Closed Amiga 4000 MB and CPU fault diagnosis

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Aysel

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Hi all... new to the forum but not the Amiga... I'm still running my Batpack A500 :)

I'm here looking for assistance, mid way through installing Octamed on my Rev B A4000 the screen, floppy and HD froze, I reset and was greeted by the grey screen of death. Sequence is power on, PSU fires up fine, hd spins for a few seconds with hd light on, hd light goes out then nothing other than power light and grey screen.

I have tried: Reseating 3.0 roms, battery has discoloured PCB a little but no corrosion visible, board os very clean and fresh, cleaned contacts between CPU and Mb and checked seated, tried caps lock check and only cycles six times then stops suggesting CPU is not responding. Left running for hours, booted with only CPU/PSU connected, CPU board looks pristine, no visible leaking from caps.

Mb is a rev 2... CPU board has no model number I can see but says 6820/030 rev 1 and has an MC68EC030FE25B CPU and MC68882RC50A FPU.

Ideally looking for someone uk based to diagnose / repair :)

Any assistance greatly appreciated

Thank you
 
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Hello, try to dusconnect all from your a4000 (hdd, zorro boards if there are some, scandoublers and all fast ram) disconnect power from hdd and cd too, leave only floppy drive connected, cpu board and chip ram, try to power on and look if the kickstart image show, if not, disconnect the floppy too and try again.. (without floppy you have to wait some more seconds for kickstart screen to show up)
 
Hi Juri, thanks for the advice.... I have tried everything along those lines... currently running the board with just CPU, PSU and keyboard. Left it running for an hour no change. Tried it with chip ram removed which should present the green screen but its still grey.
 
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Looks like there's light at the end of the tunnel... a very kind offer to test the board and CPU from a local member with some spares then its off to Hikey Monday to see if he can work some magic.

Thanks all for you efforts, greatly appreciated.
 
received back from Hikey this morning.... sent off, new caps,new SIMMs, fault fixed, kickstart upgraded, battery replaced with cr type, email updates throughout and back in my hands ten days later looking superb and working perfectly.... cannot recommend highly enough, Thanks again for all your assistance.
 
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