A4000 boot question

[koshman]

Hey all,

I have problem with an A4000 - it doesn't start just shows gray screen and stays there.

Please, note this is a very bare bones setup at the moment - just the motherboard, A3630, 4MB module in the Chip RAM socket and... that's it.
3.0 ROMs, Super Buster 9, recapped, battery replaced with coin cell, no leakage, metal SIMM sockets.

No daughterboard, no mouse, no keyboard, no HDD, no FDD, no case (in my parent's house at the moment so no LEDs to check).

Is any of what I'm currently missing needed for bootup?

Thanks for any tips.

Edit: I forgot to mention I am using A520 for video output to TV though this probably doesn't matter.

[koshman]

Yeah I just want to test it basically - I bought the pieces about half a year ago to use once we move to a bigger place but wife is away for the weekend so i thought I can have a bit of fun with it now.

I think I have the daughterboard (zorro riser) stashed somewhere I'll see if I can find it and try with it tomorrow.

The A520 is tested with an A600 I have here. I can also see the TV detect some input and turn greyish color so I'm quite sure that's fine.

I remember reading somewhere that A4000 actually needs a keyboard or mouse connected to work, don't remember which or if both. Can anybody confirm that?

Once again thanks for any tips I appreciate the effort.

[koshman]

Thanks for help.

The jumpers were indeed set incorrectly to EXT - so I set them to INT for use with A3630, but no change.
Even with no Chip RAM installed I just get grey screen - does it mean the issue is with the CPU card?

By the way the mainboard is recapped and repaired - if there ever was any corrosion it has since been fixed. This is my first time testing it but the previous owner sent me pictures of it running, it was through Amibay and I have no reason to doubt him.

[koshman]

Thanks for the tips but no luck.

I tried reseating the ROMs, checked for the 50Mhz oscillator and it is there.

At this point I have to assume it's the CPU card - I get the same symptoms when I just turn it on with the CPU card removed - grey screen. No signs of life from the CPU card at all.

That's all I can do for now as I don't have a spare to test.

Thank you!

[koshman]

Yeah, those numbers agree with my ROMs. Only difference I can see is the bottom number on them is different - one says 9302 the other 9252. Could this be a problem?

[koshman]

Hi,

I was able to obtain another CPU card in the meantime - an A3640. The A4000 boots fine with it to KS screen - so that's good.

Now I would like to know for sure whether the A3630 is shot. So a question - is the 50Mhz crystal (8 dil square) on the A4000 mobo needed for function even if CPU card is using external clock - in other words does it set the Amiga internal clock?

As I'm wondering it might be just the crystal that the A3630 uses that is faulty (INT), but if the Amiga also needs it otherwise and works fine with the A3640 it is likely not that.

Thank you!

[koshman]

Great, thanks. I will try to find another crystal this should be easy enough to rule out if nothing else.