A4000 will not boot. Help please.

[daveh35]

Hi everyone.
I have an A4000D which I have just taken out of storage after about 2 years. When I packed it away it was behaving erratically.Sometimes taking a few attempts to boot. Now it will not boot at all. Just a grey screen. There was no visible corrosion and no obvious leaking caps but I replaced them all anyway. The battery was removed before storing it away. It hasn't made any difference. Just in case I messed something up I have checked trace continuity around the replaced caps and voltages all of which are spot on.
If I remove all RAM then it boots to a green screen. I take this as a good sign although the green screen flickers off then on again once every three seconds approx.
I get the same behaviour with the original 68030 card and also an A3640 card.
Can you suggest what may be wrong or anything else I can check

 

[cpiace64]

screen green is ok, install only chipram, and power on

 

[daveh35]

With chipram installed I only get a grey screen even after several minutes waiting.

 

[cugar124]

a question have you changed the Jumpers when you changed over the Cards as the 68030 is setup different from the 68040.

 

[daveh35]

Yes I changed the jumpers when swapping backwards and forwards between the 68030 and 68040. Exactly the same results with both cards.

 

[tbtorro]

You should get a latest DiagROM (v1.2) set and see what happens.

As for new caps ('but I replaced them all anyway'), are you sure you had enough SMD rework experience to do it correctly? Bad caps usually don't cause booting issues on the 4000 but if pads were lifted or traces damaged during recap it could lead to various issues. Also if there was any corrosion in the RTC (battery) area then that's a better place look for continuity problems. Not everybody can spot corrosion without experience and right inspection, base often leaks under the TTLs or SIMM sockets in that area and corrode traces that you can't always spot without knowing where to look.

 

[daveh35]

Thanks tbtorro.
There was no corrosion or leakage from the battery when I removed it. It was just removed as a precaution before putting the machine away.
I have got the Diagroms and I am getting no output except for the grey screen. There is nothing coming out on the serial port.
I can confirm that the two roms are installed in the correct sockets and I am definitely using a null modem (xover) cable. I double checked the wiring with a multimeter to be certain.
I have used putty configured as 9600 8N1 and also done a simple cat /dev/ttyS0 in a terminal but got nothing.
Any further suggestions would be gratefully received. I can check things with a multimeter and I also have a very cheap simple oscilloscope.
Thanks.

 

[cpiace64]

check cia connection

 

[tbtorro]

Thanks tbtorro.
There was no corrosion or leakage from the battery when I removed it. It was just removed as a precaution before putting the machine away.
I have got the Diagroms and I am getting no output except for the grey screen. There is nothing coming out on the serial port.
I can confirm that the two roms are installed in the correct sockets and I am definitely using a null modem (xover) cable. I double checked the wiring with a multimeter to be certain.
I have used putty configured as 9600 8N1 and also done a simple cat /dev/ttyS0 in a terminal but got nothing.
Any further suggestions would be gratefully received. I can check things with a multimeter and I also have a very cheap simple oscilloscope.
Thanks.

It would be very difficult to give you a step by step guide, if you have no diagrom output then something serious is going on, probably easiest would be to send your board for a proper diagnosis to someone who knows what they doing. But for starters I would check clock signals, delay lines, supply voltages and _RST lines first. But it could be bad Paula, dead CIAB, GARY, GALs, the list goes on.

And again not every battery area is corrosion free just because it looks like it. If you post a good closeup picture (high resolution and in focus) of the battery area I can tell you if it's really corrosion free.

 

[vibros]

Hello,

i suggest you a close inspection of the motherboard (with a lens if you have one).
A grey screen may tell that the problem is on the cpu: something stops (or halts) it to go forward (maybe an unterrupt!).
A damaged CIA give generally a black screen and not a grey screen.

Regards
Stefano