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Finding memory for PB 170


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I'm trying to get a PB170 of mine into shape to help me with a retro 68K dev project. I was able to replace the HD with a Stratos CF PowerMonster CF card adapter I had from waaaay back (very satisfying that). But the machine only has 2+2 = 4 MB RAM, and I need 8 to run THINK C++ 7 and the debugger. So I'm hunting for a 6 MB RAM expansion board. It seems from reading that at least some of the 1xx series RAM boards should be compatible with each other, but what's the real story? If something comes up on eBay for a PB 145, or 165, or 140, or 180, can I buy that and swap it in? 

 

I saw the post just below about 180 memory not fitting into 180C, but I think the implication was that 180C memory would work in a 180. Maybe it would work in a 170 as well? 

 

 

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21 hours ago, siliconinsider said:

I am in the process of making new memory for the powerbook 100 series. Stay tuned!


This is very interesting! Which models will you be targeting? Do you know if the 14MB limit on the 160/165/180 is defined in ROM, or just a function of the then available silicon? A PowerBook with 32MB would be awesome!

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It's a limitation over the available chip select lines. There are 8 chip select which are used to drive each 32bit bank of 4 chips, so that's a maximum of 8*4 = 32 chip of 512k = 16MB.

I am not sure why 14MB is the limit and not 16MB as there's a remaining chip select line, but it could be due to the ROM. The PowerBook use Pseudo-static RAM, a technology that's not widely used due to the high cost compared to DRAM and I'm not aware of any other chip than 512k. The powerbook is hardwired to use those 512k chips and nothing else.

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On 4/19/2021 at 1:35 PM, Frobozz said:

I saw the post just below about 180 memory not fitting into 180C, but I think the implication was that 180C memory would work in a 180. Maybe it would work in a 170 as well? 

 

A 180c RAM card will work just fine in a 170. I ran my 170 using a 10 megabyte card from a 180c for a while before eventually getting a proper 6 megabyte board. The 150 is the only 1xx PowerBook who's RAM can't be used in the 170 (the 150 motherboard is based on the PowerBook Duo and uses Duo RAM as a result). 

 

The machine will only address up to 8 megabytes regardless of the card that's installed. But it'll fit and work without a hitch.

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I've got the most unwieldy looking third party 10MB RAM module in my PB180c; made on the cheapest thinnest PCB with an odd shape.  Doesn't work reliably, as it flexes too much and/or a trace is bad from years of use.  Sadly had to take it out and I think it's at 8MB now.

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On 4/19/2021 at 3:35 PM, siliconinsider said:

It's a limitation over the available chip select lines. There are 8 chip select which are used to drive each 32bit bank of 4 chips, so that's a maximum of 8*4 = 32 chip of 512k = 16MB.

I am not sure why 14MB is the limit and not 16MB as there's a remaining chip select line, but it could be due to the ROM. The PowerBook use Pseudo-static RAM, a technology that's not widely used due to the high cost compared to DRAM and I'm not aware of any other chip than 512k. The powerbook is hardwired to use those 512k chips and nothing else.

I have two or three small modules, around 4MB or some such, but one of them has several pads vacant. The psram chips are not identical (they are marked differently from different manufacturers), but I have wondered whether I could make a larger RAM card by combining a number of these (dissimilar) chips onto one card by desoldering/resoldering. Or would that just kill the card because the chips aren’t the same?

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A quick look at the prototype I received last week. It does not work yet, although I have followed the Apple developper manual's directions. I have a 2MB module and the chip select lines seems to be wired differently.

So I need to do some fixing, but it's coming together. If someone has a 10MB module (especially with unpopulated chip) it could help me to trace the chip select lines.

Capture d’écran 2021-04-28 à 22.11.44.png

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Some PSRAM partially populated :

4MB for 160/165/180 (10MB if fully populated) :

2017-11-21-2127.thumb.jpg.13ae7bd4008103bad4191bb9d7d8a429.jpg

2017-11-21-2128.jpg.0266014d88d6085e2c0eacd7b51fa29b.jpg

 

another :

2017-11-21-2125.thumb.jpg.bf3a51001dad5bcb8ad68e2d82748c92.jpg

2017-11-21-2126.thumb.jpg.7009bc81628f687f84366cbe88874f37.jpg

 

For 165c, 180c, PSRAM card size is different due to Cousin card.

6MB (10MB if fully populated) :

2017-12-09-2231.thumb.jpg.b456682a49a502294393089521454121.jpg

2017-12-09-2232.thumb.jpg.ab74fc9c0bf52de97adaf034a6faec5f.jpg

 

Another for PB140-170-145, with only 2MB  and 6MB (fully populated) on one side :

IMG_2953.thumb.JPG.f3b84aaaab42183f2943076967d538e2.JPG

IMG_3745.thumb.JPG.60042fa7180040dd000dc5686c29ecd5.JPG

2017-12-09-2235.thumb.jpg.0a0dccb51b75e3ab094f97579a72f13a.jpg

 

The more difficult to find is 6MB card for PowerBook 100. A small card because no place... 

I found only some with 4MB.

6MB card for PB100 (from Apple Service Module doc), not fully populated :

65781549_6MoPB100.thumb.jpg.7ddaccaea89d460ecf3a38e2f2d64de6.jpg

 

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On 4/28/2021 at 5:20 AM, siliconinsider said:

A quick look at the prototype I received last week. It does not work yet, although I have followed the Apple developper manual's directions. I have a 2MB module and the chip select lines seems to be wired differently.

So I need to do some fixing, but it's coming together. If someone has a 10MB module (especially with unpopulated chip) it could help me to trace the chip select lines.

Capture d’écran 2021-04-28 à 22.11.44.png

 

Tried to upgrade a 6 MB to 10MB module earlier last year and failed. Couldn't figure the select lines either. 

Blurry memory here, but there was something on Developer Notes though : there is a specific line for 6MB+ modules. This changes the way select lines are used and the bank size. Idea was that some modules could be used for both P140/145/170 and P160/165/180.

 

Pretty sure your 2MB module is for P140/145/170 and the other one is for P160/165/180.

 

Edit:

Check PowerBook_160_180.pdf (PowerBoook 180 Developer Note):

- RAM Expansion Slot Page 7

- /FASTRAM Page 25

- RAM Chip Selects page 26

 

From memory, /FASTRAM DOES change how the select lines are used.

 

Let me find this damn module so I can post pictures…

 

Edited by demik
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I found the problem, I swapped UL and LU, and messed up one of the address line connection.

Now that I have this working I'll be able to roll out some final PCBs. I also have a 10MB module.

Thanks all for helping with photos!

 

This module is compatible with 16but bus, so it should work in the PowerBook 100. I hope it physically fit in the machine. I do have a PowerBook 100 but it's buried in my stuff...

 

IMG_0618s.jpg

Edited by siliconinsider
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On 4/30/2021 at 5:57 AM, siliconinsider said:

So yes it will not physically fit in a PowerBook 100. It would require an entire redesign with a new shape, which is quite challenging as the RAM chips are really packed tight. I have never seen such a 6MB module, so thanks for posting a photo!

Yes, you need a small PSRAM for the PowerBook 100.
See the photo (with 2MB in place) :

PB100-PSRAM.jpg.e4766f72776d29209299083e7972d25c.jpg

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On 4/30/2021 at 5:57 AM, siliconinsider said:

So yes it will not physically fit in a PowerBook 100. It would require an entire redesign with a new shape, which is quite challenging as the RAM chips are really packed tight. I have never seen such a 6MB module, so thanks for posting a photo!

 

On 5/3/2021 at 12:26 AM, siliconinsider said:

Working on the 100 and 165c/180c

Very impressive :-)

If you make some for PowerBook 100, I am ready to order ;-)

The other models in my collection are already at their maximum.

If you need more info on the 100 series models, I have them all and working.

Edited by gpbonneau
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  • 1 month later...

Big achievement, today I received my prototype boards for the PowerBook 100 modules, and they work first try!

Considering the super convoluted PCB routing it has involved, I am shocked and thrilled.

 

I have tested it in my 145B, so while it is still possible that something with the chip select lines are not OK, I'll send it to Hypertalking for a final test.

I have a PowerBook 100 but it's buried behind tons of stuff and I can't access it :(

 

Since I have quite a few prototype board that work, I'll now ramp up with a production PCB order and source the PSRAM. It's coming!

 

 

 

 

IMG_1043s.jpg

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1 minute ago, siliconinsider said:

Big achievement, today I received my prototype boards for the PowerBook 100 modules, and they work first try!

Considering the super convoluted PCB routing it has involved, I am shocked and thrilled.

 

Oh, very well done :D

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On 6/18/2021 at 2:16 PM, AbelVincze said:

Hi... I have a powerbook 165 which i want to use for dev, but i accidentally ordered a memory upgrade for the 165c. I wonder if i swap the female connector to a male connector, will it work in the pb165?

PSRAM card for the 165 and the 165c uses the same connector (female on the PSRAM card).

Only the shape of the PSRAM card is different (there is less space on the 165c, same on the 180c, due to the Cousin card).

165 :

1008105013_2017-11-21-2127copie.jpg.55b720cad81e67ce4c4b51fca9e140cb.jpg

 

165c  :                                                                                               an other for 165c :

515193897_2017-12-09-2229copie.jpg.b67c3324734cfef9d8bf968cfe93f4e7.jpg                    1405610322_2017-12-09-2231copie.jpg.e62dfeb412b7702ec7154867bb633709.jpg   

 

I think the memory you bought is actually the 165c Cousin card, on which there are 8 PSRAM (4MB base in the 165c/180c) and the 2 Apple ROMs. This card only works in the 165c and 180c. The connector is not the same in the PSRAM card.

IMG_7769.jpg.dc2067f8b74c57ef49b69350f540217a.jpg

 

PSRAM card and Cousin card on the 165c/180c :

IMG_3166.JPG.2e69ed955c2295930a1568f662e4e827.JPG

 

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