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My new Quadra 900

valejacobo

Active member
Hey guys, first timer here. I just wanted to share my most recent purchase, a Quadra 900.

It came with an original Seagate ST1480N (It even has the apple stickers on it!) 8 megs of ram and all the vram slots filled (Wich makes me believe it has the 2 megs for that sweet 24 bit colour) and System 7.1 installed with a couple graphics software as it belonged to a newspaper before, the original Apple Extended Keyboard II and the mouse too, but I'll have to fix the click switch or source another one.

I plan to retrobright the plastics of the case and the keyboard/mouse as soon as I can get my hands on some UV lights.
It also came with a SuperMac Spectrum/8 Series III video card, but since it has a burned pin on the NuBus, I'll get some schematics so I can see if I can plug it safely without burning an otherwise working Quadra.


WhatsApp Image 2021-07-14 at 10.15.14 PM.jpeg
The behemoth of a tower next to my P3 Win98 PC

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The squeaky clean interior of the Quadra. I plan on maxing out that ram later on.
 

cheesestraws

Well-known member
Oh, that's rather nice. And yes: I suspect fewer 900s are left 'in the wild' than 950s. Hope you'll hang around and talk to us about how you get on with it :)
 

BadGoldEagle

Well-known member
Nice catch.
A word of warning though: Always use a switched power strip with those things. They don't like being hot plugged.
 

slomacuser

Well-known member
One off topic question that always bothered me. The Quadra 900 came with Mac OS 7.0.1 in 1991 and one year later the Quadra 950 was released. But the System 7.0.1 from 1991 recognise the diference from Quadra 950 that was released in 1992. So that support for next generation was prebuilt in in System 7.0.1? Do you think there is also support for other protoype machines in Sys 7 that were not released too?
 

valejacobo

Active member
Oh, that's rather nice. And yes: I suspect fewer 900s are left 'in the wild' than 950s. Hope you'll hang around and talk to us about how you get on with it :)
Thanks! So far so good, I've got the mouse click to work by putting a piece of paper folded inside getting to press a little bit against the switch, and right now I'm in the process to make the floppy work again by regreasing it and 3d printing the broken gear courtesy of a friend. I'll upgrade it to more ram when I get the money for it and get a 20' Apple crt or any size as long as one pops up locally (Kinda hard to get by in Argentina).

Nice catch.
A word of warning though: Always use a switched power strip with those things. They don't like being hot plugged.
I'll take that into consideration as to not shorten whatever life it has left. How difficult/recomendable is to get the power supply recapped? I've read that's not so advisable as the motherboards recaps.

One off topic question that always bothered me. The Quadra 900 came with Mac OS 7.0.1 in 1991 and one year later the Quadra 950 was released. But the System 7.0.1 from 1991 recognise the diference from Quadra 950 that was released in 1992. So that support for next generation was prebuilt in in System 7.0.1? Do you think there is also support for other protoype machines in Sys 7 that were not released too?
I think they were future proofing the OS with some code to recognize the then working prototypes. Most companies start developement with the release of a product being some time ahead in mind, and planing and adding some products that may be available later on current solutions.
 

cheesestraws

Well-known member
How difficult/recomendable is to get the power supply recapped?

Even if it's recapped, it's vulnerable to being hot-plugged, I believe: it's something in the design of the PSU (I am not an expert on PSUs, I am merely parroting better-informed people's opinions here!)
 

eraser

Well-known member
Recapping mine is what killed it. Heat is also a factor.

That sounds like a mistake during the recap job. There is no reason why new caps of the correct spec would doom a PSU.
 

jammi

Active member
One off topic question that always bothered me. The Quadra 900 came with Mac OS 7.0.1 in 1991 and one year later the Quadra 950 was released. But the System 7.0.1 from 1991 recognise the diference from Quadra 950 that was released in 1992. So that support for next generation was prebuilt in in System 7.0.1? Do you think there is also support for other protoype machines in Sys 7 that were not released too?
Macs of this era had their resources in ROM, and the System only updated them. A ROM could be based on a certain System version and therefore require anything newer than that, but it wasn't like you'd have to release a new System per model unlike in the Michael Spindler era.
 

BadGoldEagle

Well-known member
That sounds like a mistake during the recap job. There is no reason why new caps of the correct spec would doom a PSU.
Sure, that’s always a possibility. I took dozens of pics, bought some low ESR Nichicons for the whole thing with a higher temp rating, double checked my work two or three times with the pics and the multimeter, reflowed the boards with the hot air station, cleaned it with IPA extensively and even had a PSU professional (he repairs PSUs all day long) inspect it for me and he couldn’t find what caused its issues (in a reasonable amount of time anyway). Sure there’s always a possibility... :)

There could be a reason though: age. If a mosfet gets out of whack/spec, it certainly won’t appreciate the regained “vitality” a recap brings. If you restore an old car’s engine without touching up the transmission or even the suspension for that matter you will wear out the old components faster.

Back to the Quadra.... it’s a known fact now that those PSU are extremely fragile. There’s always something arcing as you plug it in and I saw more than one that had a blown fan controller.
 
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