Battery damaged, dead A4000D - Weird Diagrom serial output

[kbj]

Hi all,

 

I'm trying to repair a dead A4000D.  When it arrived, I had a black screen, nothing else.  I've cleaned up the corrosion and i've repaired tracks and replaced a few chips (the RTC, U711, U891) around the battery and also 2 SIMM sockets (the CHIP RAM socket and the bottom FAST RAM socket nearest the edge of the board).  I also recapped the whole board.

 

 

I also noted when it arrived that there were 2 caps burned up under the kickstart sockets on the bottom of the board (C175 and C176) which I replaced.  A lot of current must have gone through those.

 

I've powered it up using an ATX PSU with an Amiga Kit ATX->Amiga4k cable as I'm not sure about the A4000's PSU yet - that's for another day 🙂

 

Burned a couple of ROMs with DiagROM 1.3 when I received the board and got nothing on the serial output.  After the work above, I now get an alternating green/red screen (Green for a while, then red, then back to green) and DiagROM is now outputting some info - but the text is VERY slow - about 1 char every half second or so (See the video attached).  It also outputs some (what looks like) RAM test info, but I've not seen it before..

 

Anyone have any ideas?

 

Cheers,

 

KbJ

 

 

 

Edited January 22 by kbj
Video in wrong place

[+chue]

Perhaps some clues here: https://github.com/ChuckyGang/DiagROM/blob/master/DiagRom Codes.txt

 

Looks to me like chipmem errors, but I could be wrong.

[+OLD CS1]

Red boot screen indicates a ROM error, green indicates Chip RAM error.

 

EDIT: This might help your process.

https://www.amigalove.com/viewtopic.php?t=324

[kbj]

15 hours ago, chue said:

Perhaps some clues here: https://github.com/ChuckyGang/DiagROM/blob/master/DiagRom Codes.txt

 

Looks to me like chipmem errors, but I could be wrong.

Thanks @chue - I have these and I've used DiagROM a number of times to sort Amigas - just never seen the kind of output from it that is in the video.

[kbj]

8 hours ago, OLD CS1 said:

Red boot screen indicates a ROM error, green indicates Chip RAM error.

 

EDIT: This might help your process.

https://www.amigalove.com/viewtopic.php?t=324

Thanks @OLD CS1 - It's not so much the colours onscreen - it's interpreting the DiagROM output I guess I'm stuck with.  I appreciate your help though!

[Daedalus2097]

Green and red colours on the screen are normal for the boot process of DiagROM as it tests the chip RAM. The very slow output is strange, but given the text is coherent at least we know the bus between the CPU, ROMs and Paula is ok. Very slow output can be caused by a couple of things - bus errors/timeouts (no acknowledgement from addresses that would normally respond instantly) or a failure with the interrupts are my first two thoughts, so I would check both of those areas for damage.