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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: starf81 on May 31, 2005, 07:11:25 PM
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Hi! I've just got my "new" A1200 and now I'm testing it.
I've noticed a strange behaviour when I turn on it... despite my other Amigas, the A1200 needs a lot of seconds (I think at least 15 or 20) to start. It's the same when I reboot pushing CTRL + A + A keys: it needs a long time to display the purple "welcome" screen. Do your 1200s take so long time, too?
After, I've tested the A1200 with an Apollo 1240 and the purple screen comes immediately. However, when I use the Apollo, the Amiga crashes after very few minutes... could be the power supply? I'm using an A500+ power supply.
Last question: looking to the motherboard (REV 1D4), I can see a resistor in the lower part, at the right of "Alice" chip. It doesn't seem to be soldered by Commodore (it's not so perfect...) but the picture into amiga-hardware.com site has the same resistor. What is its function?
MANY THANKS!!!!
Alex
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I've noticed a strange behaviour when I turn on it... despite my other Amigas, the A1200 needs a lot of seconds (I think at least 15 or 20) to start. It's the same when I reboot pushing CTRL + A + A keys: it needs a long time to display the purple "welcome" screen. Do your 1200s take so long time, too?
The a1200 has an IDE bus, its simply waiting for your non-existing hard disk to spin up before it boots from the floppy drive. Quite normal on a 3.1rom Escom 1d4 A1200.
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What LinchpiN said :-)
Shove a hard disk in there and that boot delay will all but vanish.
The problems with the 1240 could be down to
1) Overheating - make sure your machine is well ventilated and that the fan on the apollo is working properly.
2) Insufficient / varying power - depending on what other peripherals you have, your PSU might he straining. The old A500 power bricks are tated at 60W, which should be enough but also bear in mind they are likely getting quite old and perhaps (especially due to drying capacitors etc) may not be delivering their full potential. If you have any spare AT or ATX PSU's lying around, you might convert one of those.
If you do opt for a PSU conversion, consider using 2 cables to the amiga, one to the normal power socket and a second (using a spare molex connector is a good choice) to power any internal drives. This reduces the current flow through the motherboard.
3) Ropey timing issues (not uncommon for older Apollos) -
trickier to diagnose and fix, but usually this prevents the system from starting at all, so with any luck it isn't this.
4) Software incompatibilites / hacks / improper setup - you say you are not booting from a Hard Disk? It is quite likely that whatever software you run from floppy is not fully aware of the 68040. The 68040 and 68060 require special libraries that configure their MMU, setup software emulation for missing instructions etc. Without this support code loaded, you can expect some weirdness with various applications. These libraries are typically installed when you install AmigaOS 3.x to a hard drive.
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First of all thanks for your replies!
Ok for the boot time...
Regarding the Apollo:
1) At the moment my machine is fully opened and the Apollo has a good fan...
2) I'll try to adapt an ATX power supply. However, when I tested, I haven't any other peripherals linked to the Amiga.
3) I was reading about this problem on several sites... :-(
Any tips about it? Is the modify sure?
4) No, I don't think... it crashes during the purple screen, too.
Another question :-D ... I'm reading about compatibility problems with my revision (1D4), including something with 31khz screen mode. Is it true? How I can fix?
THANKS AGAIN!
Alex
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Hi.My A1200 usually boots up in approx 5-8 seconds.But it came fitted with 200MB hard drive+workbench 3.0 pre-installed.I don't know about 500+ power supply,as mine came with standard 1200 supply.
Cheers-Colin.
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@Starf81
When in doubt with any accelerator card, first of all ensure that all connections are completely clean. The motherboard edge connector, the accelerator card socket, SIMMs and their sockets. Dust, grease etc, some of which might even be virtually invisible to the eye can result in a flaky contact.
Cleaning with a cotton swab and some proper contact cleaner (or Isopropyl alcohol) can be a good place to start.
Also check the mechanical rigidity of the cards attachment to the motherboard, a slightly loose or wobbly card is a common source of problems, usually resulting again in a poor contact. Same with memory too.
Does your 1240 have a socketed ROM chip (the one adjacent to the SIMM socket)? Early revisions, like mine did. And a total pain in the arse it was too. If so, check it is seated firmly. Mine used to get pushed by the SIMM once installed and it is now as good as dead due to mechanical strain this caused.
I am not familiar with the 1D4/31kHz screen issue, so I can't really say.
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Karlos wrote:
3) Ropey timing issues (not uncommon for older Apollos) -
trickier to diagnose and fix, but usually this prevents the system from starting at all, so with any luck it isn't this.
Well, as he says in a later post it sometimes crashes on the insert disk screen.
Ian Stedman has a very helpful page covering the fixes needed for the various A1200 revisions.
http://www.ianstedman.co.uk/Amiga/amiga_hacks/A1200_Mobo_fix/body_a1200_mobo_fix.html (http://www.ianstedman.co.uk/Amiga/amiga_hacks/A1200_Mobo_fix/body_a1200_mobo_fix.html)
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Doobrey wrote:
Well, as he says in a later post it sometimes crashes on the insert disk screen.
Aye, but an unrelable contact would show similar symptoms too. Always better to eliminate these things systematically.
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Ok... I've completed my tests.
I've cleaned all contacts with a spray (type G-22) on Amiga and Apollo side. It still crashes.
Rigidity seems ok as its attachment to the motherboard.
Neverthless, the Apollo has a socketed ROM and its pins are not so good :-(
I've noticed that a pin is broken and the previous owner soldered it with the nearest pin at its left. I hope they have the same function. Do you know if and where I can found a new ROM? Otherwise, anyone has an Apollo schematic to check it?
In addition, the original battery has been changed with one bigger that doesn't permit me to close the 1200's trapdoor. So the 1200 doesn't touch the table as it should.
During my tests I've noticed that the Amiga crashes when I move it... so, it should be a syntom of poor contact, but I can't find it!
If it is necessary, I'll remove the two parts as stated in Ian Stedman's site but if the problem is another I prefer to not modify the motherboard.
I'm very confused :-? :-? :-?
Alex
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about that resistor, I have it too on one of my A1200, its probably by C=. many of their products have similar patches :roll:
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Perfect, thanks!
I've forgotten a detail: sometimes, after its spontanous reboot, the screen is yellow.
Alex
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I've forgotten a detail: sometimes, after its spontanous reboot, the screen is yellow.
Alex
AFAIK That is caused by an unexpected processor exception before the proper exception handler has been set up. Could be that rom, it sounds very dodgy to me personally.
Did you buy the Apollo seperatly?
srg
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Ok, I think to have solved my issue. I've discovered a contact problem with a socket and now seems to work well (none crash for two hours...).
However I've modified the motherboard (rev. 1D4), too. I've removed the E123C and E125C components as stated in a lot of sites. All work correctly.
But... now I've another problem to solve! :-D
I'll ask about it in a new thread...
THANKS AGAIN FOR YOUR HELP, MY FRIENDS!!! :-)
Alex