A1200 video problem, please help! :P

[Spordan]

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 ), 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

[Homer]

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 !!!

[Spordan]

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)

[Homer]

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

[Spordan]

Okay, thanks for your help, I will try your suggestions and see if I can get it up and running :0)
Thanks again

[Angus]

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.  

[Spordan]

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

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!)
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!

[Angus]

**********************************************************
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?
*********************************************************

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.

[Spordan]

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

[Spordan]

is it possible that it keeps rebooting over and over again every few seconds?
what would make it do this? :0\

[Amiduffer]

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.

[Spordan]

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

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(

[Amiduffer]

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.

[Spordan]

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

[Amiduffer]

Someone else help Spordan here please.

If you take the HD off, does it do that?