Amiga.org
Amiga computer related discussion => General chat about Amiga topics => Topic started by: Banstyx5 on January 18, 2017, 04:20:56 PM
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Travel back in time to the early 1990s, I wanted an Amiga 1200 more than anything buy couldn't afford it, so I settled on an Amiga 600 . Decades later my 600 is long gone but I decided to jump back in, and finally achieve my dream of owning an A1200. I Found a new 1200 case and keyboard, got a gotek floppy emulator, and IDE to CF adapter and a Power Supply. Last piece I needed was a 1200 board , and I found one. Got all my parts and pieces installed my OS and assembled it all. I was so excited until I turned it on and got nothing more than a ugly dark green screen. :( So close and yet so far away! My Amiga dream appears dead.
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## Red - An error in the Kickstart rom as detected.
## Green - An error in the Chip Ram was detected.
## Blue - An error in the custom chip set was detected.
## Yellow - The CPU encountered an error before the system's error-trapping code (the code the calls up the Guru) was in place.
## Black - No CPU detected.
## Grey - CPU Passed the test.
## White - CPU failure.
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It's not dead, it's just resting. :)
Has the board been recapped? Leaky capacitors are a big problem on Amiga boards these days, so that could be responsible. Acill on this forum can do the job for you.
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it has not been recapped., and nothing appears to be leaking
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What happens when you test the bare board?
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Last piece I needed was a 1200 board , and I found one.
There a lot of questions from there. Do you know if the board worked to begin with? Are the ROMs in correctly? Because they're socketed, it's often something that gets abused. e.g. odd/even ROM swapped, aligned at the top of the 42 way socket instead of the bottom, or put in backwards (which usually causes permanent ROM damage).
If nothing at all is connected to the board except monitor and power input, it should power up to the insert disk screen after about 30 seconds.
## Red - An error in the Kickstart rom as detected.
## Green - An error in the Chip Ram was detected.
## Blue - An error in the custom chip set was detected.
## Yellow - The CPU encountered an error before the system's error-trapping code (the code the calls up the Guru) was in place.
## Black - No CPU detected.
## Grey - CPU Passed the test.
## White - CPU failure.
Oh, that old list is doing the rounds again. I've lost count of the times people have asked to have their CPU replaced because there's a black screen. Red and Yellow are mostly correct but to explain more:
Red = The ROMs are working to the point where the CPU is running the ROM checksum test (one of the first things to happen at power on), but the ROM checksum failed.
Green = The exception vector setup or the chip memory test failed, basically means that the write + read-back test failed, which can mean bad memory, or something unrelated that's causing the memory not to be accessed correctly.
Blue = I don't think OS3.x does this, might have existed in OS1.x.
Black = Anything can be stopping the boot process (e.g. ROMs inserted incorrectly, some hardware fault), or the boot process failed early on. Despite popular belief, it's rarely a problem with the CPU itself.
Grey = The early boot stuff completed (memory tests, hardware setup).
White = Usually the result of a hardware timer failure, so can be a CIA fault, missing timing signal (VSYNC, HSYNC, TIC).
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Ok so this is a dark green screen really dark
Roms appear to be in correctly
With nothing connected to it, just power and video it is dark green.
I have no history on the board, but I have never seen the insert disk screen.
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if the board looks fine, I would give a good poke on all chips (they tend to lift up under heat, especially the kickstart ROMs) and switch the mobo on again.
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it has not been recapped., and nothing appears to be leaking
Even if they're not obviously leaking, I think they can dry out as well, which also causes symptoms.
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Speaking of A1200's.. I have one without a floppy or CF card. I think it works. Its gutted in a case. I guess one day I'll put it together.
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I will recheck the board when I get home and take a picture of it along wiht the screen output.
Thanks to everyone who responded. I have been a little down about the whole thing, because as you all know getting all the parts together has been very time consuming and expensive. I'd like to have something to show for mt time and money, and although I uses Amiga Forever and Emulate 3.1 and 4.1 on my PC its not the same as having a real working Amiga.
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From decades of experience.... 12+ year old electrolytic caps are all bad caps. Get them replaced. The ones in your power supply also if it's one that can be opened. If your power supply is also antique, it could be the issue. If you can, post a video of the power up. Screen flashes can sometimes be helpful in diagnosing the problem on miggies.
Plaz
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I will recheck the board when I get home and take a picture of it along wiht the screen output.
Thanks to everyone who responded. I have been a little down about the whole thing, because as you all know getting all the parts together has been very time consuming and expensive. I'd like to have something to show for mt time and money, and although I uses Amiga Forever and Emulate 3.1 and 4.1 on my PC its not the same as having a real working Amiga.
Where did the a1200 board come from? Luckily we have a guy in usa (ACILL) that does great work cheap for getting your board working. If you dont have a bright green screen (like obviously green) then you cant use the diagnostic people are posting here it would be really really green.