Identifying Machine for DEC Memory

Antonio Carlini a.carlini at
Wed Apr 1 10:31:30 CDT 2020

> On Wed, 1 Apr 2020 at 16:13, Rob Jarratt <robert.jarratt at> wrote:
>> This is the listing:

My VLC has a number of memory modules but they do not have any DEC part 
number on them at all.

The board has "PC72N-9GG" and "JAPAN MH1M36ADJ-8" printed on it.

One side has 8 chips each marked M5M44400AJ 221SK1K-7. Note that unlike 
the photo, there is no "horizontal" chip in the middle.

The other side has four chips each marked M5M41000BJ 224GE04-8. (I think 
it's four ... I've just put the machine back :-))

A nearby DECdirect has:

MS40-BA: VLC 8MB upgrade

MS44L-BA: VS4000-60 8MB upgrade

MS44-DA: VS4000-60 32MB upgrade

MS44L-BC: VS4000-90 16MB upgrade

MS44-DC: VS4000-90 64MB upgrade

So even that doesn't help (since you really want the 2-5-2 part number, 
as that's what you'll usually find on the module).

I did have a quick hunt on the net for IPBs for any of these systems, 
but with no luck. manx shows a few service manuals but they had the MS4x 


Antonio Carlini
antonio at

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