Search CMOS RAM chips

Dear Friends,

I'm trying to get 2 CMOS static RAM chips 256 x 4 (300ns or better) reference HM6561 from Intersil or another vendor. Could you help me to get these?

MAny thanks for your help. All the bests. Pierre-Francois f5bqp

Reply to
"Pierre-François (f5bqp_pfm)"
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These devices are long obsolete.

You can use the CMOS RAM 5101 in place of these all you have to do is=20 invert the chip select (as I recall). Pin-for-pin the same otherwise.=20 You may have to use a CMOS inverter and tie it to the battery supply for =

the memory retention to work correctly - you will need to read the spec=20 sheets on both chips to figure that out...

At least there are still al lot of 5101s left.

--=20 (Please post followups or tech enquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)

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"Old pinballers never die, they just flip out."

Reply to
John Robertson

Hi John,

Thanks for the info, I'll look at it.

All the bests.

pf

Reply to
=?ISO-8859-1?Q?=22Pierre-Fran=

"Pierre-François (f5bqp_pfm)" Inscribed thus:

I might have some kicking about. Give me a chance to check.

--
Best Regards:
                          Baron.
Reply to
Baron

Le 28/02/2011 20:15, Baron a écrit :

Thanks Baron.

All the bests pf

Reply to
=?UTF-8?B?IlBpZXJyZS1GcmFuw6dv

ence=20

Any static RAM is going to be better than those, larger capacity and=20 faster speed. Unless this is to replace RAM in some existing equipment, one might as well start with higher density cmos RAM, if you don't need=20 the extra space just set the unneeded address lines to a stable state.

Even if this is to replace RAM in existing equipment, it might be easier=20 to build some sort of adapter to plug in than try to find such old RAM. In 1976 it was a great way to get some RAM with the RCA Cosmac Elf, but even then it was a pretty small amount of RAM.

I don't know what's available these days, but there was a whole wave of CMOS RAM that had the same basic pinouts as standard ROM. Or when this sort of question came up even some years back, someone suggested cache RAM off an older motherboard, it was something like 24pin package but a narrow DIP.

Michael

Reply to
Michael Black

,

=20

r=20

These are 22 pin midwide ICs. The difference between 5101s and these is=20 minor, one select line needs to be inverted. I assumed this is for=20 existing board and it would be too much trouble to make up a kludge=20 socket to replace the two 6561s...

Still one could fool around with a 2116LP or similar and accomplish the=20 same results.

John :-#)#

--=20 (Please post followups or tech enquiries to the newsgroup) John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)

formatting link
"Old pinballers never die, they just flip out."

Reply to
John Robertson

Hi Michael,

Thanks for your reply and your ideas, I've looked at that but the space between the boards is so small that I cannot use the piggyback technique.

pf

Reply to
=?ISO-8859-1?Q?=22Pierre-Fran=

Hi John,

As I replied to Michael, the space between the boards is so small that building a piggyback module is impossible. However I guess I've found these ICs, I'm waiting for two of these. I'll need to find one or two others as spare just in case...

pf

Reply to
=?ISO-8859-1?Q?=22Pierre-Fran=

How about Ebay:

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Reply to
JW

Le 01/03/2011 11:12, JW a écrit :

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Yes thanks, I got two of these, they where not here yesterday.

pf

Reply to
=?ISO-8859-1?Q?=22Pierre-Fran=

"Pierre-François (f5bqp_pfm)" Inscribed thus:

The ones I have are HM6564 ! Sorry. :-( If I come across any I'll let you know.

--
Best Regards:
                          Baron.
Reply to
Baron

Le 02/03/2011 20:50, Baron a écrit :

Thanks for your reply Baron.

All the bests pf

Reply to
=?UTF-8?B?IlBpZXJyZS1GcmFuw6dv

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