Are you sure the 6550 is dead? (was: Mos Technology RAM wanted)

<> Are these single voltage or multiple? 4k? 22pin? sounds like the <> semi-4600 and NEC D410 parts, a 4k pseudostatic 200ns cycle and access <> under 120ns. I've got a rat load of upd410s. The moto part number <> doesn't compute though. < <uPD410 is 18-pin 0.3" width, 4k x 1, with one ~CE line (the MOS Technology <MCS6550 has 2 ~CS and 2 CS lines and it's 0.4" wide). I can't find any <data on a 4600 but I assume it's similar. Oh, you shouldn't ahve done that... ;) First off I worked for NEC Micro during 79-84 time frame... hawking memories, micros and peripherals (mostly I82xx parts) as a product engineer. uPD410 .4" 22pin three voltage 4Kx1, seperate din and dout, CE and CS/ three voltage pseudostatic. replaces Semi-4200 and 4402, fastest version to 80ns access. (it was a screamer for 1978). uPD411 .4" 22pin three voltage 4Kx1, seperate din and dout, CE and CS/ three voltage dynamic. replaces ti4060, intel 2107, fastest version to 200ns Tce access. same pinout as 410. FYI, altair 88-4MCD boards were so poor I pulled the TMS4060 static and used uPD410s to make them static, one cut to disable refresh. Very reliable after that! uPD 414, .3" 4kx1 dynamic upd 416 .3 16kx1 dynamic, industry standard 2101 .4 22pin static 256x4 (5101 is the cmos part) 2102 .3 16pin static seperate IO 1kx1 2111 .3 18 pin static common io 256x4 2114 .3 18 pin 1kx4 static, common io 2147 .3 18pin 4kx4 static, seperate IO 45ns 2149 .3 18 pin 1kx4 static common io (2114) 45ns 2167 .3 20 pin 16kx1 static, 55ns 4104 .3 18pin 4kx1 pseudo static seperate io CE/ (-5 85ns Tacc, 180ns Tcy) uPD421 .4 22pin 1kx8, same as two 2114s logically, (-5 85ns) 443/6508 .3 16 pin static CMOS 1kx1 444/6514 .3 18 pin static cmos 1kx4 (like 2114 in cmos) 445 .6 24pin static cmos 2kx8 with CE2 and CE1/ industry pintout 1 446 .6 24pin static cmos 2kx8 industry pinout 2 449 .6 24pin static cmos 2kx8 industry pinout 3 4016 .6 24 pin static cmos 2kx8 6116 pinout Most of those were industry standard with part numbering differnces. Be glad I didn't pull down my hard cover NEC catalogs. <If you're asking about the 6550 I'm looking for, yes it is single 5V rail, <but it's 1k x 4 and it's not Motorola. In fact, I'm fairly sure no-one bu <MOS Technology made them. If I knew pinout I could find an industry part that would work save for pinout or package. Allison