PB3400 + PB3500 "Kanga" RAM changability

[Byrd]

Hi,

I received my PB 3500/Kanga G3 Powerbook the other day, and set out fixing it up with a new HD and general spruce up, it came with 5GB HD and 64MB RAM (32 + 32MB)

I also have a Powerbook 3400 with 144MB RAM (16MB + 128MB), and thought I'd be able to put the 128MB stick into the Kanga - it looks exactly the same and fits in both machines. However, while the 32MB stick works in both machines, the 128MB only works in the 3400 (the Kanga boots with the 128MB stick but it is not detected).

Googling around it appears my suspicions were correct; not all modules 64MB and above from a 3400 work in a Kanga, but there are conflicting reports about this; some have said the RAM works fine in either machine, others no.

Does anyone have any experience with this, or can offer suggestions?

Thanks

JB

 

[Byrd]

Great news - I was able to hack my 3400 128MB module to work on the Kanga!

It surprised me that the 3400 128MB module didn't work - considering that the 32MB Apple module worked fine on both machines, and both modules had 60ns rated chips. Apart from the Kanga having a G3 inside, the only major difference between the two models is that the 3400 has a 40Mhz bus, and the Kanga 50Mhz. When the 128MB module was installed in the Kanga, it would either not detect at all, or every now and then Mac OS would report a memory error at startup; then it would freeze within a couple of minutes.

So it got me thinking that perhaps the 128MB module was running at a slightly faster latency to work at optimal bandwidth in the 40Mhz bus 3400, and the latency needed to be slightly reduced for compatibility @ 50Mhz bus in the Kanga. Looking at the 128MB part - which is very generic - two solder pads R8 and R9 (with zero K resistors - or shorts) suggested to me that something could be adjusted. I didn't have much to lose, considering it was a bit of a downgrade to keep the 64MB Kanga over the 144MB 3400 - so I switched both resistors to their other position on the PCB (well, I switched one by one but the same issues occured - needed to relocate both in the end).

And, success! 160MB fully detected and rock solid on the Kanga. I can now attempt to install OS X onto this machine - which will be a sight to see.

Pictures below detail the location of resistors R8 and R9 (this is the "after" picture, ie. for Kanga compatibility), and a Mac OS screenshot.





Hopefully others can use this information to max out their Kanga with more common 3400 RAM!

JB

 

[tmtomh]

Wow - very impressive! Well done.

 

[Byrd]

I was very lucky, but it goes to show how proprietary RAM modules - must have some "play" in them to be mass produced for slightly different computers. So that's another unique thing about the Kanga: last Apple laptop to use overpriced, dicky proprietary RAM modules! All Macs after this used standard off-the-shelf RAM modules.

I'm not sure if other Mac notebooks (below the Kanga) have comparible compatibility problems like this - I don't think so ... most models have had the same bus speed, regardless of CPU frequency, unless anyone recalls otherwise!

I've been hammering the Kanga for many hours now, and it's not missed a beat.

JB

 

[Mars478]

Wow I believe this is one of those posts that should be backed up and archived.