Crashing A1200

[maffoo]

Hi,

I've just got hold of a second-hand A1200, complete with hard disk, 030 accelerator (a Turbo 1230 Mk II, which I think is 50MHz) and 22MB RAM. It arrived on Wednesday and seemed to work fine, although I didn't do much with it. I basically just checked it was working, but I didn't have any way to get software onto it (my CF->PCMCIA adapter hadn't arrived.)

Yesterday my order (including the CF adapter) from Amigakit arrived. I replaced the 3.0 ROMs with 3.1 so I could install OS 3.5 and everything seems to boot OK, then the Amiga will suddenly reset itself for no apparent reason. I don't even have to be doing anything, it's happened while I'm playing games but today I've noticed that it will reset if left alone for a while.

I've noticed that the 030 gets very warm, I've taken the trapdoor cover off and raised the  front of the computer slightly to try to improve cooling a bit but it's still not stable. Earlier on it reset itself twice in a short space of time, making it look more like a CPU overheating problem.

Is it likely to be the CPU getting too warm? Or is there anything else it could be?

Thanks

Matt

[amigakit]

Check the RAM on the accelerator by completely filling the RAM disk with data and then purging it (delete all the data)- if it crashes -could be faulty memory.

Could be the connection between the accelerator and expansion connector on the motherboard- try removing the accelerator and testing the Amiga with some software - does it crash then?   Also caerfully clean the expansion connector.

Also check the accelerator for any corrosion (leaking batteries etc).  Check any SIMMs are securely in their slots.

Check the motherboard is lying straight on the plastic base of the A1200 - there are grooves for it to rest in.  A slightly bent motherboard can cause problems.

[mrbill317]

Amigakit , its amazing how much you help us on these boards.

What a great company.

BTW I love my Compact Flash Adapter.

[Brian]

What you describe there could just as well be power failure... what PSU do you use for the system?

[maffoo]

Brian wrote:
What you describe there could just as well be power failure... what PSU do you use for the system?

It's just the bog-standard A1200 PSU (which I suppose is a nit long in the tooth - maybe it's on it's way out?)

I've just taken out the accelerator and booted the computer to see if it still crashes, and sadly it did (after only 4 minutes :-( )

[Homer]

Yup, sounds like the death of your PSU. That happened to me when I connected an accelerator and a hard drive. Can you test it with an a500 PSU (slightly more powerful) or borrow one to try ?
You can prove if its overheating by sitting it on an unfeasibly large household electric fan with the trapdoor off and see what happens then !
Oh, and have a :pint: , it always helps  :crazy:

[motorollin]

Seems unlikely to be a power issue if it does it with just the A1200 and hard drive with no accelerator connected. Try disconnecting everything non-essential (including the hard drive) then boot to a Workbench floppy, and see if that hangs. If it does, then it may be that you have a problem with the Amiga itself. Perhaps Amigakit's suggestion of checking the positioning of the motherboard is the key? Also make sure none of the metal shielding is shorting any parts of the board.

--
moto

[Homer]

Motorollin, I disagree since when mine went, it damaged the PSU such that it would drop the power rails intermittantly. I stuck an oscilloscope on it at the time to try to work out why it kept crashing. Even with everything disconnected it still did the same.
Best bet and simplest too, is to try a different psu.
Anyway, have a :pint:  :-)

[maffoo]

Thanks motorollin, I'm trying it now (just the monitor and power connected, nothing else. (I was hoping the hard drive wouldn't be a problem as I've swapped the one it came with for a CF card, which AFAIK needs less power.)

I had a quick check of the motherboard while I was taking the accelerator out and I couldn't see any problems there.

I was also wondering, if it works fine from the workbench floppy could it indicate a problem with SetPatch (maybe it doesn't like my A1200's motherboard revision or something, and makes it unstable?) If that's the case, I can always reinstall 3.0 and Ebay the 3.5 CD...

[amigakit]

Always check the A1200 for stability problems with a Workbench floppy disk rather than booting from HD.

Perform the RAM disk test (complete fill/purge) when booted from Workbench disk to check Chip RAM.

Ensure the Kickstart chips are inserted properly into their sockets and no pins are bent.

BTW: If you want us to check the motherboard, that isn't a problem.

Hope you get to the bottom of this.

[motorollin]

Homer wrote:
Motorollin, I disagree since when mine went, it damaged the PSU such that it would drop the power rails intermittantly.

Oh sorry, I thought you meant that the PSU was underpowered, which is why I was skeptical when it was occurring with just a HDD connected. I see your point about the flaking out completely.

--
moto

[Brian]

The bog standard A1200 PSU gives 23-25W where's the A500 gives 50W. The standard PSU for the A1200 isn't ment to take any upgrades except for HDD and PCMCIA memory. Usually sticking a turbo to it fries it eventually, add an external floppy or two surtanly takes it down sooner or later. I actually fried an A500 PSU with a A1200+3,5" HDD+2 external FDD and a B1230 so that too can be underpowered (had the exact same issues with random reboots every 5sec-10min... esp when the PSU gets warm it starts to fail more frequently than when it's cold).

As you have removed the hardware that made the computer start failing and it still does fail I say the PSU have had it. Suggestion to you, try an A500 PSU and if that works then get hold of an old PC AT PSU and use the powercord from the defective original PSU to create a super PSU.

(Just a heads up here, a 200+W PSU is super but now power loss in the powercable to the computer might get to be a problem if you upgrade wildly and you might have to supply the motherboard with a second powercables form the PSU.)

[Homer]

Yup, I think that was the most normal death for an A1200 psu. Intermittant power rails ! I tried slaving in a pc psu and it worked perfectly :-)
Still does ten years later ! Its sat next to me as I write  :-D
Anyway, thats why I suggest trying another Amiga psu since its just so easy to do ! Good luck :pint:

[maffoo]

Thanks for the advice. I've tried filling and purging the RAM, it seems to work when it's just Chip RAM but when I had the 16MB SIMM in it caused a crash. However with the CF card attached the machine crashed even when it was booted from floppy, so maybe the SIMM's power requirements just pushed the PSU over the edge. I've also double-checked that the ROMs are seated properly, that doesn't seem to be a problem.

I'm going to try to get hold of an A500 PSU (there are some on Ebay, I've e-mailed the seller to confirm if they're 50W or 25W.) I was considering upgrading to a D-Box tower eventually, so once I've confirmed that the PSU is the problem I might get it towerised so it will have 350W to work with  :-D

PS. Amigakit, I noticed that you have Amiga PSUs on your site, are they 50W? If so I might be placing another order with you!

[Homer]

Might be worth mentioning where you live to see if you can borrow one for fault finding :-) Much cheaper than buying one !