Re: Question about PET DRAM

From: Gabriele Bozzi (
Date: 2005-12-09 13:34:27

Here is an interesting posting:

****** Attached posting ******

There were several makers that sported an xx15 type where the normal 16Kx1
dram was an xx16.  What these were, generally but not in all cases, were
products of a die shrink that resulted in a shorter refresh interval.  That
was certainly the case with the MOSTEK 4115's.  Those worked famously well in
applications like the Apple][ which was a big seller at the time.

****** End attached posting ***

So, it seems to be a pin-compatible 4116.. I guess a 400ns item  from the
part number you mention (which is not unusual with the double nature of
"phi" clocking of the 6502".
I am not a PET expert but imho the design of this machine did not allow use
of esotheric parts (different pin-count etc.).
I guess good old 4116s (provided access-speed copes) should do.


On 12/8/05, Bo Zimmerman <> wrote:
> Hello all... I recently got a CBM 2016-N that appears to be working fine.
> It reports the appropriate 16k at startup and everything.  My surprise can
> when I popped the case.  Inside I found that all 16 ram banks were filled,
> as on a 32k machine.
> My first thought was that it was an upgraded 2016 which SHOULD be
> reporting
> 32k, but has a bad chip.  But first I needed to make sure that those two
> rows of dram really represent 32, so I looked up the part number
> (MK4115p-40) and found nothing.  The 2001N schematics show that those
> banks
> should have 4116 chips, which are 16k by 1s.
> Can anyone help me out on what a 4115 is?  And whether 16 of those bad
> boys
> makes 16k or 32?
> - Bo
>        Message was sent through the cbm-hackers mailing list

Gabriele Bozzi
Beveren - Belgie

A: Maybe because some people are too annoyed by top-posting.
Q: Why do I not get an answer to my question(s)?
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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