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32-bit acorn hardware • Re: help decoding POST from A3000

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If i work backwards and say the the last block is the last block I get 00120402 which makes no sense as i get supervisor and * but its telling me Ram control failure and MemC cam mapping which all sound like address decoding fails.
Yeah you can still get that and still get to a prompt
This is my 0v rail trace so i have something going on with decoupling. I tried every tantalum and electrolytic against my peak LCR and they all look right apart from the tantalums which are all silly
Are you sure the scope's not AC coupled?
I am using a seperate bench power supply with current limit at 700ma. it says it uses abot 540ma.
700mA is a bit tight. Go for more like an amp - there's quite a high inrush AND you have the floppy connected.
lastly my video out put is faint and reversed i get black characters on a white background. I looked the R G B out put on the scope and its all 1v as i expected, i messed around with Hsynch Vsynch etc and it made no difference starts bright then fades to barley visible.
That's pretty strange! Never seen that happen. Could be borked palette writes to VIDC but I doubt it - extra weird is how you have white boxes around the text which is then on a light grey - something very very odd going on!

Statistics: Posted by IanJeffray — Fri Oct 10, 2025 8:29 pm



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