There's a saying which can be abbreviated as 'KISS', or 'keep it simple stupid'. The argument is obviously, if you keep something simple, it's more likely to be successful. So, from that, you might be getting the feeling that I've found something stupidly simple to do with the Triple X. And you would be correct.
One of the main things that has bugged me about this machine is why, when using a perfectly good ATX power supply, there was only 4 volts on the 5 volt rail. Was it a short on the board? Could it be a faulty chip leaking current to ground? In the efforts to try and find out I:
- de-soldered every capacitor and checked every one (some were out of spec to be fair)
- de-soldered every chip and tested each one (also added sockets to every chip)
- spent hours tracing the tracks to see if there was a broken or damaged track somewhere causing problems
- bought a spare DMA controller chip (MC68450)
- attempted to buy an MMU (MC68451) but found they are the proverbial rocking horse sh*t
- dismantled, cleaned and re-assembled the power supply plug that plugs into the motherboard
- swapped the 68010 into an Amiga A500 to check it worked (it did)
- checked every DRAM chip on the motherboard and Limpet expansion board (twice)
- read up on the DMA controller and MMU to see if I could work out if any signals were missing or going astray
Well, guess what dear reader. It was none of those things. Tonight, while contemplating what to do next, I had the Torch switched on and, on this boot, I had fairly dark lines running down the screen.
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| Ah, the usual garbage on screen. |
I happened to move the cable from the ATX power supply and I saw that the lines almost all disappeared. I fiddled a bit more with the cable and the unit went off. Could this be the source of the problem?
My cable setup was a bit convoluted. I had the ATX power supply with standard Molex plugs. This plugged into a Molex socket with fly leads which where then connected to the actual Torch power cable via 'choc-blocks'. The point at which I could affect the display was at the purchased Molex socket... So I removed it from the setup and cut off one of the Molex plugs from the ATX PSU so that the red, yellow and black wires went straight into the connector blocks.
I did not expect this to make any difference, but when I switched on the PSU I saw immediately that the red LED on the Limpet board flashed. I had never seen it do that before. And then, after about five seconds or so, the pale blue screen changed to dark blue with the text 'Caretaker 1.3' shown at the top.
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| The best thing I've seen on a screen for a long time... |
Oh. My. Gosh.
And then, after another few seconds, two more lines appeared with the message 'SCSI Controller 0 not present' and 'Please insert the key disk'.
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| No SCSI controller - not surprised as it's not plugged in! |
Oh. MY. GOSH.
Trembling, I reached for the Torch ring that contained the hard disk and floppy drive. After some more power connection shenanigans I turned the machine back on....
....and the hard disk died. Or more accurately, it didn't really spin up. This was a bit of a disappointing surprise. I re-checked all the cables and tried again. This time, the drive managed to spin up, but then, as I brushed the power cable, it span down. Did I have ANOTHER dodgy connection? Yes, yes I did. This time is was the plug on the hard disk itself. It was tarnished with a slight hint of green, presumably from the battery vomit. I took the drastic step of desoldering the plug so I could clean it properly - which I did - and then I re-installed it.
Back on the bench, I had just the hard disk connected up to the disk controller board and main Torch unit - balanced a little bit precariously - and switched on.
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| Is this a GUI I see before me? |
OH. MY. GOSH.
The hard disk works. Or at least it works enough to read the static RAM and realise it's missing the required security information.
And then, to cap it all, I decided to plug the keyboard and mouse in to see if the mouse would move the pointer. And it most certainly does. All I need to do now is get the floppy drive plugged back in and try the security disk. It'll almost certainly lose any settings it picks up when it gets switched off (and then demand the security disk again) until I can rig something up with batteries to stop that happening.
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| A slightly precarious setup. |
And then I hit a snag. In my haste to get the floppy drive connected to the Torch I connected the data cable to J2 on the disk controller, instead of J7. I didn't notice this at first but when I booted up again, with a 'sacrificial' disk in the drive, just to check everything would work, nothing happened. It was only after about five or six boot attempts I realised my mistake.
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| Cable plugged into J7 which is correct this time... |
The sequence of events went like this. After another failed boot I wondered if there was an issue with the floppy drive itself. So out came the Greaseweazle and, after a few minutes of fiddling I found that reading disks was not working properly. Specifically, the bottom head was reporting much lower flux levels than the top. Looking at the track analyser in the floppy disk emulator confirmed my worst fears. The bottom head is not working at all.
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| Top looks fine (left), bottom not so much (right) |
So then I went back to the controller board and checked the connections and, would you believe it, I'd plugged the floppy drive into one of the control connectors for the MFM hard disks. Now this should not have really had any negative affect on anything, but it looks like, thanks to my impatience, it may have damaged the floppy drive. Of course, it may be coincidence and the head just went bad, but as a great man once said, "There's no such thing as a coincidence.".
Fortunately, I have another floppy drive available from the venerable Cifer. It's a much simpler drive but it should (I hope) do the job.
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| To the rescue! Sort of! |
*Narrators voice* "But it did not do the job."
Sadly, no matter how I configured the drive (I had fiddled with the drive selection jumpers before and the manuals are particularly bad at saying what the drive number should be!) I just got the same results. Grey screen, icon demanding the key disk.
So I am now in the position where it looks like the motherboard is working OK, the Limpet board RAM is working OK, the keyboard and mouse are working OK and the hard disk is working OK (hence the grey screen demanding the key disk), but I cannot make the floppy drive read the key disk. The objectively terrible manuals don't really say whether the floppy drive should access disks automatically or if there should be some 'secret handshake' on the keyboard to kick things off. It's almost implied it's automatic, but not explicit.
I'm off to do some thinking...
PS I decided to try and get the BlueSCSI working as I have disk images from the Torch. After a bit of fettling I got this:
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| Well, that's not right. |
Fortunately, a quick rename of the image file on the SD card and things went a little more smoothly. It just appears to work. So now the Torch can tell me to insert the key disk even faster...
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