A4000 sudden read errors and df0:?? ( and strange floppy behaviour)

[mike-]

Hi, Well now i've done it, or something.

I've run into a snag, lets say i boot from the Workbench or Install 3.1 floppy, it boots, i eg. insert the install 3.1 go to install, and at any random point read errors occur. I take the disk, insert the wb31 disk, or any other disk and it says df0:??. I can power down, power almost straight up again, and it wont boot from the floppy either, just the floppy struggling like the floppy was bad. Only when i leave it off, or let it cool down it works again for a short while. I've noticed Paula and Alice are running quite hot, especially Paula, even with no or little activity it gets quite hot.

I've dissected the amiga, i have it in bits and parts in front of me now, i've cleaned the immediate area around Paula. Changed cpu cards, fdd, cable, and i dont know what else, i think it happened quite suddenly, i had installed 3.9 got some weird errors with the cdrom, tried reinstalling, and got some other weird errors, like the 3.1 icon borders hanging around, so i decided it had to be the rom-update so i retreat back to the cozy and familiar 3.1 only to discover this...

Now, a significant part of the story is that the cppc is seriously faulty ( but seemed stable in certain striations ) and i was fiddling with this earlier when having unexpected issues.

Any clues at all?

EDIT: im now also seeing GFX corruption, im beginning to suspect faulty caps

[rkauer]

 Looks like faulty caps for me too. Or a bad PSU or motherboard PSU connector.

 The list of capacitors is the very same as any A1200/600.

[Plaz]

EDIT: im now also seeing GFX corruption, im beginning to suspect faulty caps

This could also be a sign of a failing Agnus depending on what it looks like. I've seen those go bad that way before. Also when an Amiga floppy decides to go bad, it can go quickly. Do you have a cleaning floppy or another Amiga you can try it in?


Also try formating new disk and copying some files back and forth. It could be you've just scratched up some of the old disks. That can happen in a blink. It worked fine this time... the next time you try it, it's gone for good.


Plaz

[mike-]

Tried two fdd's same result. The corruption happens basically along side the errors, parts of the screen gets corrupted. The mail system in france must start to wonder the heck what i do with these computer parts i keep sending down.

I've had some strange gfx corruption in 31khz aga mode for a while, basically lines getting distorted, things becomming unreadable and so on, however i've just used the mediator and voodoo5 which seemed to work fine, tho later thats gotten corrupted aswell. Might the root cause to all my problems..

[mike-]

@rkauer

Its in a mirage 4000 pro so i dont think its the psu

[rkauer]

 Don't thrust in an ATX PSU.

 If you have an oscilloscope or a signal analyser, measure the ripple on the +5V line, must be less than 50mV RMS.

[mike-]

I know there was a guy or guys who had a complete cap. replacement service going, but now i cant find the story, anyone know how i can get in touch?

rkauer
No scope no ;\