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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Invisix on December 14, 2005, 02:02:23 AM
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What the hell...
I've had it in a closet for a few months, and tonight I hook it all up, and I get nothing on the screen, so I start to trouble shoot, I took the top case (it's a desktop A4000) off, unhooked the Ethernet card... still nothing. I reseated the flickerfixxer + scandoubler... still nothing. Unhooked the CD-ROM... still nothing...
I hear the HDD churn as it winds up, I hear a "beep", it's very faint, and i'm assuming it's the CD-ROM booting up... I have no floppy access what so ever, and the system keeps resetting, or so it seems... like when I open the CD door, it'll autoshut.
So then, it starts to show some of thr GURU(?) codes... it shows Red, then goes to Yellow, then it remains blank / black (I dunno if it's color, or just blank).
I know that the following Guru codes of:
RED = Bad ROM
YELLOW = CPU Exception Before Bootstrap Code is Loaded, or something along those lines.
Honestly, I dunno what could be wrong? It worked fine before I unhooked it, it has been sitting quietly in my bedroom closet for hmm... maybe 4 months or so... if even that, maybe less. :cry:
I dunno where the ROM chips are, or else i'd try and reseat them. Are they under the CPU card? (I think that's a CPU card).
It has no battery, so thankfully that's not an issue.
Any help is much appreciated! :-?
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Please tell us the battery hasn't corroded and leaked all over the motherboard :-o
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Nope, no battery is installed.
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Sorry, I didn't see that the first time. I would check to make sure that the CPU card hasn't worked loose next.
Jeff
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I took out the CPU card, pushed on the ROM chips "just in case". Reseated the CPU card, put everything back together, and still nothing...
RED then Yellow then Blank / Black. :boohoo:
How the hell could this happen though??? It was sitting in a closet for maybe 3 months... it was working perfectly when I took it down.
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Could be chip ram is bad or bad roms. I would remove everything and only add a 4MB SIMM in the top simm slot and see if it comes up. Give it like 30 secs or so as the IDE will be looking for a drive.
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The colors are normal POST. The faint beep however is comming from your hard drive... Sometimes this is normal, sometimes it's not. Try disconnecting it and see if it comes up to the "insert WB" screen. If not, disconnect everything and try it. Also be patient while it boots, it does take a few moments to start churning from cold start.
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The "beep" is immited from the CD-ROM. I've tried different configurations, and nothing is working.
The system is in a vicious "reset" loop, and the IDE light stays lit, and never goes out, the HDD is quiet except for it spinning. The CD-ROM light goes on, the system resets, the CD-ROM light comes on... over and over.
I dunno what's wrong, it could be the ROM's though, which if so then I can fix my A4000 for around $50 or so USD with replacement chips.
I might go the long road and just buy another A4000 all together.
I *DO* have an A1200, however no tower, and no ethernet card, etc. It does have a Blizzard 1260 / 060 CPU @ 50Mhz.
However I dunno what's wrong with it either... I bought it, and the Blizzard from SoftHut (around 2 years ago), and I think SoftHut screwed me over on the Blizzard card... some tech demos such as Lapsuus (shows only top left half of the demo... but that 1/4 fills the whole screen... I then see rainbow color streaks, and the system reboots, it does the samething for the tech demos Perfect Circle and Little Nell by The Black Lotus... any ideas on what may be wrong with the A1200 + Blizzard 1260 combo? :-?
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Bump
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Remove all the drives, HD and CD ROM. Remove all the SIMMs and take one from the bottom and install it on the to (Chip RAM) and report back.
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Nothing, except little white lines that flash across the screen at random.
When I plug in all the SIMMs I get the red screen, then yellow, then blank. The floppy is not reading discs, the HDD doesn't do anything. When I removed the CD-ROM the IDE light no longer stayed lit all the time.
Any ideas?
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As always, please, look at the power LED first. All colors on the screen do mean nothing if the power LED does not behave normal.
The power LED should go on with half its brightness after power-on and about half a second later it should switch to its full brightness. If it does not do this, the computer does not work at all. Usually caused by a loose or defective processor board.
If it becomes brighter ok, then it should blink about ten times while the screen shows the error color. Then the computer resets and all starts over again. And again and again.
If the power LED does not blink and the computer does not reset after ten flashes, the colors do not have any meaning. Because the first thing the Kickstart does is to switch the power LED bright. If it does not come past this point, the processor does not work and without the processor, there is nobody who could switch colors.
I cannot tell you anything else than the others: to remove the motherboard from the case, remove any periphals and try it alone. Just plug in the processor, the LEDs, the monitor and the power supply. Then switch it on and watch the power LED. And the screen. Easiest way to test the blink/color+reset mechanism is to remove the chip RAM. Without chip RAM the screen should become green immediately (after the power LED has become brighter). After the power LED has flashed ten times, the screen should go black for a short time and all should start again.
Bye,
Thomas
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Say what? :huh:
I don't recall the power led on my A4000 ever being dimmed a bit, then go brighter... if I remember correctly it does do this with the above mentioned on A1200 though, which seems to function correctly.
However my main concern is my Amiga 4000 not working after being disconnected for 3 months.
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and if all the above suggestions didn't help, the rails to take are 2:
1- try with a trip to Lourdes
2- a little check to the PSU as well :-)
If its the original one, it would have all the rights to be "tired".
Fire up the multimeter and check the voltage on the +5v and +12 v at least (during the boot as well)
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Ok, I took out the CPU card, and end up with just a black screen on startup, so I know the CPU card seems to be working correctly, since when it IS plugged in, I get the colors on the screen.
If this makes any difference, the Amiga 4000 is a Commodore Amiga, not Amiga Tech.
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Invisix . . . i don't know, how much time you are around here but (if i were you) i woult take in HIGH consideration, the suggestions given by Thomas ;-)
ah, obviously if i were you.
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Oh I know, i'm not doubting Thomas, I just don't recall the power LED on my Commodore Amiga 4000 ever being dim then brighter, or even blink. I know the A1200 does that by default, if I remember correctly.
All I know is I get a Red screen, which goes away after roughly 5 or so seconds, then goes to a blank screen. No floppy activity, IDE light stays lit (only when CD-ROM is connected), and the HDD won't read anything either.
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The power LED is the main health indicator of any Amiga computer. On the early models (A500, A2000) the LED was completely controlled by the processor (i.e. it stayed completely dark until the Kickstart switched it on) and on the later models (A500+, A1200, A4000) only the brightness is controlled by the Kickstart. The power LED is also directly connected to the low-pass sound filter. So if some music program switches off the sound filter, the power LED becomes dark/dimmed, either.
Given that the not correctly working power LED has something to do with the problem and assuming that the crashes are caused by random interrupts, I would guess that one of the CIAs is dead.
Unfortunately on the A4000 most chips are soldered to the motherboard. On an A500 you could easily swap the CIAs in order to test it.
Another point to look at is the power connector on the mother board. People have reported that over time some of the wires burn out, indicated by the insulation becoming black. Perhaps, if one of the wires has a loose contact now, it would cause random crashes, too.
Bye,
Thomas
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Yeah, i've done everything you all have said. Nothing seems to be helping it, the Power LED doesn't brighten at all, it just stays steady the entire time.
I checked the PSU, nothing blackened or singed.
By the way Thomas, it's not random, the system won't boot at all, all it does in turn on, the screen is instantly Red then blank, and sometimes goes from red to yellow, then blank and that's that... however if I leave it on in that state, it'll turn different colors such as purple, orange, etc... and sometimes I will see streaks of white lines at random.
Some folks have told me it's just bad Kickstart ROM chips.
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I had a similar problem with an old 4000. I took EVERYTHING out.. re-seated all the chips, crystals, etc..
Blew the dust out with some compressed air.. and voila, it's back alive. :)
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For my money, you've got a bum power supply. Thomas is right about the LED brightness thing, believe him.
You could try taking apart the power supply (if you don't value your life much) and look on the underside of the pcb for the p/s. I have repaired a couple where there were lead solder traces that had deteriorated over time ending up with a machine with symptoms like yours. I suspect the p/s most of all because you say the machine was working before you put it in the closet. You should also make sure that the power supply connector on the bottom of the m/b is not grounding to the case (this causes all kinds of whacko problems). A little extra plastic in this area is a good idea. A dead but recently moved machine can also be symptomatic of a bad cpu card contact. Those little pins on the cpu slot can drift over time so the cpu card doesn't make good contact. Just my five cents worth......
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Yes, The power light does do the dim to bright stages. I just started up my A4000d and it goes from dim to bright. I had my Amiga fail before and I needed to get another 3640 board to fix it but I never had the coloured screens it just wouldent boot and only showed a grey screen. Works great now.
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I would contact Jean at Amiga Center in France. He does a great job in repairs! He has repaired a A4000 and two A600 motherboards for me and the time it took to send them off and have them back on my doorstep was 3 weeks! From what I remember he charges around $100 to fix the A4000 and around $50 for the A600s. This is a good deal as a used A4000 MB or A600 costs $150+ (USA)
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Have you checked the psu?? As in checking that it outputs the right voltage and so on... It could be a dried out capacitor or something, which can happen with old hardware being unused for quite some time. Lets hope it is the psu and not some capacitor or corrosion in the amiga itself, as the psu can be easily replaced.
Good luck on finding the error.
Edit: does the hard drive itself spin up??
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Yes, the hard disk itself does spinup. :)