PB100-170 memory compatibility

[Aektann]

Hi,
is it possible to expand the memory for PowerBook 100 by the memory card from PowerBook 170? It seems like both model are using 100ns PSRAM. However, I don’t want to risk plugging the RAM without asking for clearance here.

 

[mmu_man]

The other way I'd say yes, this way I'm not sure, you'd have to check the developer notes for both models, I recall they changed a pin function somewhere in the line because the ROM wasn't on the board anymore.

 

[alexGS]

My experience is that a memory module that fits the PB100 will also fit the other 100-series models. I think they all have the same connector and an 8MB upper size limit. Going the other way (from PB170 to PB100) there may be a physical size problem with fitting the wider board in the PB100, but I think it is worth a try.

 

[alexGS]

The other way I'd say yes, this way I'm not sure, you'd have to check the developer notes for both models, I recall they changed a pin function somewhere in the line because the ROM wasn't on the board anymore.

Indeed - I see what you mean
Fortunately the guidance was not to use that pin unless the expansion was to replace the system ROM (which is on board for the PB170), which seems unlikely to me. But I guess nothing is ever absolutely certain.

“♦ Note: If you are designing a RAM expansion card, you should normally consider pin 49 (/ROM.CS.EXP) as no connection, unless your expansion card includes its own ROM and it is intended to replace system ROM.”

 

[bibilit]

My experience is that a memory module that fits the PB100 will also fit the other 100-series models

I will not say that.

While they all look similar doesn't mean they are using the same board or evolution of a same board.

The PWB 100 is indeed a better version of the Macintosh Portable made by Sony, while the other models were made by Apple.

140 and 170 share the same kind of Ram expansion

160/165 and 180 are again compatible.

the 100 is one of the kind and won't fit one way or another.

 

[bibilit]

FYI

6MB Apple PowerBook 100 PurpleRAM newly made RAM memory module PSRAM | eBay

PowerBook 100.

www.ebay.com

 

[alexGS]

Fair enough, bibilit I have a 2MB board in my PB100 that has printed on the PCB “For PowerBook 100/140/145/160”, and in my other PB100, I am using another 2MB RAM board (two chips each side) that was originally from a 170 I thought, but I respect that not all boards will be compatible with all models. Mine are both 2MB, I imagine the larger boards are likely not to fit.

There is also the possibility of boards not following Apple’s guidance to ensure 16/32bit compatibility (PB100 having 16-bit RAM and the others 32-bit). I think boards originally fitted in standard configs would be compliant, but how many are standard by now, I wonder.

Thanks for the link, it is tempting to spend $79 on that 6MB expansion to get 8MB total, but I really shouldn’t I was thinking of downgrading to 6.0.8 instead…