I recently puchased a used Laserjet 4 Plus (the 12 ppm printer) which I want to upgrade with 16MB simms. From past experience with a standard Laserjet 4, I thought 72 pin FPM simms with parity would work fine. I have used generic 8MB simms w/parity which worked fine and even installed a couple of spares into the LJ 4 Plus which recognized the simms without a problem.
The LJ4 plus will also accept 16MB simms so I purchased some used Micron simms, 72 pin FPM with parity thinking that would do the trick. Wrong. The printer never gets past the "self test", giving a memory error message. Someone moved the cheese.
The Micron simms have the following model chip numbers MT4LC4M4B1DJ-6 which translates to:
4 -Dram
L - 3.3 Volt
C - CMOS
4M4 - 4 Meg X 4
B1 - 2K Refresh
DJ - ?? Think it mean FPM
6 - 60 ns
and there are also also four 4Mb drams on the simm for parity.
Although I haven't put the simms on a memory tester, they are probably good so must assume that HP changed the spec.
So the question is, what type of memory does a Laserjet 4 Plus use? Is it also generic memory or is it a proprietary design? Seems odd that the 8MB w/parity would work but not the 16MB.
Thanks for the help.
The LJ4 plus will also accept 16MB simms so I purchased some used Micron simms, 72 pin FPM with parity thinking that would do the trick. Wrong. The printer never gets past the "self test", giving a memory error message. Someone moved the cheese.
The Micron simms have the following model chip numbers MT4LC4M4B1DJ-6 which translates to:
4 -Dram
L - 3.3 Volt
C - CMOS
4M4 - 4 Meg X 4
B1 - 2K Refresh
DJ - ?? Think it mean FPM
6 - 60 ns
and there are also also four 4Mb drams on the simm for parity.
Although I haven't put the simms on a memory tester, they are probably good so must assume that HP changed the spec.
So the question is, what type of memory does a Laserjet 4 Plus use? Is it also generic memory or is it a proprietary design? Seems odd that the 8MB w/parity would work but not the 16MB.
Thanks for the help.
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