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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: hishamk on September 04, 2012, 06:57:38 PM
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I've recently pulled out my 1000 out of storage, stripped it up and cleaned it. It works like a charm except for the drive.
The internal drive was acting temperamental, giving read/write errors on perfectly good disks (tested on my 1200), so I made sure it was real clean. Took it apart and cleaned it up with isopropyl alcohol, including the heads and everything else in the mechanism that I could access. Before re-assembling everything, I did a quick test and everything seemed fine. All disks that previously spewed errors loaded fine without any errors.
Once I put everything back together, the read/write errors popped up again. I thought that perhaps the monitor maybe a little bit too much weight (14kg max according to the A1000 manual). Would be strange though if it is, since it's a C= 1084S. I weighed it and it came at around 11kg.
I placed the monitor beside the machine rather than on top of it anyway to see if this will sort things out and it did. No more read write errors. Everything is back to normal. :biglaugh:
The question is: I'd really love to have my monitor back to where it belongs (on top of the A1000). Is there anything that can be "fixed"?
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That is interesting. Do you think it might be a magnetic field from the monitor? It would seem strange given that they both should work together. If you put the monitor close to the disk drive but not on top, does it have any problems?
-P
PS
The Amiga 1000 is a sexy looking machine!
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When you cleaned the drive - did you take the A1000 apart to get the drive out? If so, you did replace the metal shield over the drive? For giggles, try a few sheets of aluminum foil lying on top of the case and then put the monitor back on to to see if that "fixes" things. Not that you would want to keep things that way, just as a test.
Does anyone here know whether over time the old A108X monitors might emit MORE RF interference?
Good luck!
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Monitor magnetic emissions could be it, I thought about that. I'll do some proximity testing tomorrow and let you guys know. The 1084S hasn't been switched on for more than 17 years until last week when I felt like going retro with the 1000 :D So maybe something's deteriorated over time?
As far as the cleaning goes, everything went back in, including all the shields, screws, etc. It's a stock machine btw, PAL, no daughterboard.
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Interesting! Refer to http://www.amiga.org/forums/showthread.php?t=62595 (http://www.amiga.org/forums/showthread.php?t=62595) for a similar problem I had, and how I solved it. (Even if your cable isn't old, it may be being folded or bent too much. Also, where, exactly, is your HD within the case?)
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Just a thought - when you cleaned it with isopropyl, you didn't wash away any of the intended lubrication on the rails or worm screw or any other parts, did you?
If it's not magnetic, then it might be the pressure/weight of the monitor is enough to move certain parts out of alignment within the disc drive.
I would tend to think it's the magnetic field, too...
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I had a problem with the dual (crt) monitor setup on my PC. The magnetic field from the monitors interfered with each other and caused weird patterns on the screen where they were closest. I put an old side panel from a PC case in between the monitors and the problem was solved. You could try that.
What I'd try would be to take the weight off the A1000, but keep the monitor in the same position. Say by using a "bridge" to support the monitor.
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I've recently pulled out my 1000 out of storage, stripped it up and cleaned it. It works like a charm except for the drive.
The internal drive was acting temperamental, giving read/write errors on perfectly good disks (tested on my 1200), so I made sure it was real clean. Took it apart and cleaned it up with isopropyl alcohol, including the heads and everything else in the mechanism that I could access. Before re-assembling everything, I did a quick test and everything seemed fine. All disks that previously spewed errors loaded fine without any errors.
Once I put everything back together, the read/write errors popped up again. I thought that perhaps the monitor maybe a little bit too much weight (14kg max according to the A1000 manual). Would be strange though if it is, since it's a C= 1084S. I weighed it and it came at around 11kg.
I placed the monitor beside the machine rather than on top of it anyway to see if this will sort things out and it did. No more read write errors. Everything is back to normal. :biglaugh:
The question is: I'd really love to have my monitor back to where it belongs (on top of the A1000). Is there anything that can be "fixed"?
Okay, I'd like to take another stab at this one. I deleted my original response because it was more suited to issues with an internal HD. However, since your symptoms are so eerily similar to those I experienced, I'd like to conjecture that it may well be the age of your components, and the weight of the monitor on the case. Have you tried moving the monitor around a little bit, to see if any thing changes? Also, it would be very helpful to know just what, exactly, is going on inside that case once the monitor is on top.
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Some Commodore monitors (like the Amiga 1080) actually had a metal plate screwed in under the monitor to help with the interference when placed on top of the Amiga 1000. Which 1084S monitor do you have? Some of them look just like the 1080 and others do not (boxy) Take a look under the monitor to see if it has a metal plate. If not you can use some Aluminum foil folded over a few times and place it under the monitor whilst it is on top of the A1000. :P
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Some Commodore monitors (like the Amiga 1080) actually had a metal plate screwed in under the monitor to help with the interference when placed on top of the Amiga 1000. Which 1084S monitor do you have? Some of them look just like the 1080 and others do not (boxy) Take a look under the monitor to see if it has a metal plate. If not you can use some Aluminum foil folded over a few times and place it under the monitor whilst it is on top of the A1000. :P
This statement is absolutely correct up to the Aluminum foil part. While aluminum is an electrical conductor, it is NOT a magnetic one. A grounded, thin sheet of iron-based steel between the monitor and the A1000 will make the best shield; i know that metal plate on the monitors was not grounded, but a grounded shield is the best interceptor of electro-magnetic radiation. You can run the ground wire to most connector posts, the center screw of a wall plate, whatever.
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Are your components plugged into grounded, three pronged outlet? Is the outlet properly grounded? Finally are all of the original shielding plates in the computer?
Sorry to just hit you with more questions, but the answer may lay there.
I would seriously doubt a weight problem. Look toward interference.
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Aluminum foil worked for me on one of my computers... Read/write errors without. None with it...
- Edit - But from what I remember it didn't work 100%. So iron or Steele would be best.
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Actually I remember having this problem with my A1000, but it was with the external A1010 drive beside my A1080 monitor not with the A1000's internal drive. I moved the drive and the problem went away.
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Alrighty, the culprit is the 1084S's magnetics. I've tested it repeatedly by holding the monitor above the A1000 some 1-2 inches (without it touching the case), and it consistently causes read/write errors.
To shed some light, this 1084S is not the original monitor that was used with the A1000 when it was purchased around 1987, but a later model 1084 that was purchased circa 1991 and used with a 500.
According to BBOAH, it's a 1084S-D1 to be exact: http://www.amiga-hardware.com/download_photos/10842sd1_1_big.jpg
Underneath, I could see the underside of the circuit board clearly. There doesn't appear to be any shielding.
So it may be that good ol' chicken lips decided to cut costs and make even more shoddy monitors, ala the "Magneto (http://en.wikipedia.org/wiki/Magneto_(comics))" edition 1084S-D1 I've got, :afro:
I'll probably hunt down an early model 108x (if someone's got a nice clean one, preferably in the UK, I'd be much obliged :) ).
FWIW, my drive cleaning prolly added a few more years to the drive. One question though - I don't believe I've wiped off any grease that I've noticed, though would it be a good idea to spray certain areas with WD-40 or the like?
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Good detective work!:banana:
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FWIW, my drive cleaning prolly added a few more years to the drive. One question though - I don't believe I've wiped off any grease that I've noticed, though would it be a good idea to spray certain areas with WD-40 or the like?
The original grease should still be doing its job. WD-40 would be a bad idea, it's not designed to stick around long, and it's far too thin anyway.
Glad you found the culprit though. So in the end was it magnetic or RF interference causing the problem? I know you said magnetic, but how did you come to this conclusion (not that it matters, just curiosity I suppose)? :laugh1:
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May I help?
The floppy heads do use electricity to do their dirty deed, but this is "wired" into a closed loop; the magnetic read/write field is in an open loop doing their job a few microns above the magnetic media, so free to other fields. RF frequency also causes "open loop" problems with things like antenna's and sensitive audio circuitry, but in this case the monitor is the main culprit: it uses magnetic fields to direct the location of the fired electrons onto the screen. Just for educational purposes grab a strongish magnet and put it next to or on a CRT's screen and watch the fun begin: without a degaussing function it can be hell trying to undo the effect (a good reason to use an LCD)
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A tape head demagnetiser will easily fix a CRT should it go all psychedelic. I had to do this on my old monitor years ago after the degausser circuit blew up and left me with a rather colourful screen.
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A tape head demagnetiser will easily fix a CRT should it go all psychedelic. I had to do this on my old monitor years ago after the degausser circuit blew up and left me with a rather colourful screen.
It is not as easy as you make it sound, but this is why it is magnetic rather than electrical (RF) interference