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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: VirtualTed on February 17, 2016, 05:08:58 PM
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Hey guys,
I’ve been reading the boards for about a week now and I think it’s time for me to ask for a little help.
I’ve got an Amiga 600 (PAL, 1.5 JUNE BUG REV.) which likes to intermittently go to a black screen with a red-text software GURU ERROR about 20% of the time when I cycle my power supply. The sequence looks like this…
• Power cycle
• Power light comes on
• Screen flashes
• Guru Error (8000 0004, 8000 0003, 8000 000B, etc.) The range of errors is pretty broad, but the first two come up most often.
However, when I CTRL-A-A then I never get an error. In this case, the power light comes on, screen flashes, hard drive light comes on, then I get the classic insert disk screen.
I have tried using original Kickstart 2.05 and a Kickstart 3.1 with the same results. I am also running these tests with nothing plugged into the motherboard. The MB has been completely removed, and all I have plugged in is the video (composite) out and the power supply. When testing the soft-reboot, I obviously have the keyboard plugged in. So, just to be clear, no hard drive, disk drive, expansion, etc.
I’ve checked the front and back of the board and I see no corrosion with a magnifying glass. The capacitors all look good to me. I’ve also done a variety of tests with at least 4 different memory checkers to thoroughly test the chip ram. No errors were found. None of the chips seem hot to me although a few are somewhat warm. I’ve re-seated the Kickstart chip about a half-dozen times with no noticeable difference. Honestly, the board looks brand new compared to some of the others I've seen pictured.
The rate of failure on cycling the power can vary. For a while it was closer to 50%. Every time I power cycle, I wait 3-4 seconds – I’m not flipping it on/off quickly.
Finally, the keyboard Caps-Lock does not blink more than once whether it boots normally or errors. So, it doesn't seem to be telling me anything.
I would appreciate ANY advice I can get as I have spent many late-night hours reading through the forums and trying to diagnose this. I really want to get my Amiga to 100%!
THanks.
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Hey guys,
I’ve been reading the boards for about a week now and I think it’s time for me to ask for a little help.
I’ve got an Amiga 600 (PAL, 1.5 JUNE BUG REV.) which likes to intermittently go to a black screen with a red-text software GURU ERROR about 20% of the time when I cycle my power supply. The sequence looks like this…
• Power cycle
• Power light comes on
• Screen flashes
• Guru Error (8000 0004, 8000 0003, 8000 000B, etc.) The range of errors is pretty broad, but the first two come up most often.
However, when I CTRL-A-A then I never get an error. In this case, the power light comes on, screen flashes, hard drive light comes on, then I get the classic insert disk screen.
I have tried using original Kickstart 2.05 and a Kickstart 3.1 with the same results. I am also running these tests with nothing plugged into the motherboard. The MB has been completely removed, and all I have plugged in is the video (composite) out and the power supply. When testing the soft-reboot, I obviously have the keyboard plugged in. So, just to be clear, no hard drive, disk drive, expansion, etc.
I’ve checked the front and back of the board and I see no corrosion with a magnifying glass. The capacitors all look good to me. I’ve also done a variety of tests with at least 4 different memory checkers to thoroughly test the chip ram. No errors were found. None of the chips seem hot to me although a few are somewhat warm. I’ve re-seated the Kickstart chip about a half-dozen times with no noticeable difference. Honestly, the board looks brand new compared to some of the others I've seen pictured.
The rate of failure on cycling the power can vary. For a while it was closer to 50%. Every time I power cycle, I wait 3-4 seconds – I’m not flipping it on/off quickly.
Finally, the keyboard Caps-Lock does not blink more than once whether it boots normally or errors. So, it doesn't seem to be telling me anything.
I would appreciate ANY advice I can get as I have spent many late-night hours reading through the forums and trying to diagnose this. I really want to get my Amiga to 100%!
THanks.
Has this board been recapped? if not i suspect it may need it. barring that it could be ram,psu or possibly add-ons, do you have a chip ram expansion?
I have had mine act up with a bad keyboard ribbon connection.
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Hey Mechy,
No chipram installed, not even the keyboard for my on/off testing which results in the guru error. The board has not been re-capped - visibly they look great but I understand that this doesn't rule out a problem with the capacitors. I was thinking of chasing that as a problem, but I'd be really disappointed if it came back and had the same issue. So, I'm trying to rule everything else out first.
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+1 for possible flaky PSU. You have another one to test with? I'm sure Mechy would be glad to sell you one, if not. ;)
(PS - his are great!)
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Hmm. I didn't really consider that it could be a PSU problem. It SEEMS to be working well enough. I don't have another to test with, but I might pop it open and see if there are any obvious issues.
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Hmm. I didn't really consider that it could be a PSU problem. It SEEMS to be working well enough. I don't have another to test with, but I might pop it open and see if there are any obvious issues.
It's 24 years old this year. The caps have to be your first diagnostic test. There's a very good chance it will fix your problem. Amigakit can re-cap your board if you can't find anyone else willing.
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Well, I guess I will have to roll the dice and hope that this fixes the problem. At $85 it's a pretty expensive gamble (I'd love to spend that on some other Amiga stuff).
Anyway, I appreciate the advice and I'll update this thread on what the results are of the recap.
(And if anyone else has any other suggestions, I'll be keeping an eye on this thread in the meantime.)
Thanks guys.
-VT
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Well, I spent a bit of cash on getting the board recapped. No improvement in the results I'm getting. The A600 still intermittently starts with a GURU 8000 0003, 8000 0004, or something close to it (but mostly those two).
Soft-kicking it never results in an error. Keyboard and RAM expansion are not plugged in - it's just the board.
Any other thoughts? I will be receiving an A1200 soon and I'll check it with that PSU, but something tells me that won't be the issue.
-T
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Well, I spent a bit of cash on getting the board recapped. No improvement in the results I'm getting. The A600 still intermittently starts with a GURU 8000 0003, 8000 0004, or something close to it (but mostly those two).
Soft-kicking it never results in an error. Keyboard and RAM expansion are not plugged in - it's just the board.
Any other thoughts? I will be receiving an A1200 soon and I'll check it with that PSU, but something tells me that won't be the issue.
-T
Too bad. But at least you can rule that out. When you say power cycling you are talking about turning the switch off on the actual power supply yeah? Not at the wall socket?
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Too bad. But at least you can rule that out. When you say power cycling you are talking about turning the switch off on the actual power supply yeah? Not at the wall socket?
Correct, I'm flipping the switch on the PSU, not the wall. Doesn't seem to make a difference either way though.
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- Guru Error (8000 0004, 8000 0003, 8000 000B, etc.) The range of errors is pretty
- 80000003 Illegal address access
- 80000004 Illegal instruction
- 8000000B Line F emulation error
From what I understand, you've booted this A600 with only motherboard, screen and PSU.
Given that, and still those Gurus I'd suspect Caps(you've swapped those) or custom ROMs with some misbehaving patches in.
I'm sure a bad PSU could also cause problems. But the last guru listed is a FPU related bug:
8000000B:
when a program tries to execute a FPU instruction on a processor without a FPU, or there is a problem with the 68040/060 library.
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Could it be a cracked choke or something where the power connector comes in? Just wondering as you say it works correctly from warm reset everytime.
Good luck with the PSU once it comes. Ideally that should have been the first thing to try.
Sorry the caps didn't fix your machine. I have an A600 in need too now.
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Thanks guys, very helpful and thoughtful posts and I do appreciate it.
I seem to have much better luck if I wait longer to switch the power on/off. If I wait about 5 seconds, it seems to have the fail rate I mentioned in the first post. If I wait a full 30 seconds, it seems to boot properly.
I would think that 5 seconds is enough time to clear memory and "start over", but maybe not? I haven't switched it on/off enough to make a decisive claim that this fixes the problem, but I have yet to see it fail if I wait 30 seconds to turn it back on and I think I've done it about 15-20 times now.
How long do you guys wait between power-cycling your Amigas?
-Ted
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It could be clearing a fault in the power supply as well, Maybe a cold solder joint.
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In general, I don't power cycle, I use ctrl-a-a (for up to 30 sec), or use a hardreset program.
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Thanks guys, very helpful and thoughtful posts and I do appreciate it.
I seem to have much better luck if I wait longer to switch the power on/off. If I wait about 5 seconds, it seems to have the fail rate I mentioned in the first post. If I wait a full 30 seconds, it seems to boot properly.
I would think that 5 seconds is enough time to clear memory and "start over", but maybe not? I haven't switched it on/off enough to make a decisive claim that this fixes the problem, but I have yet to see it fail if I wait 30 seconds to turn it back on and I think I've done it about 15-20 times now.
How long do you guys wait between power-cycling your Amigas?
-Ted
5 seconds ought to be fine.
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Well, I guess I'll give it a shot with the new PSU. I cracked it open once and it "looks" great in there, so I dunno. Don't think I'll replace caps until I tried the other.
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Just thought I would update everyone on this, even though it's been a while maybe it will be helpful for someone else.
This problem continued to remain even after using another power supply. Otherwise, the machine is perfectly fine. I just have to wait longer to power-cycle it. If anyone run across a solution, please keep me (and this thread) in mind, because even if I don't fix it, I would love to know what the real problem was and I'm sure someone out there may have something similar.
Thanks for all the help.
-T
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Just thought I would update everyone on this, even though it's been a while maybe it will be helpful for someone else.
This problem continued to remain even after using another power supply. Otherwise, the machine is perfectly fine. I just have to wait longer to power-cycle it. If anyone run across a solution, please keep me (and this thread) in mind, because even if I don't fix it, I would love to know what the real problem was and I'm sure someone out there may have something similar.
Thanks for all the help.
-T
I've seen GURU's like that on my A4000 system if I don't have the filesystem in the RDB. For example if I have my boot partition setup to use SmartFileSystem and SmartFileSystem is not in the RDB I will get GURU's. Once it's in the RDB it is fine, the GURU's go away.
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Gurus at power cycling are not uncommon - just make sure to give the machine enough time between flipping the switch off and then back on again. This used to happen with my dad's A2000 even back when it was "new" in 1990/91. Waited a few more seconds before power on and all was well.
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Gurus at power cycling are not uncommon - just make sure to give the machine enough time between flipping the switch off and then back on again. This used to happen with my dad's A2000 even back when it was "new" in 1990/91. Waited a few more seconds before power on and all was well.
Thanks Matt. I think I'm coming to that realization. The machine is perfect otherwise and I'm forgetting how these older devices need a little more time between flipping on/off the switch.
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I would consider 5 secs very short time between power off to power on.
It's probably enough to drain the caps in the PSU, but there are other caps in the machine as well, and some caps in circuit with the ram, could maybe need longer to drain fully.
For example, the X1000 manual specifically says to wait at least 30 seconds to power on again after a power off. This is probably a huge safety margin, but i would still consider 5 seconds to be very "hasty" as Threebeard would have said. :-)
When resetting a router, you often pull the plug for 10-20 seconds.
Amigas are delicate, old ladies. Treat them like an old, vetaran diesel car. You take your time to glow, then start, then let it run a min or two before driving, to let the engine warm up a bit.
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I remember that a lot of computer manufacturers in the 1980s recommended a full 30 seconds between power cycling. Two seconds or even five seconds would be too short for machines from this era.
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and some caps in circuit with the ram, could maybe need longer to drain fully.
The dram will also take a while to reliably lose their contents. AmigaOS keeps some data in ram that survives resets. It may not be happy if some of it has been corrupted by a couple of seconds without being refreshed.
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I have an A4000T which has an extreme manifestation of this problem.
I have to keep the power off for up to two minutes in order to prevent the Guru from returning after a bad crash. Needless to say it's quite an inconvenience.
I have tried several different CPU cards. No difference.
Power supply has been checked for both voltage and noise. No problem there. Reset has also been checked. It pulls low cleanly for at least 500ms and returns to a full 5V.
Even more weirdly, I can sometimes cause this problem by adding or removing a Zorro card, and if I do this and turn the machine back on within two minutes I get no boot and a blinking power LED. Wait for more than two minutes and the machine then powers up perfectly!
It even remembers the kind of crash too. If I had a red software failure message, that's what I get again if I power up too soon. Likewise if it's a black screen and blinking LED, or simply no boot at all, even though the power LED changes brightness.
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Is that with the original Commodore/Amiga Technologies PSU?
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I have an A4000T which has an extreme manifestation of this problem.
There is really nothing you can do. AmigaOs tests AbsExecbase and its checksum for consistency to distinguish between a cold start and a reboot. If the RAMs keep their contents well enough - and later and more "modern" RAMs do - then the system will consider your power cycle as a reboot, even though a lot of other resources are damanged - which will then later on just cause a crash. It's a very principle problem that cannot be avoided.
Aminet should contain a couple of programs that simulate a full power cycle. It's actually not that hard, you "only" need to damage execbase "hard enough" to make the system believe that you have power-cycled the machine and go through a complete re-initialization cycle.
The only question I would have is why Ctrl+Amiga+Amiga isn't good enough in your case.
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I have the same problem with an A500 rev6a too :(
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I have the same problem with an A500 rev6a too :(
I had a look at this with the A500 and A600 a few months back. The short explanation is that it's a minor problem with the power on reset circuit in both of these models. If there's a fairly quick power off-on cycle, then the circuit that is supposed to hold the system in reset state for about 470mSec while the 5V supply stablises doesn't get triggered because a capacitor used in the triggering of the reset circuit hasn't discharged, meaning the machine begins program execution before the 5V supply has stabilised because reset isn't asserted at power up, which essentially results in the software failure message because the CPU is trying to talk to other system components before they're ready.
It's only the A500/A500+ and A600 that has the problem. i.e. if it receives a power cycle that's a bit too fast, then sometimes you'll get a software failure alert on power up. The reset circuit on all the other models works a bit differently and doesn't have the problem.
I've not tested this solution, but most likely it can easily be corrected by putting a small signal diode (e.g. 1N4148) across R711 (A500/A500+) or R611 (A600) with the cathode (stripe side) towards the 5V end of the said resistor, and the anode connected to the side of the resistor that connects to pin 2 of the 555 timer IC.
What that will do is cause the 100nF capacitor (C611/C711) to discharge immediately at power down. So during the next power up cycle, the 100nF capacitor will be discharged, meaning that the 555 based timer circuit will get triggered and correctly wait 470mSec before bringing the machine out of reset state.
Hope that helps.
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I have an A4000T which has an extreme manifestation of this problem.
I have to keep the power off for up to two minutes in order to prevent the Guru from returning after a bad crash.
The problem in the A4000T is different to the one I mentioned above; mine does this too from a cold power on. From what I can tell, it's something happening with the IDE driver in ROM. If you power up the A4000T, with the standard v40.70 ROM, and something connected to the IDE interface, then you get the guru message with Error=80000025 Task=07C02228. But it eventually gets over that and boots normally. And a warm boot is OK. The problem doesn't happen if you're using SCSI only and nothing connected to the IDE interface.
I was doing some testing recently with the ROM software developer and this A4000T power up error problem is resolved in the Cloanto v45.64 (3.X) ROM. You'll need the specific A4000T version of this, which I don't see on the AmigaKit.com website. Not sure if it's officially available or not yet, send them a query.
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I've not tested this solution, but most likely it can easily be corrected by putting a small signal diode (e.g. 1N4148) across R711 (A500/A500+) or R611 (A600) with the cathode (stripe side) towards the 5V end of the said resistor, and the anode connected to the side of the resistor that connects to pin 2 of the 555 timer IC.
Thanks, let me try it :)
Also take a look at the Cyan box, possible to test or should I replace them? :hammer:
(https://thumbs2.imgbox.com/03/cc/ljAvejpu_t.jpg) (http://imgbox.com/ljAvejpu)
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I've not tested this solution, but most likely it can easily be corrected by putting a small signal diode (e.g. 1N4148) across R711 (A500/A500+) or R611 (A600) with the cathode (stripe side) towards the 5V end of the said resistor, and the anode connected to the side of the resistor that connects to pin 2 of the 555 timer IC.
Unfortunately it didn't help and I still get random errors at startup (not for the first time) e.g. #00000003.00001970
(https://thumbs2.imgbox.com/5a/0a/Dwfg0Mqs_t.jpg) (http://imgbox.com/Dwfg0Mqs)
Also take a look at the Cyan box, should I replace them?
(https://thumbs2.imgbox.com/03/cc/ljAvejpu_t.jpg) (http://imgbox.com/ljAvejpu)
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Unfortunately it didn't help and I still get random errors at startup (not for the first time) e.g. #00000003.00001970
Also take a look at the Cyan box, should I replace them?
Looks as though you've got the diode fitted correctly. At power up, just before you get the error message, is the system being held in reset state initially?
The easiest way to tell is to measure at pin 3 of the 555 timer IC (U42) at power on. It should always be high (about 3V to 5V) at power on for approx. half a second, then go low (0V). If it's doing this and you're getting the error, then there's another problem. If it's not doing this, then there's some problem with the reset circuit.
The other two resistors you mentioned are for 5V power out the mouse/joystick ports. The 5V pin has been shorted to ground at some point and the resistors have been very hot. If your mouse is still working, then they're probably still OK. Measure across them with the power off, they should be about 4.7 Ohms each. But regardless of their condition, these can't cause the power on error.
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Not sure exactly, I see the dark gray, gray, white then #xxxxxxxx.00C01570 error and sometimes only black screen.
I measured pin3 and seems it's fine.
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Not sure exactly, I see the dark gray, gray, white then #xxxxxxxx.00C01570 error and sometimes only black screen.
I measured pin3 and seems it's fine.
That's potentially a different problem then, the one I described affects things much earlier on, meaning you'll get the guru message before the colour change.
Just to clarify, does this only happen following a brief on-off-on power cycle? It could also be a problem that the reset on power on isn't holding the system in reset state for long enough.
Keep in mind that the 5V supply has to fall low enough to trigger a reset in the first place, which would be to at least 1-2V at a guess. If the power interruption is too brief, the supply brownout can be enough to cause system operation to fail, but not to trigger the reset circuit, meaning it'll need a soft reset, or a longer power cycle, to restore operation. Which is why later designs used a proper supply monitor, or made the power supply do this - which is the purpose of the PG (power good) output from power supplies in A3000, A4000, etc.
You'd need to find a better way of testing it in your A500. Easiest way is to get a dual trace oscilloscope, set the time base to 100mSec/division, connect Ch A to the 5V supply and trigger on the rising edge, connect Ch B to pin 3 of the 555 timer IC.
What you'd expect to see is that on power up (when the 5V supply becomes active), timer pin 3 goes high almost immediately, stays high for approx. 470mSec, then goes low (bringing the system out of reset state).
If it's doing that, but the time is much shorter than expected, then there's probably a problem with capacitor C712 (10µF).
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It only happens when I turn off/on power supply.
Ok, I'll replace C712 too.
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If it's doing that, but the time is much shorter than expected, then there's probably a problem with capacitor C712 (10µF).
Unfortunately, replacing C712 didn't help too :(
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Unfortunately, replacing C712 didn't help too :(
As mentioned, you'll need to make a few measurements to figure out where the problem is. The approach of "replace random component x and hope that fixes it" gets old pretty quick.
See my previous comment about how to test what the reset circuit is doing at powerup when you get the Guru message. You'll need to determine if it's working correctly or not to understand where to proceed from here.