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Powerbook 540c Resurrection

reukiodo

Active member
Bolle, I have 2 extra 16MB cards (already have a 16MB card inside my 520c) with empty connector pads on the back. Could I send these to you to convert to a 32MB and play with getting 64MB or 128MB recognized?

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Iesca

Well-known member
It seems that my 540c's memory card is of a different make than the ones on display here, but I assume the principal would be the same?

The chips are labeled as:

MCM517400BT60

Motorola VQQDU9614

They also appear to use tiny SMD caps instead of resistors like Bolle's.

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EDIT: Found a data sheet on the chips in question, for the curious: https://www.datasheets360.com/part/detail/mcm517400bt60/-8453506530169633316/

 
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trag

Well-known member
Interesting.   The pin out is essentially equivalent to a single 72 pin SIMM, probably with support for two banks.

Is the connector for the RAM card still available?  Anyone have a part number for it?

How tall can the memory chips be and there still be room for the card to fit in the laptop?   In other words, must one find very low profile chips for this application?

 

Iesca

Well-known member
There is an RF shield-type metal cover that screws onto the enclosure for the ram and daughter boards, but I suppose that it's not strictly necessary. Otherwise it's quite snug in there.

There also may be a plastic arm that serves as a mounting bracket for said cover, but that can also be removed.

 
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Paralel

Well-known member
There is an RF shield-type metal cover that screws onto the enclosure for the ram and daughter boards, but I suppose that it's not strictly necessary. Otherwise it's quite snug in there.

There also may be a plastic arm that serves as a mounting bracket for said cover, but that can also be removed.


Actually, you're going to want that "RF shield-type metal cover", it is a very early example of enhancing thermal dissipation but before we reached the point of bonding the thermal dissipator to the chips using thermal adhesive or grease to make the whole process much more efficient. Your blackbird will work without it, but the daughtercards get hot enough for you to burn yourself if you touched them. With the thermal dissipator properly installed their temp is much lower.

 
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Paralel

Well-known member
From what I know of the connections on the RAM cards for the blackbirds, 12 address lines, 4 RAS/CAS, 64-bit width, means that 32 MB is the limit on size.

 
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Paralel

Well-known member
Is the connector for the RAM card still available?  Anyone have a part number for it?
I was able to find the information for the RAM card connector:

AMP, Inc. (part number 535671-6). 70-pin Metristack connector

 

kalleboo

New member
I was also able to deal with an issue with the monitor where it would occasionally flicker and/or the colors would be out of whack. I had discovered previously that squeezing the lower left side of the monitor frame would resolve this, but I was worried it was loose solder. Fortunately, as I discovered on disassembly, it was just a loose connector. And it seems to be a bit brighter, too! That may just be my imagination though. ;) 
Oh my god, thank you for this comment! My 540c display would occasionally get distorted or show jitter, and it would come and go with no real pattern (heat, etc). I tried squeezing on all the ribbon cables in the hinge assembly but never thought to squeeze the monitor itself, that cleared it right up! I'll have to disassemble the monitor itself to reseat the connector for a more permanent fix then...

IMG_6792.jpg

 
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ravuya

Active member
Sorry for bumping the thread again, but do you have a picture of the old clock/PRAM backup battery? I am wondering if it might be swelling or leaking and causing my trackpad issues.

Basically, even though my machine has been stored in a cool dry place for the last few years, the trackpad seems to really want to pull to the left, often all the way to the side of the screen, over the last couple of months. It seems to get a little better if the machine has been on for awhile, but I really don't like it when things fix themselves and I don't know why.

I haven't opened it up yet but from the Apple service source "take apart" guide it seems like the trackpad, ribbon, and control board are really close to the battery.

I assume it's NiCad?

 
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Crutch

Well-known member
I like how the fellow in that thread was able to take apart and replace the battery without opening the case by inserting tweezers in the battery slot ... which he was only able to pull off because he is a trained surgeon. That’s excellent. 

 

ravuya

Active member
Thanks for the link! It does seem like it's miles away from practically damaging the trackpad. I guess I'll see if I find anything when I get around to opening up the PowerBook.

 

nottomhanks

Well-known member
Just wanted to follow up on this, did someone verify that you could convert a 32Mb module to 64Mb? And would the 500 series recognize it, or would you need to do a few extra modifications? I have a 32Mb module with the 183Mhz 603 and it's running OS9 believe it or not!!
 

croissantking

Well-known member
Just wanted to follow up on this, did someone verify that you could convert a 32Mb module to 64Mb? And would the 500 series recognize it, or would you need to do a few extra modifications? I have a 32Mb module with the 183Mhz 603 and it's running OS9 believe it or not!!
See the post by @Paralel above - it’s been determined that 32mb is the max for the RAM card.
 

croissantking

Well-known member
I have a question: would it theoretically be possible to convert my 4Mb RAM card to a 32MB module by soldering higher-density chips on? It looks like my 512k chips are physically similar (28 pins) to the 2MB chips of a 32MB card.
 

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croissantking

Well-known member
Indeed, could the same be done to the chips on the processor card to bump it up to 8 or 16MB, for a total of 40/48mb?

I bet the same could be done to the chips on the processor card to bump it up to 8MB, for a total of 40MB.
 
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croissantking

Well-known member
OK, I've successfully converted my 4MB RAM card into a 32MB card, using a donor DIMM with compatible chips. So far, it seems stable and has passed a couple of RAM tests.

I'm actually fairly impressed that I've managed to pull this off.

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croissantking

Well-known member
Indeed, could the same be done to the chips on the processor card to bump it up to 8 or 16MB, for a total of 40/48mb?

I bet the same could be done to the chips on the processor card to bump it up to 8MB, for a total of 40MB.
To answer my own question, having looked at various SIMMs on ebay, this isn't possible.
 

Iesca

Well-known member
OK, I've successfully converted my 4MB RAM card into a 32MB card, using a donor DIMM with compatible chips. So far, it seems stable and has passed a couple of RAM tests.

I'm actually fairly impressed that I've managed to pull this off.
Congratulations on this great feat! Great to know that it's feasible and working.
 

croissantking

Well-known member
Congratulations on this great feat! Great to know that it's feasible and working.
Thank you, Iesca!

Obviously I had to do something with the chips on the other donor DIMM. My PowerBook 1400c has 40MB RAM - 16MB on one expansion module, and 8MB on the other. So today I populated all the empty solder pads and now I have the maximum of 64MB :)

Somehow it feels too easy, is this cheating?!
 

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