Amiga 1200 crashing

I have started my process of trying to transfer files accross from my A1200 to my PC, but my A1200 keeps crashing.

It has been a cupboard for a looong time, until I fished out a couple of weeks back (we are about to move to a new flat). It is in a little poor condition- I lent it to a sister of mine(never lend loved hardware to siblings), who hadnt looked after it (I had to SCRUB the case). It has some rust (I removed what i can) on the mobo sheilding and the FDD case, and (after checking under the shielding) on the RF modulator (I use the composite output - so not a huge prob).

The KB is a bit flaky, and the left shift and Amiga key dont work - no soft reboots. I have tried reseating the KB connector - but cant get much joy. same probs with the + and - keys on the keypad.

It boots, and will load wb (as my other postings show), and I have now got amiga explorer running on it. I managed to play walker on it last week (what an AWESOME game that was), and even get audio out of OctaMED. However - it does seem to hang after a while(about 30 mins to an hour), on a white screen. This is especially after floppy drive activity. Sometimes, following this (after hard reboot) it then does the same after only 10 minutes, other times - it will fail to start at all - but make pathetic whirring and clicking sounds from what I think is the direction of the floppy drive.

I have given the floppy (since i first heard the noise) ,a good cleaning, and checked to see if there are any visible shorts or PCB track breaks - but nothing there. I moved the HDD away form its usual recess, and checked for overheating - which does not seem to be the issue.

I have tried two different power supplies (I have two genuine commodore Amiga supplies for some reason) - and both have exhibited the same behaviour. It is a geniune commodore one, and not one of the later ones - it has a Wb3.0 ROM, nothing in the trapdor slot and a 2.5in prairieteck 20Mb Hdd.

Anyway - If anybody has any suggestions on how to diagnose and repair this, i would be much obliged - I am about to try and copy *all* of my data to my PC.

Read more here abd decided just to clarify a few things:
The amiga has clearly died - it is not just video - I know this because audio stops, and if using Amiga explorer - the serial stream stops. It is not the HD - as i tried without it and still get the behaviour.
I am not afraid to use a multimeter or an oscilloscope - i have both here, I just have no idea what to look for on the A1200.

Danny

[Miggy2TheMax]

Not too sure how to fix your problem, but if your just trying to get your data across, you should be able to buy a 44pin laptop IDE to 40pin IDE, so that you can plug your miggy hd straight into your PC and use UAE/linux to mount acess it and copy your stuff across. There are docs on what a white screen means in terms of amiga hw errors, cant really remember now. To be honest bc everything is surface mount on the miggy 1200 you'd be hard pressed to be replacing things. I guess it would do no harm opening up the 1200 and taking a look if something is physically burnt out. If you have a space floppy drive try swapping that. I hope that helps a little, post updates as to how you go.

*DISCLAIMER* don't blame me if you get electricuted, blow you amiga up
as you try to do the following steps below. do at own risk!!!!

Another trick I heard to help diagnose hw problems that arise as you use the miggy. First switch in on, now as you approach your 1/2 hour when the problems
arise, just touch the top of each processor if one is beaming hot, that is you
singe your hand on it if you leave it there long than a couple of seconds, than its likely that one thats had it.

Good luck