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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: SilvrDrgn on October 21, 2002, 02:36:41 PM
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Over the weekend, my A4000T (Power Tower MK-II) started acting strangely. It was running fine, then programs started locking up and when I typed in a CLI window, the characters were showing up all goofed up or not at all. Now it refuses to boot. What does a flashing yellow screen mean???
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For me that meant my 4000D died and I put all the cards back in my 3000UXD which is still working.
There is a site somewhere that tells what all the colors mean. Maybe its was AU?
Here are some of them:
RED : If an error was found in ROMS.
GREEN : Error found in the CHIP RAM.
BLUE : Error was found in the custom chips.
YELLOW: If 68000 found an error before the error trapping software
(GURU) was running.
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Could just mean that either an accelerator or the ram on board the accelerator has become loose. As you don't appear to have changed anything I doubt that its the ram (as this tends to be quite secure) but if you've got an accelerator and knocked the box that could do it.
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Actually, if any of the ram tends to get knocked loose in an a4000, it'll tend to show a yellow screen.
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My guess is power supply issues. Do you have a spare to test it with?
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METAL wrote:
My guess is power supply issues. Do you have a spare to test it with?
With a yellowscreen? I doubt it somewhat. First I'd try turning the power off, and reseating absolutely everything that can be reseated.
(that is a somewhat.... err... hypnotic avatar you have there... :-o :-D )
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Definately don't rule out the power supply being faulty.
If there's excess ripple on the 5V supply (due to lack of DC
filtering), it may cause erratic operation.
So use an oscilloscope to check +5V and +12V supplies are +/- 5% and
ripple is less than 1%.
Also try a different CPU card, anything like an EC030 card or A3640 is
fine to test with. Make sure the two clock jumpers are set correctly
depending on what CPU board you're using.
If it is a memory problem, and you've removed the fast mem SIMMs, and
system still faults, the RAM control logic (Ramsey/Bridgette?) might
be faulty?
The system should still boot fine on only chip memory, and no fast mem
installed.
After that, it's anyone's guess.
Also check all surface mounted electrolytic capacitors for signs of
leakage or corrosion (soldered legs are black instead of silver), and
black residue on PCB. I've had a few of these lately which can cause
open circuit PCB tracks. The 22µF ones tend to be the worst for
leaking.
Anthony.
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Sounds like I'm going to have a lot of fun looking for problems this weekend. Thanks for all the suggestions! I'll update when I find a solution.
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Well, my A4000T is back up and running again. Over the weekend, I had some time to tinker with it. I had to replace my CS MK-III 060/50 accelerator card. Good thing I had a spare! The old one appears to be having some sort of heat problem. It works fine for up to about 30 minutes, then starts going haywire. Swapped the RAM off of the old card onto my spare, and everything works fine again.
Now I just need to find a place to get the broken one fixed???
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Anyone have a suggestion as to where I can get my broken CS MK-III 060/50 card fixed???
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SilvrDrgn wrote:
Over the weekend, my A4000T (Power Tower MK-II) started acting strangely. It was running fine, then programs started locking up and when I typed in a CLI window, the characters were showing up all goofed up or not at all. Now it refuses to boot. What does a flashing yellow screen mean???
First question, if the power supply was the problem you wouldnt get a screen now would you? .NO of course not.
The card could be loose or any numberrof cards you have in the slots could be bent(bending). This casues a short circuit. .Simply take all cards out hook up via the old monitor. and mak sure the normal cpu card is in good and firm . Then put he rest in one by one .
the GRaphics card last. Taken care not to bend the cards or maek them to close for comfort
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dunno if you've allready tried it, but it sounds like chip creep to me.
Check all socketed chips...
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Perhaps a leaking battery? :-o