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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Spordan on September 16, 2006, 05:07:50 PM
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Hi, I picked up an A1200 at a carboot sale today for a couple of quid (the seller had no idea if it worked or not, so I brought it on the presumption it was faulty).
I should mention this is the first amiga I have ever used (I was poor back in the early 90's :P), and although it came with a bunch of stuff, a manual was not among them :0(
When I connected the power and RF cable to the TV, I saw the 'insert disk' screen, although very fuzzy (as you might expect from an RF cable), however, I had to turn it off and move the 1200 temporarily (someone else wanted to use the larger TV downstairs).
Since then, I can get no video output from the a1200, either with an RF cable or composite (I don't have a 15hz monitor to check the video).
When I power it up, the tv screen changes to black (indicating it is getting a signal), but the disk screen never appears.
The A1200 makes what I presume to be disk-checking noises every hmmm.. 10 seconds or so, but as I have no experience with these, I am not sure what is normal :0(
Does anyone have any idea what I might have done to it, and how to fix it?
I stripped it down to the motherboard and cleaned it (If it matters it is a 1D.4 version, though that's from memory) but this has made no difference.
If anyone can offer me any advice on what to try, or if you need any more information, please let me know, as it's a shame to find one with a lot of games and stuff, and then break it 5 minutes after getting it home :'(
I thought perhaps something could have overheated/blown, since this is probably the first time it's been powered up this decade, but i'm hoping someone may know more about what to check.
Many thanks!
Spordan
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Did it have any expansion modules plugged in at the bottom ? Do any LEDs come on ? Does it have a hard drive ?(It shouldn't as you get the insert disk screen)
To be honest they are a very rugged machine, but if it has any add on bits, the power supply often fails. Let us know more !!!
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Thanks for your quick reply, in answer to your questions:
There was no expansion modules plugged in at the bottom.
The green power light comes on, and the one above it flashes green (theres a chance it might be the power LED flashing, it's hard to tell as it's quite faint).
It has a seagate hard disk (the cable was slightly loose when I stripped it, but since I reassembled it firmly, it's hard to tell whether this has made a difference with the screen being black.
Is there anything else I can check?
Thanks for your help! :0)
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Since you got the insert floppy disk screen when you started, the Miggy could not initially see the hard disk. Now you have reconnected it, the Miggy doesn't work.
I'd go for disconnecting the hard drive to see if it will boot up without it (Could be faulty hard drive OR power supply unable to feed all loads). Can you borrow another power supply from anyone ? An A500 psu is slightly higher rated and less likely to fail.
Since you don't know the history of the machine, it will be a matter of trying things one by one. :-D
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Okay, thanks for your help, I will try your suggestions and see if I can get it up and running :0)
Thanks again :)
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I agrre with what's already been said, but....
Have you re-tried it in the original set that gave you a picture?
There maybe nothing wrong, it could be that the HD wasn't working until you fixed it. Now when it boots off the HD a non-TV-displayable mode is engaged..... maybe.
Try rebooting while holding down both mouse buttons. This should give you the early start-up screen.
The disk clicks are normal, but there are utilities you can use to stop them. :)
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Hi, no, unfortunately I'm at home now, and the first tv set I tried it on was my girlfriend's fancy high definition set :P
I have tried stripping back to the motherboard and giving everything a good clean, and reconnecting floppy, trying that, reconnecting just the hard disk, and connecting them both and holding down the two mouse buttons.
The situation now is this:
I power on the 1200, the power led turns green, there is a click from the floppy drive, and the hard disk makes a typical hard disk noise (which it wasn't before, so that's a step in the right direction, I hope!) :P
the tv turns grey/black, so I know it is outputting a signal.
every 4 or 5 seconds, there is a flash of colour (purple, i think) then back to grey for 5 seconds. It keeps repeating this, so i think it might be the insert floppy disk screen, though i'm not sure.
Would it show the floppy disk screen if the hard disk was connected but blank, or damaged?
Should the A1200 output a video if I power up just the motherboard with no disks attached?
You mentioned to try holding the two mouse buttons in case it is in a different video mode - when I got the a1200 there was a VGA adapter plugged into the Video port, so presumably the seller used a monitor, I don't know anything about Amigas really, so is it possible it's in some sort of mode my TV cannot understand? I know amiga's need a 15hz monitor, so I can't use my PC one, but is there some sort of mode that would make it not display correctly on a TV?
Thanks again for the help! :)
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You mentioned to try holding the two mouse buttons in case it is in a different video mode - when I got the a1200 there was a VGA adapter plugged into the Video port, so presumably the seller used a monitor, I don't know anything about Amigas really, so is it possible it's in some sort of mode my TV cannot understand? I know amiga's need a 15hz monitor, so I can't use my PC one, but is there some sort of mode that would make it not display correctly on a TV?
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Yes, definitely. And its likely if the guy was using a vga adaptor. The Amiga can use modes that will not display at all on a TV, but by using the 2 mouse button thing at boot up, it will bypass that entering the TV-friendly pre-startup screens. From there you could try selecting boot with no startup, and then typing loadwb into the cli, if the hd is working.
Other thoughts... Leave the floppy connected for now, if the above fails you should try running with no HD. have you any floppies to try booting from?
Sometimes, the Rom chips need a gentle but firm push to re-seat them (at your own risk!). But obviously turn off the power before doing any of that, and also before connnecting or disconnecting any cables. The connections are not buffered and can blow - even the joystick ones apparently, though its not happened here.
Best of luck.
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Right, just had another go with it, but still no luck, booting with both mouse buttons pressed doesn't seem to make a difference :0(
The power LED flashes 6 times, then a long flash, and repeats.
Does anyone know what this means? is it normal, or is it an error code?
Thanks
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is it possible that it keeps rebooting over and over again every few seconds?
what would make it do this? :0\
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Hi Spordan. Try what he suggests. If you open the 1200 up, (after unhooking all cables and grounding yourself) and lift the keyboard up, down in the lower middle, you'll see a 3" square metal box, lift the little tabs, take the box cover off, and you'll see two chips, which are the ROMs. Its possible that they have become unseated, and simply require firm pressure to seat them again. The resetting is usually because the ROMs are loose, or possably bad. Good luck.
Oh, and welcome to Amiga.org. Coolest place on the web.
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Hi, thank you for your reply!
I think the a1200 is definitely resetting, i wasn't sure before as i'm not familiar with what I *should* be seeing :P
At the moment, having removed, then reseated the ROMs, I get a light grey screen for a few seconds, that then resets and this keeps looping.
Does this mean the ROMs are bad? Is there anything I can do about this? are they available to buy anywhere, or do I have to buy the blanks and use an EPROM programmer or something? :0(
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If you go to the homepage of Amiga.org, and go all the way to the bottom, you'll see a link that lists companies that can help you. In america, there's Softhut, in Europe there's Amigakit as the main retailers, but there's others listed so shop around.
Also, try this, before you turn it on, hold both mouse buttons and keep holding them as it boots up. A screen should come up to give you a choice of PAL or NTSC, or Original chipset or AGA.
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a little update: I just managed to get to a black screen that said "Software failure" in red (or something along those lines).
Does this fit in with the theory of bad roms?
I don't want to buy more if the actual motherboard is damaged or something :P
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Someone else help Spordan here please.
If you take the HD off, does it do that?
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I have only been able to get that 'software failure' screen twice, other times it just sits at a grey screen or reboots.
The same seems to be true without the hard disk connected.
It is a shame because the actual motherboard is surprisingly clean and new looking, but I can only guess there must be a bad solder somewhere, or one of the chips is damaged :0(
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Hi! Be sure you press and hold the two mousebuttons as you switch the computer on. It is possible (i guess- I'm fairly new to the Amiga myself) that the start-up sequence contains instructions that require expansions that have been removed prior the sale. Good luck!
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Hi! Be sure you press and hold the two mousebuttons as you switch the computer on. It is possible (i guess- I'm fairly new to the Amiga myself) that the start-up sequence contains instructions that require expansions that have been removed prior the sale. Good luck!
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Should the A1200 output a video if I power up just the motherboard with no disks attached?
Yes. The amiga should boot to the instert disk screen without both floppy drive and hard drive and i suggest that this is what you do. I believe the led blinking pattern is a error code, but i sadly do not know the error codes myself. I am sure there are plenty of people here who do though?
I dont know if you are good with voltage meters and such? Because it could just as easily be the PSU that is getting old and is not outputting the right voltage anymore. So checking this with a voltage meter might be a good idea.
Also if you try it without both HD and floppy, then also make sure you also disconnect power cables as well as the ide cables.
The software failure can be either due to buggy software or a hardware problem.
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Thanks for the reply guys.
Does anyone know if the error message I saw means the ROMs are okay?
If the chips were damaged, I wouldn't have been able to get that message, right? :0\
I will give the PSU a look at tomorrow morning with the 'meter, failing that, i'm not sure what to do!
If anyone knows where I can find information about the error codes, please let me know :0)
the power flashes 6 times and one long time.
If I can't repair it, i think i'll probably end up ebaying another one, as this one came with a lot of software, etc.
Cheers guys! :)
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@Spordan
I think there may be some metal making contact with the Motherboard.......and NO I dont think that Software failure screen means the ROMS are bad.
I think maybe even you connected the Hard drive incorrectly.
I would totally remove it for now...make sure the floppy connector is fully attached and make sure there is no wires making contact with the motherboard in anyway............its quite possible that after testing it on the RF TV, you did something to kill it. Who knows.
But I have had a similar problem..and it meant that something wasnt connected right or that there wasnt enough Power from the Power supply.
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Check out this link for info about the flashing.
http://main.aminet.net/hard/misc/errormessages.txt
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Hi
That link is dead (at least for me)
try this instead - http://de5.aminet.net/hard/misc/errormessages.txt
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Thanks for your replies, guys.
I have tried powering up just the motherboard with nothing connected, and I still face the same problem, I will check again today to make sure there are no visible shorts.
I have found a couple of web sites via google that describe using a PC ATX power supply to replace the Commodore PSU.
How easy is this? I have a spare 400W ATX PSU, is it simply a case of snipping the A1200 connector a few inches down and attaching the wires directly from the ATX PSU motherboard?
Does the A1200 use the same voltages a ATX PSU delivers? 12, 5, etc. Or is it different and i'll have to make up a PCB or something with resistors?
Thanks again! :0)
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Does anyone know if the error message I saw means the ROMs are okay?
Here is a site that tells you what these errors means: http://main.aminet.net/hard/misc/errormessages.txt (http://main.aminet.net/hard/misc/errormessages.txt)
I sadly cannot see 6 power flashes there though.
One blink The keyboard ROM check failed
Two blinks The keyboard RAM check failed
Three blinks The watchdog timer test failed
Four blinks A short exists between two row lines or one of the
seven special control keys
Red If there is an error in ROM
Green If there is an error in the Chip RAM
Blue If an error was found in the custom chips
Yellow If the 68000 found an error before the error
trapping software (the guru) was up and running
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I do not know about ATX, but i believe they sell amiga convertors for AT psus. But can you first try messauring the amiga psu using a multimeter? And the voltages is the same as a PC psu.
http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/body_amiga_power_supplies.html (http://www.ianstedman.co.uk/Amiga/amiga_hacks/Amiga_Power_supplies/body_amiga_power_supplies.html)
You can find some info here regarding making a normal psu into a amiga one.
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Since you already disconected the hard drive and floppy with still no change, I would say it's most likely a problem with the power suppy or perhaps the mainboard itself.
You said the power led is flasing which might also indicate the 1200 isn't geting enough power.
You should first try converting your old ATX and see if that makes a difference.
If your in the UK and still in diffs PM me.. I have a spare power supply and mainboard you can have for free :-)
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I agree with Akiko here as the error messages (as far as I can remember) are output to the Caps Lock LED - not the Power LED. Incidentally, my power LED flashes too - but that's down to a faulty LED.
Have you connected your audio up? One of my A600's PSU's went faulty which resulted in all sorts of graphical/boot problems and also a 'machine gun' cracking noise through the speakers.