ram chips?
Anonymous
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Have I stumped the community with this one?
The 80 col/RGB card I have uses 4264-15's. I've seen ones with 4264-20's as well.
Typically I use Jameco.com or Digikey.com for most stuff but a quick search did not pull those up at either site.
Questcomp currently has the same MT4264-15 ICs that are on the card I have (they say 67 left in stock)
Try This Link and see if that's what you are looking for.
Zan
By the way, findchips.com came up with several possible sources. I have bought from questcomp before which is why I posted that link.
I did not price compare or aything so you may have better luck elsewhere.
Zan
There are M A N Y on eBay
like this
251391724000
or
251666089003
or
251706413153
(removed)
Thanks for the replies I have purchased the replacement chips from the info you provided
Quest Components is Golden!!!
Where I work, we have sourced older components from them, with excellent results.. ( I am the Maintainer and Repairer of the Older Products that were made. Supporting older products will always get you good will with Current Customers, as well as Future Customers... )
I would buy from them again. And most likely will.
MarkO
I could not find a datasheet on the particular chips I had originally on my apple iie. They were the Texas Instruments TMS4164-15NLJ.
One of the chips was bad so I ordered an 80 column card that I knew had 8 memory chips on it. I installed the chips on my iie and it works fine now.
But now I am stuck on an 80 column card and only 7 chips.
The card has two part numbers on it:
820-0067-B and 607-0103.
Do the listings on questcomp (MT4264-15) or (TMS4164-15NL) match the chips that will work with this memory card?
So the chips arrived today, not having a reference for which one is 1 and which one is 8, i did a best guess and swapped two chips.
The computer showed the error MMU over and over
and once in a while showed 00010000 not knowing which one was 5 i decided to pull one chip and reinsert the board.
with the one chip mising, i get the beep and the System OK.
Now im confused. is the 80 column card borked in my computer?
can I introduce one chip at a time into it or must all the banks be occupied?
Jordan
I got it
Staring at the card with the 8 chips to the left
8 7
6 5
4 3
2 1
mission accomplished