My A1200 is DYING! Random crashes, HELP!

[anakirob]

(one of) My A1200's has recently started crashing at random intervals, and provides me with random guru's (one started with C86E, instead of 8000!).

Sometimes I get a yellow screen (I know what this means) on boot.
Sometimes I get no video and/or audio signal (but video returns when I reset?!).
And sometimes it won't start @ all, although I still get the power LED.

Can anyone please, PLEASE, HELP ME?!

[Hyperspeed]

Sometimes when I switch on my SCSI-IV doesn't initialise, it may be
dirty power supply or SCSI termination issues.

Again, I'm wondering if after 12 or so years the capacitors are
degrading. I know my audio-out sounds fuzzy at high volumes.

What might be worth trying is removing all plugs, accelerators/memory
boards, ROM chips etc. and then re-sitting them. This might help a
contact either due to loosening or oxidisation.

I have no other ideas, hope a techy is reading!

[EzdineG]

I think Hyper covered it with the 'ol "remove everything."  I've experienced similar (random) issues with trapdoor accelerators that wouldn't go away until they were reseated and had their contacts cleaned.  I've also had flaky power supplies that would cause devices not to work (ide chain.)

Hope this helps.

[anakirob]

Thanks guys. but I tried this already before I even started the thread!

I was looking through my old CU collection and it says random crashes are indicative of faulty CIA timers, can anyone tell me if this is the only possibility. And how difficult are these CIA's to replace? (I am not scared of solder, but I've never removed chips from a PCB before)

[Hyperspeed]

Hmm...  what I would do first is open the Amiga up, give it a quick
vacuuming inside then remove the shielding and check the motherboard
revision printed on the motherboard.

This might give you a foundation with regards to finding out what
quirks your particular machine might have.

I once had a Quantum Daytona Go-Drive 2.5" and that gave me terrible
crashes, but disable the CPU cache and it worked (but everything would
overheat after a while). This was a known problem and Go-Drives are
not compatible with Amiga.

Check to see if all other hardware isn't conflicting before looking at
the motherboard. Then before you do that, check to see that there are
no visible signs of electrolyte leakage and damaged capacitors.

What about your accelerator/memory board - is this looking okay?

It may be cheaper to get a new Amiga on eBay rather than pay £30+ for
a chip replacement. Try the basic damage location test first and let
us know what other stuff you have on the machine (ROMs too!).

Just another thought, you're not overloading the standard vanilla
power brick are you? No extra floppy drives, '030 or hard disk?

What about your power strip, it doesn't have a washing machine, oven
and cement mixer on it right?

:-D :-D

[Argus]

Sounds like either a power supply problem or the harddrive is dying.  If you have another p/s unit, try using it instead, especially if you've been using the stock a1200 one.  Some harddrives I've used seem to work okay for a while and then start to act up, giving checksum errors or random crashes.  Though it's a pain to start from scratch, re-installing your system on a new harddrive also replaces damaged/missing files, libraries, etc.  Sometimes, software installers can replace key system files if you don't use 'expert' mode and watch everything.

[kd7ota]

Just my input.

If you have an accelerator and it has 72pinn memory module installed....It may be the fact that the memory is going bad, or just offtimed somehow. But I did have a 16mb module going bad on me, which text would be thrown off and it would randomly crash, but later I replaced the memory for some 32mb, and worked perfectly since....  :-)

[Hyperspeed]

Yeah, the memory could be the fault if it's an expanded Amiga but
since SIMMs are solid state how often do they burn out?

I know that since swapping my EDO for FPM I don't crash half as much
but this problem sounds different.

When you think of the ways data degrades in hard disk platters,
floppies and CDRs... makes you wonder if we don't keep moving our
software onto the latest mediums then it will eventually trickle away!

:-o

[tolishot]

My friend i have this problems several times.i have all chip out from chip bases. i clean cerefuly all chip legs with pen delete(on greece i say goma from pencile) and i clean again the pcb 1200.check out the rom chips the color screens is a message from roms after clean the chips put again back carefuly and turn on it.by!!!

[anakirob]

Yup, it was a dodgy memory sim! I had 2x4mb, i took them both out and it works. Now I have to work out which one was the problem.

I have (several) a500 PSU's. So that's not a prob.

Thanks to everybody for all your help.