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Old 18 February 2009, 18:11   #1
Iznougoud
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Instability issues, A2000

I've finally managed to get my A2000 online (as a matter of fact, I'm writing this using it) - and it's due time I confront the instability issues that's been plagueing it. The system is as follows:

A2000 (ROM 3.1, rev 6.2)
Phase 5 2040 accelerator
Picasso II+
128Mb FastMEM
AOS 3.9 (boing bags and so on)
A SCSI-HDD and so forth and so on..

The symptoms are simple; random crashes and lockups (mainly immediate reboots). And by random, I do mean random. It can run for hours, and it can crash almost as soon as I try to run a program. I can't find any pattern in this behaviour (other than WhichAmiga, which always cause a lockup).

I've excluded the Blizzard-board as a cause, which leaves me with the entire motherboard as a possible suspect (I don't believe the Picasso-board is to blame). Hence I thought I'd drop a line, to see if anyone might have any bright ideas as to where to look and what to test.

This isn't a major disaster, but it is annoying. I suspect there could be an issue with memory addressing, but haven't been able to confirm that with any available software.

Suggestions, gentlemen?
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Old 18 February 2009, 18:22   #2
TheCorfiot
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Try Different Memory SIMMS with your CPU Card,
or
remove 64MB & set card to run at 64MB, IF problem persists then swap the 64MB over with the ones previously removed & try again.

Failing that clean your edge connectors, & finally is the PSU able to cope, that is a pretty loaded A2000.

Let us Know

TC
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Old 18 February 2009, 19:53   #3
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I've tested the Blizzard-board in another A2000, using the exact same SIMMs, with no symptoms whatsoever. So I believe it's clean, as are the SIMMs. If there are memory addressing issues, they are probably traced to the motherboard in some manner. Which would leave me the PSU - ah well, not sure what to do with that one....

Last edited by Iznougoud; 18 February 2009 at 19:59.
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Old 18 February 2009, 20:13   #4
DoogUK
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Swap the innards out for an ATX one, thats what i want to do to my a2000.

There's a good guide on using ATX supplies on this page:

http://www.ianstedman.co.uk/Amiga/am..._supplies.html
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Old 18 February 2009, 21:14   #5
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check the mem with a mem checker / or fill ram drive, just puting the ram in a diffrent machine is not really testing it
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Old 18 February 2009, 21:54   #6
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I've tested the RAM with various RAM-testers (none of which entirely reliable from what I can tell). Out of these, one reported errors. And continued reporting errors even when all SIMMs had been removed. When testing the board in the other A2000, I ran that very software, and the test ran flawlessly. Hence my conclusion.
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Old 18 February 2009, 22:01   #7
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Sorry if I'm stating the obvious, but did you try re-seating all socketed chips? I had a similar issue once with an A2K, turned out to be a flaky Agnus connection. Also might want to try temporarily blowing some air at the CPU and see what happens (if it's not already cooled).
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Old 19 February 2009, 11:30   #8
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I fear I've already tried that, although not all that obvious. Still. It might be worth another try, involving actual removal and re-socketing. I would hate to break anything though, given the kind of "superglue-nature" of the components of the A2000s motherboard.

Cooling may be a problem, but not one causing this. I've tried every imaginable cooling solution (including active cooling).

Edit: which reminds me; the only piece of software that is persistant in locking up the system is WhichAmiga. Without the accelerator though, WhichAmiga works just fine (which initally made me focus on the Blizzard board). This not happening using another motherboard with the accelerator however, makes me conclude that there must be something going on that (possibly among other things) affects that slot. Or possibly just a random incompatibility with WhichAmiga, an occurance not unheard of from what I understand.

Last edited by Iznougoud; 19 February 2009 at 11:57.
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Old 19 February 2009, 11:59   #9
DC33
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This might sound strange, but as you are in Sweden (way cooler than Australia), do the crashes happen when the room temperature of the day is on the warm side of things? If you find this might be the case, then it could be that you have a "dry" solder (as an example) on the 2000's motherboard.

However, you do say it is at random, so it may not be the case.

Usually, as is the case, electronics have a funny reaction to heat...

Hope this helps
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Old 19 February 2009, 19:35   #10
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Had a look at the Agnus chip, but couldn't have removed it without inflicting permanent damage. Had a look at the jumper settings while I was at it, and I must say - would it have killed someone at Commodore to release info on what the default settings are?

"J300 This jumper determines the time base used for the 50/60Hz CIA timer chip. In the normal posistion, the 50/60 TICK clock, based on AC line frequency, is used as a time base. In the alternate position, the verticle sync pulse from the video section is used. The system will not operate properly without one of these clocks."

Crystal clear, don't you agree? Anyone want to take bets on which one is the alternate position, and vice versa?
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Old 20 February 2009, 22:07   #11
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IMHO - don't bother removing the chips completely, unless there are visible signs of corrosion. Just give them a gentle press until they stop making the "crunch" noises.

WhichAmiga is just weird with certain hardware. It's intermittent on my A2K as well. (It will even crash my A1200 under certain circumstances.) Don't worry about that, A2K isn't fully supported anyhow IIRC.

PSU is a possibility, I'd suggest measuring if possible. Any other hardware bits in there? I had a DKB Multistart, where the little fly on the Gary pin would ever-so-slightly wiggle over and bridge another pin, causing random lockups. Make sure the oscillator on your Blizz is making good contact in the socket.

After checking the PSU, try booting into a _clean_ WB3.1 install, let the blanker run for a while and see what happens. If it locks, try pulling the Picasso and try again. Then try removing something else, etc.

I know it's frustrating, but you'll get it sorted! I've been going through the same issues putting together my A2K. Finally (knock on wood) it's getting stable, but there's been lots of "fun" little problems getting there, lol.
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Old 21 February 2009, 06:27   #12
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Bah! Spoke too soon. Mine (A2K/TekMagic/etc/etc) is doing the exact same thing - random lock-ups and reboots. It's definitely worse when cold, then the amount of time between freezes gradually increases as it warms up.

I think the next step for me is replacing all the capacitors on the motherboard, the symptoms are similar to my A1200/A600 boards before they were done. (On a similar note, I think this is why the 31kHz video on my A3K is goofy until it runs for a few minutes.) I'll report back in a week or so and let you know if the new caps cure it. :/
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Old 21 February 2009, 10:07   #13
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I suppose it's little comfort to us knowing this is a common problem. If nothing else, judging from what you've just told me. Then again, the hardware is getting older, so I guess one shouldn't be surprised.

As for the capacitators, they all seem healthy on my board. At least visually (which often is a good indication of their condition). So I won't bother with them. I'll see if I dare converting an ATX-PSU, otherwise I'll probably just wait for another A2000-motherboard coming my way.

Regardless. Good luck with your A2000, Damion. Hopefully we'll both contribute to the continued well being of the model
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Old 24 February 2009, 15:33   #14
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Thought I'd make an update:

In general, things are improving. Although the system still behaves strangely in some aspects it seems to be more consequent.

One of the more curious aspects is that Xopa always reported errors concerning integer and floating-calculations. I even contacted the author of that program, who informed me that this wasn't uncommon when using one of the faster 68k-processors. I haven't given it much thought since, and all of a sudden - Xopa reports flawless operation of the CPU. From what I can tell, a result of me changing position of the J300-jumper. Which might, and I stress might, mean a PSU-problem. Provided it was at its default setting when I changed it.

ArtEffect3.0, I might add, constantly cause a lockup and reboot when I try starting it. But at least that happens every time. Which is comforting in its own weird way...
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Old 27 February 2009, 12:23   #15
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Glad to hear you've made some progress! It's nice when you can enjoy using them without worrying about the next crash.

Replacing the PSU caps seems to have cured my reboot/freeze problem. (90 minutes so far without a freeze... that's definitely a record.) I'm guessing there must have been some excessive ripple on the +5v line. The voltages checked out OK before (if a tad on the higher end of the allowable range), but new caps, dialed the +5v down a hair and it's finally rockin'. Still going to replace a few on the motherboard, as I have no clue what the flaky PSU (a 300W "BigFoot") subjected them to. :/
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Old 27 February 2009, 18:10   #16
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Actually, I have a spare A2000-PSU somewhere. So I guess I can afford experimenting some. If I find a usable ATX-PSU, I'll can use that connector and - either fry, or cure my Amiga
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