Quadra 950: DOS Cards « modelrail.otenko

24Jun/153

Quadra 950: DOS Cards

I remember back in high school that we had DOS Cards in the Macintoshes we used for Multimedia class. We were either programming Hypercard Stacks or switching to the DOS environment and fragging eachother in Doom II. We weren't meant to be doing the latter... but it was hard to resist.

I had always been impressed that the DOS side worked just as well as the Mac side and switching was seamless. It all makes sense now why the DOS side kept running when switching and why it all ran so well; the DOS card created a whole PC running independently of the host Macintosh.

To re-live all this, I wanted to find a DOS Card for the Quadra 950. Researching the cards lead me to believe that the majority would fit into the the PDS Slot, but I wanted to keep my PPC upgrade in there. I therefore began the hunt to find a Nubus DOS Card.

Some light reading...

First attempt at acquiring one

I happened across an Orange Micro PC Coprocessor Card (dated prior to the OrangePC 290) with a Cyrix 5x86 on eBay. Bidding started at USD50. I bid up to USD70. I was in the lead until the last second when the price nearly doubled to USD126. Sounds like I'm an eBay newbie but, on the contrary, I just wasn't expecting the price to go that high. I actually wonder what the final bidder put down as a max bid... only the bidder ever knows with eBay, the seller only ever gets to see the final auction price and any bids below that.

This kind of crappy bidding brings up a good point: I like how Yahoo Auctions Japan actually extends the auction in the last five minutes, for five minutes, if someone places a bid. That way, just like in a real auction, the final bidder with the most money actually wins; rather than the one with the lowest latency.

The conclusion? These things are in demand!... This model happened to be a Cyrix 5x86 SL50 and was a little below-spec anyway, so I was happy to sit tight for something gutsier.

Orange Micro: OrangePC 290

eBay alerts are all well-and-good when the sellers list their items correctly. Unfortunately, this item was listed as shipping to the US only. I usually don't bother begging, as you usually get a flat-out "no" in response, but I asked the seller if they'd ship to Australia. As luck would have it, they did... but it was through the global shipping program. Not to be discouraged, I took the gamble and bid anyway... I won!

It seems that this card was worth over USD$2500 back in the day. See The Original Macintosh DOS Compatibility Card (Houdini I) for a price list... way down the document. I haven't checked the rest of the doc for valid information on my scenario (I don't have a Houdini card), but I'll read it at a later date when I have Win95B+Plus! running on my Quadra.

This card is came equipped with a genuine Intel 486 DX4-100 CPU and 32mb of RAM. I scoured the internet and found the drivers on the Wayback Machine. Product information is here and Downloads and drivers for the OrangePC 290 are here. Installation seemed overly-easy. Running the application gave a very simple configuration interface. Thanks to all my partitions I could easily allocate the space on one to a virtual HDD file. It seems that you need to use real floppy disks instead of images... Use Disk Copy to create those via the "Make Floppy Disk..." menu item.

The first warning, as below, was that my Video mode was unsupported. As you can see, it was configured for internal video, but the desktop mode didn't seem to gel with the OrangePC card. I tried quite a few resolutions (not really trusting my MAC to VGA video converter) but couldn't get it to agree with any mode. I was beginning to wonder if this was actually a hardware issue with the card itself.

I then hit Cold Boot on the setup panel and ... nothing ... 10 seconds later an error: The OrangePC card is not responding to the Macintosh and the error code 32. I couldn't find anything on that error number, but googling the text gave the standard advice of (taken from Orange Micro's FAQ page):

Q: When I launch OrangePC, I get an Error message saying ``The OrangePC is not Responding."
Remove the OrangePC from the Macintosh. With a pencil eraser, clean the PCI contacts. Do the same for the Memory (DIMM or SIMM) modules. Reseat the memory modules on the OrangePC, and insert the OrangePC into the Macintosh. If possible, place the OrangePC card in the slot closest to the Macintosh processor.

I decided to go down the cleaning route and removed the RAM SIMM. Everything then started to become very clear... the teeth in the socket were loose. I don't even know if that's the right term, but either way the three left-most contacts were going to be making very dodgy connections... no good for low-level digital logic. I jumped straight on eBay and found a local 72-pin SIMM socket and ordered it... it's 90-degrees instead of the 22.5 angle, but it'll be a good test.

In the meantime, I removed the SIMM, put the card back in the Macintosh and tried again... this time OrangePC told me that the Memory configuration was incorrect. Slightly interesting... it can tell that the chip isn't there (there must be a latch driven when the chip is in, must be on other pins.) I unseated the CPU and checked for further damage, but it looked ok... I then inspected the rest of the board. There are dints and scratches all over it, but none look track-threatening. I reseated the SIMM as best as possible with its loose teeth and tried again.

Finally, prior to any actual surgery, I grabbed a hair-drier and gave it a once-over. The age-old trick of reheating dry solder joints is a good one. I've never tried it, but I could see dry joints all over the place. A hot hair-drier will actually slightly melt the joints and, as long as you don't angle the board, hopefully re-join any damaged connections. It's a crap-shoot, but it was worth a try. Unfortunately it didn't improve the situation.

Googling further, I came across Andrew's OrangePC 290 page. This guy is a legend; That is all. The site might as well be the technical manual for the card. So lucky to find it. It documents the jumper settings... I assume these would come set out of the factory, but they are there to be configured. It turns out that he has all the information I need for the CPU I have installed. I reviewed the jumpers, and found that they were all wrong. They didn't match the CPU installed at all. I reconfigured the jumpers as per Andrew's page... but the board still would not function.

Re-inserting it and starting OrangePC threw an error Type 1 at me... hadn't seen that before. Oh, the joys of playing with vintage hardware! Type 1 errors are address errors... I assume it's having issues finding the hardware. A reboot didn't help. I powered the machine down and was about to put the card in another slot when I realised I'd bent a pin on the Nubus connector. No wonder the software couldn't find the hardware.

Don't do anything with vintage hardware in a rush... Straightening the bent nubus connector pin proved relatively easy. I inserted it again, gently, and power up the machine. No love... errors... I think we'll see if the RAM socket repair will work.

One note, I attempted to set the video mode to external via jumpers 11 and 12. Andrew's site indicates that there are two configurations, but I tried all. The software actually registered that external mode was selected... it even stopped me from opening the internal view of the dos environment. That only confused me further... the Macintosh could talk to the card fine... it just seems that when it throws the final boot command that the card does not respond... maybe it is the RAM/CPU combo. I really don't know what the history of this card is... for all I know it's been out in someone's flowerpot catching rays for the last 20 years.

Further attempts to get this working resulted in very hot CPUs and other ICs on the board, random bus errors on boot of MacOS and system crashes left, right and center. Not much fun... this card is about to get written off as a dud. I tried reverting to 8.1, switching off the PPC card, switching back to the stock crystal. Nothing. It just wouldn't boot.

I had a lightbulb moment: I could re-wire the first loose tooth on the ram socket prior to receiving a whole new socket. I found some winding wire from my toolbox and installed it. Nothing... it still failed with the same errors... made me believe that the card was hopeless.

...this effort proved fruitless. No change in error messages.

In the never-ending quest to fix this thing, I also replaced the CPU with a valid substitute. I bought an AMD DX4-100 from a seller on eBay and gave it a go... no love.

The RAM socket arrived... I replaced the socket, but that didn't work either.

Could it be the RAM SIMM? I've another arriving sometime in the next week... will give it a go.
Otherwise... I'm beginning to think that this is a dead-loss. Time to sit back and wait for another one to appear on eBay.

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