HP Laserjet ..again....

From: Geoff Reed <geoffr_at_zipcon.net>
Date: Sat Sep 18 20:52:31 2004

At 02:17 PM 9/18/2004, you wrote:
>As I stated earlier, I have cannibalized three HP laserjet series II
>printers. In looking over the parts recovered I find that I have three
>(3) totally different memory boards.
>The first is populated with small chips on BOTH sides of the board with a
>total of 128 soldered in chips that appear from their part numbers to be
>256K memory chips, That is the number 256 appears within the part
>number. Now I don't know how wide the buss is but I am assuming 8 bits
>because of its age. If so this board is a 4 Megabyte memory board.

um, that sounds probable...

>The second is only half populated with 16 soldered in chips on one side
>that have the number 1000 in their part number so I am assuming they are
>1meg chips and using the afore mentioned logic I come up with a
>2Megabyte memory board.

yes, that's a 2meg board using 1 megabit chips

>The third is fully populated with 32 socketed chips with the number 1000
>in their part number and that works out to a 4 Megabyte memory board.

yes, that is a 4 meg board.

>Is my logic sound?
>Do I have two 4 meg boards and a 2 meg board?
>What is the largest memory board the Series 2 could hold?

  4 megabyte

>I am assuming that the socketed memory is best because it is easily
>repaired, but are there any problems with the socketed memory having bad
>contacts after time?

the biggest problem I've had with laserjet boards is the PALs and GALs they
used on some boards (HP and aftermarket) for addressing failing over time :(
Received on Sat Sep 18 2004 - 20:52:31 BST

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