Strange A1200 behaviour... caused by overheating?

[StevenJGore]

Hi,

My AT A1200 (see signature for specs) keeps freezing, particularly when using my SCSI CD-ROM drive and/or a program or game that is CPU-intensive.

An immediate reboot or reset either results in a frozen blank screen or (more often) a flashing red screen together with dimming/brightening of the power LED. I have to switch off the A1200 for at least a minute before it will boot properly again. Once my A1200 has frozen (even after waiting a minute before rebooting) it is much more likely to freeze again afterwards than before. After being off for a substantial amount of time, my A1200 is 'back to normal' temporarily.

My immediate thought was overheating of the 030/50Mhz CPU, but since my A1200 also freezes after a while when using a Squirrel SCSI CD-ROM (which I don't think is particularly CPU-intensive, correct me if I'm wrong) perhaps there might be some other cause?

Any suggestions?
Hopefully the red screen will be a clue to somebody.

Thanks,
Steve.

[destro]

Hello there. My first Amiga was an A-1200.

If you are to up, try opening the A-1200

case and runing it that way. If it still

fails after the same amount of time then

overheating may not be the main problem.

Also try searching for Newer Drivers for all

of your Add Ons.

[KennyR]

If the A1200 isn't expanded then it won't overheat, even if you live in a desert. Basically you need a Blizzard PPC to overheat an A1200.

[PMC]

Have you tried unplugging the SCSI and powering up?

My guess is that insufficient power may be the issue here, although you Goliath PSU should be up to the job.

[StevenJGore]

KennyR wrote:
If the A1200 isn't expanded then it won't overheat, even if you live in a desert. Basically you need a Blizzard PPC to overheat an A1200.

But if the 030 CPU was getting too hot, wouldn't it cause the A1200 to freeze or even reset?

[StevenJGore]

PMC wrote:
Have you tried unplugging the SCSI and powering up?

Not sure if I have or not. I'll try it tonight!

[KennyR]

But if the 030 CPU was getting too hot, wouldn't it cause the A1200 to freeze or even reset?

The 030 isn't really known for overheating. It runs cooler than the 040, and I have an 040 with no cooler or fan on my BPPC and it's run for years. With even a small cooler on the 030 it shouldn't have heating problems.

Of course, using an expanded A1200 on a carpet can overheat it, but I think users are too quick to point the finger at overheating. Software is by far the best way to crash an A1200...

[Mad-Matt]

Another thing to check is the Memory module on the 030 card. A dirty simm or unalligned simm can cause all sorts of weird effects especially when lots of things are going on in the system.

what 030 card is it ? there maybe some timming jumpers to try if your using a slow simm.

[StevenJGore]

It's a Blizzard Mark IV 68030/50Mhz with 32MB RAM.
I'm not sure how fast the SIMM is, and I can't remember what I've got the jumper set to.
 I'll check tonight!

[patrik]

Check the text on the circuits mounted on the SIMM. If there is a -7 or -70 on the they are rated for 70ns, if there is a -6 or -60 on them they are rated for 60ns. Similar for other speeds.

When I had my a Blizzard Mark IV 68030/50Mhz I used to get somewhere around 9 mips in sysinfo with the memory-speed-jumper set to 70ns and around 10 mips in sysinfo with the memory-speed-jumper set to 60ns. You could always check that way .

You can also check the setting of the maprom-jumper by checking how big the fastram memory-block is - if it is 31.5MB then you got maprom enabled - if it is 32MB then you got maprom disabled. This can also be checked in sysinfo.


/Patrik

[amigamad]

These are the startup colors for an a1200 that idicate faults.

RED        Bad ROM

YELLOW     CPU Exception Before Bootstrap Code is Loaded

GREEN      Bad Chip RAM  or Agnus (check seating of Agnus)

BLACK      No CPU

WHITE      Expansion passed

GREY       CPU Passed

Constant white is failure of CPU.

[JurassicCamper]

Hi Steve.

Red is usually indicitive of a bad rom.

Chances are your rom is not broken but something is going on to make your Amiga think its roms are misbeahving.

Could be your Ram speed.

Remove the MAP ROM jumper so ROM is not in fast.

See if this removes the problem.

Are you using blizkick or extramodules or a 3.1 rom image.  Do you have 3.1 roms or 3.0 ?

As your amiga is dual boot does the problem occur both under 3.1 & 3.9 ?

When I first overclocked my 060 to 66mhz it crashed frequently due to ram at to slow a speed.

My 4000 was misbeaving turned out one of my 4meg simms was at fault, even though it registered ok.

Saying that my Bizzard 060/66 Amiga1200T recently began to crash loads especially when using ibrowse / samba or as you say internsive programs.

Turned out to be the motherboard. Most 1200s are 10 years old now and capacitors / transistors can degrade affecting crucial timings.

I changed the mobo and its been rock stable since.

[mikeymike]

These are the startup colors for an a1200 that idicate faults.

They could just write it on the screen, couldn't they, it would make things so much easier :-)

... /me waits for "what about bad graphics hardware, what should it do then?" :-)

[jeffimix]

Your 1200, has it the original power supply. I've heard that the original power supply is not so very good when you add things on.

[JaXanim]

Hi Steve,

An 030/50 can most definitely cause a hangup through overheating.

I had a Microbotics card with this CPU and when I fitted into my standard A1200 desktop, it stalled all the time when running CPU intensive stuff like Imagine (3D rendering - you can't get more intensive than that).

I tried a heatsink/fan and tht workrd OK (if you can stand the racket!) Eventually, I just jacked up the keyboard using rubber door stops as legs and removed the trapdoor to let air into the slot area. That worked a treet!

Cheers,

JaXanim
http://waveguide.v21hosting.co.uk