68kMLA Classic Interface
This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.
| Click here to select a new forum. | ||||||
| PB 2400c ram | ||||||
| Posted by: MacUp72 on 2024-05-11 04:32:02 just dropped in..wow, this fella is tiny, interesting..feels very sturdy, nice build quality. 180Mhz model, english 8.6. install, came with an Buffalo Air Station 11Mbit Wifi card and the external floppy drive..the power brick is tiny!  have to open it soon to look for the pram battery, I wonder if I can use one of my old SDRAM sticks in it. these are pc100, came from a Lombard etc. , as far as I read the original was EDO Ram.  | ||||||
| Posted by: Byrd on 2024-05-11 05:44:17 They’re great laptops. The RAM is tricky - you need specific modules for the 2400c, standard EDO RAM does not work. 32/64 MB modules can be found usually on Japanese auction sites, the 96MB modules are very rare specific to the model. | ||||||
| Posted by: MacUp72 on 2024-05-11 10:21:59 So what happens if I stick one 64Mb stick in it, wont it be detected or gets it fried? | ||||||
| Posted by: Byrd on 2024-05-11 15:46:40 It won’t be detected | ||||||
| Posted by: 3lectr1cPPC on 2024-05-12 16:04:14 Lower capacity standard EDO RAM should actually be detected. I'm fairly certain 32MB is the limit, and anything over that needs the rare custom RAM. | ||||||
| Posted by: MacUp72 on 2024-05-13 04:13:58 ok I did a dis- and reassembly of the machine because I wanted to take a look at the actual RAM thats installed, remove the pram battery and replace the HDD with a SD/IDE card. I guess the encircled two yellow cables are those for the PCMCA/CardBus mod? ( this model is the 180Mhz model)   interesting, theres Viking RAM in there, and yeah, this does not look like a PC100 type  removal of the mainboard and daugtherboard    for the reassembly you have to disassemble everthing and reseat the daugtherboard.  luckily the PRAM didn't leak very much, theres only one tiny bit of corrosion on the connector, cleaned up with IPA  luckily nothing got broken and it started right of the SD install. I wonder where the clock crystal is located, maybe I'll swap it with a faster one as in the 3400c. | ||||||
| Posted by: MacUp72 on 2024-05-13 05:11:31 its confusing, EDO Ram basically belongs to DRAM, all 144pin, not compatible with newer synchronous SDRAM, ok. EDO came in different packages, some ( as mine above) with 28 pin footprint, others with 32, but all EDO Ram run on 5V, not 3,3V. so, maybe these 32pin EDO can run in the 2400c?  | ||||||
| Posted by: MacUp72 on 2024-05-16 01:42:59 ok, little update on the RAM, I bought an IBM branded, 64MB, EDO SO-DIMM 144-pin 60ns 3.3v stick, after boot in 8.1 only half of it, 32MB are being recognized..ok, better that before, but still strange. ( I cleaned the contacts three times). I asked the seller and he just went with the recommendation of the standard Apple page that only 32MB are supported. That would mean even if you have correct period correct EDO RAM, like in the ThinkPad 380/380E (May 1997), like mine, it still would recognize only 32MB. Only Apple branded special RAM would be recogized 64MB or higher, these modules must have a special addressed RAM design.  here some screenshots of 64MB sticks featured in different YT videos you can see these in fact have 50 pins chips on them ( not the older EDO chips with 28)     the infamous 96MB RAM, 64MB down+32MB on top of it ( distributed on both sides)  | ||||||
Posted by: mg.man on 2024-05-16 01:58:08Only Apple branded special RAM would be recogized 64MB or higherCould it be the way the memory is "arranged" (accessed)? The IBM DIMM states 8Mx64:  Maybe the "Apple" memory is 16Mx32? | ||||||
| Posted by: 3lectr1cPPC on 2024-05-16 04:39:30 Only 32MB being recognized is consistent with what I’ve heard. I believe the pinout of the higher capacity 2400 modules is different. | ||||||
Posted by: MacUp72 on 2024-05-16 10:48:53Could it be the way the memory is "arranged" (accessed)? The IBM DIMM states 8Mx64:..we need one of those RAM sticks to do an examination🥷 | ||||||
| Posted by: Fizzbinn on 2024-05-16 11:16:15 There is some info on this isn the PB 2400 and 3400 developer notes. There are copies here among other places. PowerBook Information & Resource ArchiveAn information and resource archive dedicated to Apple's Macintosh PowerBook
Looks like they are saying the PB 2400 SoDIMM is mostly a repacking of the 3400 RAM expansion module. That last line seems pretty odd, perhaps what makes these PB 2400 SoDIMMs unlike other/generic 144-pin EDO SoDIMMs | ||||||
| Posted by: MacUp72 on 2024-05-16 13:20:10 thats a lot of valuable info ..reading through the two PDF I wonder how you would compare the form factor of a 3400c RAM expansion module ( has only one side populated) with that of a SO-DIMM 😳..and the connectors    maybe a new interesting community challenge..as there is obviously a demand for these RAM, wordwide..especially the 96 MB one... 👍👨🎓 | ||||||
Posted by: ThisDoesNotCompute on 2024-05-16 15:38:33IIRC this is the key part -- the story I've heard is that they accidentally swapped those lines on the motherboard, so 64+ MB modules needing to be "special" wasn't intentional. | ||||||
| Posted by: 3lectr1cPPC on 2024-05-16 15:46:24 What I wonder when is: would it be possible to swap the lines back on the motherboard? | ||||||
| Posted by: MacUp72 on 2024-05-17 09:01:54 found a funny site about modding a SO DIMM for the 2400.. use google translate.. 
《今だから明かせる秘密》PowerBook 2400cとNUpowr G3 for 2400の開発秘話10（最終話） | Jacob's Ladder日本IBMのエンジニアから96MBメモリーモジュールを特別に見せてもらいました。通常は64MBまでしか認識しないのですが、特別に追加で32MBを認識させることが出来るということでした。であればぜひともNewerでもこの96MBモジュールを製造・販売すべきだと提案しましたが却下されてしまいました。それならば他社で作ろう。
macmem.com
| ||||||
Posted by: macuserman on 2024-05-17 10:51:58found a funny site about modding a SO DIMM for the 2400..That's a fun site, he also wrote an article about the development of the ultra rare 400mhz G3 card for the 2400. https://macmem-com.translate.goog/w..._sl=ja&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wapp Also I fixed your link so that it is already translated. 😉 | ||||||
| 1 | ||||||