Re: Apple II memory expansion card

[et472@FreeNet.Carleton.CA (Michael Black)]

"M. Pender" (mpender@hotmail.com) writes:
> On 1/6/04 3:48 PM, in article btf6uq$5e5$1@freenet9.carleton.ca, "Michael
> Black" <et472@FreeNet.Carleton.CA> wrote:
> 
>> And nowadays, the level of what's being tossed out has progressed beyond
>> 286's with loads of 256K rams.  I upgraded my 200MHz pentium from 64megs
>> to 96megs because I found a pentium (minus the hard drive or else I likely
>> would have brought the whole thing home) in the garbage last spring
>> and it had to 16meg SIMMSs.  Indeed, around the same time I found some
>> smaller density SIMMs, that filled out the used HP laserjet I bought cheap
>> a while later.
> 
> What kind of memory do HP laserjets take?  I have an HP Laserjet 6P with
> only 2 Megs in it, but I have lots of different types of chips, SIMMs and
> DIMMs around.  If I knew what goes into it I might be able to add some
> memory to it.
> 
For the 4P, it was just standard 72pin SIMMs.  I don't know if that
follows for the whole line, but a quick search suggests it is.

One of the odd things is I did a search at the time, and someone
had once posted detailed instructions on "modifying" standard SIMMs
so they'd work in the printers.  But when I actually looked up
what he was doing, he was simply wiring in the lines on the connector
for telling the computer the SIMM's speed or size.  The SIMMs I had 
had those pins wired properly, and I'm not sure under what circumstances
they would not be wired, since it is a standard part of the pinout.
I was expecting some weird setup so HP could be the only source of
memory.

Perhaps there are some issues about the density of the actual RAM
ICs on the SIMM, but then it's likely to give flakey operation rather
than a failure.  

I believe the printers do not use parity, but then if you do have
parity SIMMs, the printer will simply ignore the extra bit.

I can't remember, if I did uncover it, how much memory the 4P will
take. Given that it doesn't need much memory beyond the soldered
in memory to handle anything it can (I'm not even sure 2megs was
all that limiting, but I did have the memory), you might as
well just use small SIMMs.  I only put in 1 4meg.

   Michael