HP21 uses same RAM chip as HP25?

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HP21 uses same RAM chip as HP25?

05-21-2019, 04:28 AM

Post: #2

Didier Lachieze Offline

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RE: HP21 uses same RAM chip as HP25?

(05-21-2019 01:53 AM)calc-calcs Wrote: I was wondering if the HP21 uses the same RAM chip (HP PN 1820-1564 or AMI/Mostek MK6220N).

You'll find here a reference table about the chips used in the HP calculators.
According to this table the RAM chip 1820-1564 is used in the HP 22, 25, 91.

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Messages In This Thread

HP21 uses same RAM chip as HP25? - calc-calcs - 05-21-2019, 01:53 AM

RE: HP21 uses same RAM chip as HP25? - Didier Lachieze - 05-21-2019 04:28 AM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-21-2019, 11:14 AM

RE: HP21 uses same RAM chip as HP25? - Didier Lachieze - 05-21-2019, 11:56 AM

RE: HP21 uses same RAM chip as HP25? - vassilisprevelakis - 05-22-2019, 08:50 PM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-21-2019, 12:52 PM

RE: HP21 uses same RAM chip as HP25? - jebem - 05-21-2019, 07:37 PM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-22-2019, 02:18 AM

RE: HP21 uses same RAM chip as HP25? - Geoff Quickfall - 05-22-2019, 03:12 AM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-22-2019, 03:36 AM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-22-2019, 05:31 PM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-22-2019, 08:30 PM

RE: HP21 uses same RAM chip as HP25? - jebem - 05-23-2019, 03:09 AM

RE: HP21 uses same RAM chip as HP25? - Zaphod - 05-24-2019, 06:08 AM

RE: HP21 uses same RAM chip as HP25? - calc-calcs - 05-23-2019, 12:20 PM

Anyone have a 1820-1382 Cathode Driver or donor HP25/HP21? - calc-calcs - 06-28-2019, 04:32 PM

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