The Need for Speed – Restoring a Quadra 840AV

The Need for Speed - Restoring a Quadra 840AV

The fastest 68K Mac ever made!

A 68040 processor running at an unprecedented 40 MHz, a 66.7 MHz AT&T DSP 3210 Digital Signal Processor and a maximum memory capacity of 128 MB of interleaved RAM – for 1993, the specs were enough to make any computer junky’s heart leap for joy. The Quadra 840AV turned out to be the top of the line for Apple’s 68K Macs, the fastest 68K Mac they would ever make. It was faster by quite a bit than the nominally higher end Quadra 950, and bested its running mate, the Quadra 660AV by 15 MHz. Introduced in July 1993, it was on the market for just a little under a year, being discontinued on July 18th of 1994.

Quadra 840AVs are VERY rare these days, I suspect because so few of them were made. I diligently hunted these notoriously difficult to acquire beasts on eBay for over a year before finally bagging one. In my case, it arrived with no hard drive and no operating system. There was no start up chime when the computer was powered on and absolutely no signs of life whatsoever from it, despite the seller’s assurance that it was fully operational. Over the period of a few weeks I coaxed it back to life, changing the aged (and expired) main board battery, checking the board carefully for the dreaded blown caps (Amazing! There were none!) and maxing out the RAM to 128M. I finally got a startup chime to my great relief – I had been about to declare the machine DOA and ask the seller for a full refund. In the end, we settled for a 50% discount over the sales price and both went away happy I think.

I pulled the hard drive out of my Quadra 660AV and inserted it into the Quadra 840AV as a test. The subsequent power on chimed and turned into a full and proper boot. The machine had life in it after all, and was up and running. Some quick testing turned my elation into something a bit more muted however. The CD drive ate CDs, refusing to mount them on the desktop or give them back! The floppy drive would not ingest floppies automatically as it should, and would not give them back if they were pushed in manually. It WOULD mount them on the desktop though, and so I noted with relief that the floppy controller and cabling were obviously alright.

That was it for the first boot and the first stage of this project. What followed was some lengthy shopping on eBay for replacement parts – a 4 GB hard drive, a new CD drive and a new floppy drive, not to mention the requisite AAUI-RJ45 internet adapter and a copy of Mac OS 8.1, the last version of Mac OS to run on the 68K. Weeks later, I had assembled all the needed parts and then summer vacations intervened. It has been a month or more since then, but we are finally back, and the photo at the top of this post shows the machine, its monitor and the collection of parts that collectively will become a fully operational Quadra 840AV over the next few weeks.

The sharp eyed among you will notice the GUF220 USB 2.0 / Firewire box sitting in the heap of parts. This is not intended for the Quadra 840AV, which did not support such advanced technology. Instead, it is intended to add Firewire to my PowerMac 7500, whose PCI bus has enabled me to undertake expansions like this with it. It already sports a USB card, and now I plan to add Firewire as well. Coupled with its NewerTech 400 MHz G3 accelerator, it is quite a powerful PowerMac 7500 indeed.

Anyway, back to the Quadra 840AV. The plan of attack will be to use the original Quadra 660AV hard drive once more, to get the 840AV booting. I will then replace the CD drive with the new one and then install the new hard drive. With all that in place, I will boot the machine from its newly functional CD drive using the Mac OS 8.1 CD, and install Mac OS 8.1 onto the hard drive. This will be followed by replacement of the floppy, and with that, the hardware aspect of this restoration should be complete. I have a large collection of Mac OS software, both from days gone by, when I used Quadras and PowerMacs day to day at work, and from careful trolling of some of the excellent AbandonWare archives that exist out on the web. With all of that in hand, a full software load will round out the project, producing a working and very useable Quadra 840AV.

I’ll post regarding progress as this project comes along. Wish me luck!

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