question on //c memory replacements

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ericF's picture
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question on //c memory replacements

Has anyone had luck replacing the Micron MT4264 DRAM in a //c with 4164 variants? The //e I have has Siemens 4164 soldered to the motherboard. There is some information that the 4264 is back compatible with 4164, but not the reverse. However, the //e's and //c's should be similar in their memory handling and likely do not use the unique features of the 4264 (whatever they may be - page addressing?)

merci d'avance,
eric F

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Re: question on //c memory replacements

any 4164 variant of similar speed should just work.

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Re: question on //c memory replacements

A follow up: I had three bad 4264 chips. In the first bank, chips 0 and 3, and chip 4 in the second bank. The self-test would sometimes report back GLU error, other times "RAM ZP 0 0 0 0 0 0 0 1". After replacing the first, I had "RAM 0 0 0 0 1 0 0 0," then "*RAM 0 0 0 1 0 0 0 0". I replaced these with Toshiba 150ns 4164's and all is well.

This was my family's old //c. It's nice to have it working again.

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Re: question on //c memory replacements

hey thats nice you got the //c working! invest if you dont already have with the following:

1. Raspberry Pi (with A2cloud software)
2. two usb/serial adapters with null cables

with those components connected to the //c you now have mass storage capability, and internet access!

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Re: question on //c memory replacements

I had the same problem with a iie. It would not turn on or it would turn on but showing only garbage on the screen. I ran the same diagnostics described in this thread. I replaced one bad chip with another brand but I was concerned with using different branded chips together could cause system instability so I instinctively came up with the idea to buy a iie 64k 80 column card - the kind that has 8 ram chips in a row. The motherboard does not have ram chips soldered onto the board and neither does the 80 column card so replacing the ram chips was a breeze and now the motherboard is ready to be sold. It passes all diagnostic checks now.

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