Apple IIgs memory card and chip set ID

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Apple IIgs memory card and chip set ID

Hi all,
Great forum you have here. I recently dug out my old Apple IIgs system but found the CPU had been destroyed (dropped by the movers very hard by the looks of the casing)in a move 12 years back...just never noticed the crumple box end. I replaced it with a cpu from a education lot sale on Ebay. It's a rom .01 unit and was advertised as having a 1 MB memory card. When I got the computer I checked the card and it turned out to have 1mb installed on the card and two expansion chip banks still empty. Only thing written on the card is "GS 4 megabyte" at the top and "expandable to 4mb" written toward the bottom of the card. Was this an Apple card or a third party?

The chips in the two populated banks are labeled P21010-07, K144a Korea. Obviously the two banks are populated with 512kb chip sets...not 1mb, since I show 1.2mb as my ram size in the control panel. Any one know if the chips list above are still available or can I populate this board with 1mb chip sets?.....not sure what I have here?

Thanks
Jim

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sorry...

to hear that your GS got bashed up. I've had my share of stuff broken by movers. Which is why I move myself (when I can).

If I am reading things right, the P21010 is a 1 meg by 1 chip. The -07 is the speed, yours being 70ns. So a set would be 1 MB. Why yours is checking out a essentially half that, I don't know. I don't know if one of the eight in a set can fail and render the set bad, AND have the machine still boot.

GSE-Reactive seems to sell the chips you seek. I think I might have the whole card with a little bit of memory on it. I will check.

mike

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1mb

Thanks for the reply.....so I actually have a four MB board with two banks populated with 1 MB each. I got the 1.2MB size based on what I saw under Ram in the control panel. If it helps I am running under ROM 01 and GS/OS 5.0.2 plus the machine boots fine every time.

Jim

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Re: Apple IIgs memory card and chip set ID

Only thing written on the card is "GS 4 megabyte" at the top and "expandable to 4mb" written toward the bottom of the card. Was this an Apple card or a third party?

Third party - Apple signs their cards.

The chips in the two populated banks are labeled P21010-07, K144a Korea. Obviously the two banks are populated with 512kb chip sets...not 1mb, since I show 1.2mb as my ram size in the control panel.

I'm not sure I understand - are you saying the card has four banks of sockets, and two of those banks are taken up by the chips you describe? (Are there 16 vs. 8 chips ?) If so, then I wonder if there is a jumper or something you'd have to set to say how much memory there was on it. Or maybe you need to re-seat the chips?

But the on-board memory (256k-ish) of the ROM-01 and 1MiB on a card would make sense for your reported memory size.

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There are four banks total on

There are four banks total on the card. The two populated banks have eight chips each. If these are, as Mike stated based on the chip numbers, 1mb sets then I should be seeing 2.2MB as total under Ram in the control panel, right?

Jim

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Right. I'd try swapping the

Right. I'd try swapping the banks of 8. Theory 1: one bank is bad. Theory 2: the banks aren't currently filled in the right "order." If you swap all the chips and it still works, we eliminate theory 1 and can move on to 2. Apple's cards were often filled NE, NW, SE, SW when banks were laid out 2x2. How are yours laid out vs. filled?

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Will get back to you.....

Just getting ready to leave work....not that I was actually working Smile but here bumming free advice instead! Once I'm home I will pop the case and answer your question.

Thanks for the help so far....
Jim

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Re: Right. I'd try swapping the

Apple's cards were often filled NE, NW, SE, SW when banks were laid out 2x2. How are yours laid out vs. filled?

NW (labeled bank 4)empty NE (labeled bank 2) filled

SW (labeled bank 3)empty SE (labeled bank 2) filled

Not being an ET can I swap around the chips by hand or is there a special tool for removing or installing them?

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Tools? Who needs tools?

Try not to shuffle your stocking feet around on the carpet just before you start. Touch something metal and grounded first. The power supply is a good place.

There are chip pullers out there. You can also use a small (jeweler's) screwdriver and gently pry each end of a chip a little at a time. It's important to unsocket each one slowly and evenly, so you don't bend the pins. There is a key on each chip - a notch or a dot, pointing at the end that contains pin #1. Keep an eye out for that; they will all be the same, and will all be oriented the same way.

Reseating the chips will be another delicate task. You've got to wedge all the pins in essentially at once. Sometimes, if the pins bend outward more than the sockets, you have to carefully bend them in so everyone fits. It's a delicate process, and one that benefits from some experience. Here's hoping yours is a good one. Smile

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Use a hammer to seat'em

This will be a weekend project when I can take my time...I'll be back after I give it a try.....

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a couple of points

Before I mess with the chips on the board let me get a couple things straight in my head.

1)I am making the assumption that the eight chips in each bank are like a series circuit..fry one or more chips and the bank will not function?

2)The chips, if all the banks are not full, must be put into the banks in a certain order. If placed incorrectly, then the computer will not "see" the bank that is out of order?

sorry for all the questions...learning as I go here.

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Re: a couple of points

1)I am making the assumption that the eight chips in each bank are like a series circuit..fry one or more chips and the bank will not function?

True. I, on the other hand, am making the assumption that the "chips" are of the Dual Inline Pin (DIP) variety... the ones that look like little centipedes.
2)The chips, if all the banks are not full, must be put into the banks in a certain order. If placed incorrectly, then the computer will not "see" the bank that is out of order?

Very likely true. There were designs in existence where you could specify, or it could detect, where there was viable memory. But probably not in this particular case.

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Re: a couple of points

I, on the other hand, am making the assumption that the "chips" are of the Dual Inline Pin (DIP) variety... the ones that look like little centipedes.

Yep..that is what they look like....now is there a way to test these while they are installed are am I getting in over my head?

Also I guess there could there be a problem with the card itself?

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Re: a couple of points

...now is there a way to test these while they are installed

Not really, no - except for asking the computer how much it sees. Which isn't helping us much. Smile
Also I guess there could there be a problem with the card itself?

Could be... but probably not. If it's working at all, it'll probably be working for all banks. Unless it got folded in half and some of the traces are broken, or some other unnatural act has befallen it.

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A few bad chips?

I removed and swapped the banks around....at power on I checked and the control panel showed only the ram installed on the motherboard. I then swapped the original chips in bank 1 back to bank 1 and got the 1.2 mb back.

I figured that to find the bad chip(s) that I will have to take one at a time and insert it into bank 1 with seven known good chips until I have checked all 8...right?

GSE-Reactive has P21010-08 chips available, but since mine are p21010-07 can I mix these chips even though they run at different speeds? or no.

Thanks
Jim

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Re: A few bad chips?

I removed and swapped the banks around....at power on I checked and the control panel showed only the ram installed on the motherboard. I then swapped the original chips in bank 1 back to bank 1 and got the 1.2 mb back.

Now you're getting somewhere!

I figured that to find the bad chip(s) that I will have to take one at a time and insert it into bank 1 with seven known good chips until I have checked all 8...right?

That sounds like as good a way to check as is possible.

GSE-Reactive has P21010-08 chips available, but since mine are p21010-07 can I mix these chips even though they run at different speeds? or no.

I think that it will be fine. If we just assumed that 1 over the time was the clock speed (which I don't reckon it is) then you'd be talking about like 14 MHz. I also seem to remember that the earlier Macs used like 150ns parts. So 70's and 80's ought to be plenty fast. Also, I just checked for the memory card that I had for you- unfortunately no P21010's, but what looks like some 256 Mbit, 150ns parts. So yeah, I wouldn't sweat mixing and matching GSE's stuff with yours. I wish I had some chips to donate!

Glad to see you're making some headway,

mike

Thanks
Jim[/quote]

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New Chips

Going to go ahead and order new chips for all four banks from GSE-Reactive and keep my original chips that are good as spares. Thanks for the help!
Now my monitor is acting up...to use an old cliche "when it rains it pours". Oh well, it is a 21 year old system guess I will have a few problems Smile

Jim

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yeah.

Every time I power up mine I wonder if it will boot. Smile Hope the infusion of memory chips does the trick! Sorry, all, about the sloppy quoting above.

mike

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