_The Doctor__ Posted January 23, 2018 Share Posted January 23, 2018 (edited) mt4264? -??either the intec has it's own refresh or it's using the stealth/hidden refresh or they are usingMT4264N-2,MT4264N-15,MT4264N-3,MT4264N-20 might have been a 1 and a 5 in that line as well are all special case ram chips that do NOT use pin1 these special case ram chips were used in mutli purpose ram/io cards primarily for gaming or serial/buffers etc... wide range of uses down to nibble modes and refresh varieties... that all I got... ymmv Edited January 23, 2018 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
ACML Posted January 23, 2018 Author Share Posted January 23, 2018 mt4264? -?? either the intec has it's own refresh or it's using the stealth/hidden refresh or they are using MT4264N-2, MT4264N-15, MT4264N-3, MT4264N-20 might have been a 1 and a 5 in that line as well are all special case ram chips that do NOT use pin1 these special case ram chips were used in mutli purpose ram/io cards primarily for gaming or serial/buffers etc... wide range of uses down to nibble modes and refresh varieties... that all I got... ymmv Mine say MT4264-4 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 23, 2018 Share Posted January 23, 2018 (edited) The only other scribbling I find is on normal 4264's in order to use them in some instance ...4164 or 4264 64 K x 1 DRAM. +---+--+---+ N/C |1 +--+ 16| GND D |2 15| !CAS !WE |3 14| Q!RAS |4 4164 13| A6 A0 |5 4264 12| A3 A2 |6 11| A4 A1 |7 10| A5 VCC |8 9| A7 +----------+ If you need one of the 4164 chips and don't have one you can also use a 41256 instead. You have to solder a short piece of wire between pins 1 and 16 of that chip (these are the pins just left and right of the alignment notch on the chip). This mod will make the chip look just like a '64 chip to the system. Edited January 23, 2018 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
ClausB Posted January 24, 2018 Share Posted January 24, 2018 (edited) Well, 41256s have 256 cycles anyway. The board I saw had Fujitsu MB8264 DRAMs with 128 cycles, so maybe there were other versions. Could you photograph your board, front and back? Edited January 24, 2018 by ClausB Quote Link to comment Share on other sites More sharing options...
ACML Posted January 24, 2018 Author Share Posted January 24, 2018 (edited) Well, 41256s have 256 cycles anyway. The board I saw had Fujitsu MB8264 DRAMs with 128 cycles, so maybe there were other versions. Could you photograph your board, front and back? Here's the photos. The board is called an Intec 6448 (see back). Note some ICs on front have Intec stencil. The second one is a little different, but also uses 4264-4 64x1 chips Edited January 24, 2018 by ACML 1 Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 24, 2018 Share Posted January 24, 2018 (edited) these are -4 special case ram, but I'd still give the refresh a close look, it may do refresh lower 128 the refresh upper 128 on the board itself Edited January 24, 2018 by _The Doctor__ Quote Link to comment Share on other sites More sharing options...
ClausB Posted January 25, 2018 Share Posted January 25, 2018 Yes, quite different from the one I saw. The 74LS393 chip is an 8-bit counter, so it's likely these boards do the 256-cycle refresh themselves. 1 Quote Link to comment Share on other sites More sharing options...
ACML Posted January 25, 2018 Author Share Posted January 25, 2018 Yes, quite different from the one I saw. The 74LS393 chip is an 8-bit counter, so it's likely these boards do the 256-cycle refresh themselves. What's still odd to me is that I replaced all eight MT4264-4s with TI TMS4164NL-15s and the machine would not boot at all. The TMS4164NL-15 is a 256 cycle refresh chip. Do you think the "-4" means 400ns? Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 25, 2018 Share Posted January 25, 2018 Clause do you still have your gear? Perhaps a closer look analyzing what's happening on the board? Quote Link to comment Share on other sites More sharing options...
ClausB Posted January 25, 2018 Share Posted January 25, 2018 Maybe one of the TMS chips is bad? The MT datasheet I have does not show a -4. Yes I have have some gear. Why? Quote Link to comment Share on other sites More sharing options...
_The Doctor__ Posted January 25, 2018 Share Posted January 25, 2018 It just looks different than I remember a MM6448, and I was thinking, If you could see it in operation how it was working exactly. Drifting off topic I guess, All I can say is, try the memory, pin one lifted, and then pin one in..... shouldn't hurt anything. Quote Link to comment Share on other sites More sharing options...
ACML Posted January 25, 2018 Author Share Posted January 25, 2018 It just looks different than I remember a MM6448, and I was thinking, If you could see it in operation how it was working exactly. Drifting off topic I guess, All I can say is, try the memory, pin one lifted, and then pin one in..... shouldn't hurt anything. Just realized that the first one is a 6448, but the second one is a 6464. Both are 48K for a 400. Quote Link to comment Share on other sites More sharing options...
1050 Posted January 25, 2018 Share Posted January 25, 2018 Searching for datasheet for MT4264-4 which was futile, found this instead http://www.minuszerodegrees.net/memory/ram.htm which may help somebody and I've never seen it before. Sorry if someone posted it earlier. Do you think the "-4" means 400ns? No, but I don't know what it does mean, the examples of -3 exist but without datasheets to tell us exactly, -3 appears to be for 200ns and several other makers use it the same way but none show -4. Quote Link to comment Share on other sites More sharing options...
Like us on Facebook
Follow us on Twitter
AtariAge on Instagram
Watch us on YouTube
Chat on Discord
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.