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Amiga as test pattern generator.

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Katie Bush
(@katie-bush)
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All done and working, thanks for the Tip Marion.

Glad to be of service...  ?

Marion

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Posted : 19/03/2015 10:21 pm
Anonymous
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I have had old hard disks that will not spin. The fix I found is to remove the unit from the case and power it up. They usually spin without a data cable connected. Hold it up in one hand and tap on the corners with your knuckle so that the case rotates sharply in alternate directions around the platter axle. This often frees them up.

Another fix that can be tried for an HD that won't spin up:

Remove the HD from the computer. Holding the HD horizontally in your hand, swivel your wrist back and forth so that the HD rotates back and forth. It's a bit hard to explain easily, but I hope you get the idea.

The idea is to jerk the platter a little, hopefully overcoming any stiction that may have happened in the bearings. In the case that worked for me, the HD had not been used for a while. But after it was freed up, it worked OK.

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Topic starter Posted : 21/03/2015 1:33 am
Anonymous
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Like trying to waggle an old-fashioned watch or alarm clock to get it going again after it has been overwound?

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Topic starter Posted : 21/03/2015 2:05 am
Terry
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A description more appropriate to this forum would surely be rotating an Avo 8 back and forth to demonstrate the movement damping when the meter is correctly left in the AC-DC position ...

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Posted : 21/03/2015 12:45 pm
Anonymous
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I seem to recall that, in my days of servicing and calibrating Avometers, we would leave the AC switch set to 10 A and the DC switch set to 50 uA, as this provided better damping than Avo's recommended settings.

John

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Topic starter Posted : 21/03/2015 12:58 pm
hamid_1
(@hamid_1)
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Great thread!

I was quite heavily into Amiga computers at one time. Back in 1996 I surfed the Web on an Amiga 1200 with 60Mb hard drive and external 28800 fax modem. It was very slow, though. I soon got a PC and gradually abandoned the Amiga.

I still have the Amiga 1200 with 60Mb HDD, an Amiga 500 with A570 CD-ROM drive and another A1200 with 127MB hard drive + 4MB extra RAM which I bought in a car boot sale many years ago. I used to have an original Amiga 1000 desktop computer (110V NTSC imported model), but gave it away 15 years ago. Big mistake - it's worth hundreds of pounds now.

Anyway, this thread encouraged me to dig out the Amiga 1200 with 127Mb HDD+6MB RAM and see if it still worked. To my surprise, it booted up perfectly, loading Workbench OS from hard drive in a few seconds. It's funny that we now have PC's hundreds of times faster than the Amiga, but they take longer to load. It also surprised me that the Amiga's 23-year-old Seagate ST9145AG hard drive worked straightaway, without any hitting or shaking necessary, and it hadn't been used for about 15 years.

Nonetheless, I've now swapped the original hard drive for a 1Gb CompactFlash card fitted in a 2.5" IDE to CF adaptor. The Amiga now runs silently and with no moving parts it should be more reliable, ready for the 21st century. I confess that I cheated and prepared the CompactFlash card in a PC using an Amiga emulator, then installed it into the real Amiga. That was partly because I can't put my hands on the original Amiga Workbench installation floppy disks at the moment. I doubt they'd work reliably now anyway. Floppy disks deteriorate with age. This is a problem which will make it harder to keep vintage computers going in the future.

Now that my Amiga is back up and running, I'd like the files for the test card generator project. I think a TV signal generator is an appropriate use for a vintage computer that was, back in the day, sometimes used to to generate on-screen graphics for broadcast TV programmes. Anyone remember the ITV Chart Show from the late 1980s? The captions were generated by an Amiga.

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Posted : 21/03/2015 10:42 pm
Katie Bush
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Like trying to waggle an old fashioned watch or alarm clock to get it going again after it has been overwound?

Al

Very much so I'd say, but beware of being overly aggressive.. Modern HDDs (almost anything later than MFM and RLL types) don't 'PARK' in the sense of the older types.. The heads are essentially free to fling back and forth as you rotate/reciprocate the HDD in your hand.

Marion

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Posted : 21/03/2015 10:46 pm
Anonymous
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Now that my Amiga is back up and running, I'd like the files for the test card generator project. I think a TV signal generator is an appropriate use for a vintage computer that was, back in the day, sometimes used to to generate on-screen graphics for broadcast TV programmes. Anyone remember the ITV Chart Show from the late 1980s? The captions were generated by an Amiga.

If you send me a private message with your email address, I can send them to you. Just put them on a bootable partition, the Amiga will boot straight into the patterns.
Bear in mind the Amiga will need Kickstart 3.1 ROMS installed, with 3.0 the patterns will not display correctly as they have a higher screen resolution than kickstart 3.0 properly supports.

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Topic starter Posted : 25/03/2015 2:35 pm
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