A4000 help, Jim...I'm a doctor not a bricklayer

[Argus]

One of my A4000s ist kaputt.  Can't figure out exactly what happened but here's the symptoms.  Turn it on, get grey screen on monitor but no boot; hard drive spins up but no floppy click.  Keyboard can reset causing screen flash and one caps lock light flash an then same thing.  I've tried 'rounding up the usual suspects': i.e. cleaning it, changing simms, swapping roms, fast slot cleaning, w/ & w/o hd or floppy, power supply connector, etc.  There was some corrosion under on the upper left quadrant beneath Paula and the audio inputs apparently from leaking caps on the top side but I found no broken traces after cleaning thoroughly (maybe inside a via?).  The battery was removed long ago and there's no damage whatsoever in that area.  CIAs are cool to the touch though Paula is *slightly* warm (i.e. no more so that Lisa).

[hppacito]

If you have a monitor connected to the DB-23 RGB connector, check if is not short-circuited. That also manifests itself as gray screen witout boot.

[Plaz]

A bad CPU card will do that too. I've had my share. You mentioned 'one' of your 4000's so you must have a second 4000 you can try swapping CPU cards with. Maybe just reseting the CPU card might make a difference. But I think you tried that already since you mentioned cleaning the fast slot. They didn't make the CPU easy to get to in a 4000 though did they? Better than the 3000 I suppose, but Amiga's always were the poster child for bad case design. What kind of CPU do you have? I've managed to loose both a 040 and Cyberstorm card in my 4000's.
 
Plaz

[Jose]

Will the boot menu appear if you hold both mouse buttons ?

[Thomas]

First thing to look at always is the power LED. It should become lit after power-on and half a second later it should become brighter. If it does not get brighter, the processor card is dead or not connecet correctly. Compare it to your working Amigas.

If the LED becomes brighter, most of the hardware is working correctly. At least the processor, the Kickstart ROM and the CIA which controls the LED are ok.

The color on the screen does not say anything if the LED stays dimmed. Because if the processor does not set the LED bright, it does not even come to a point where it can change the screen color.

The same is true for the boot menu. If the kernel does not work, there is no way to enter the boot menu. The boot menu is the last thing to check. First the power LED, then the screen color, now perhaps the HDD led and at last the boot menu.


Bye,
Thomas
 

[Argus]

Okay, I checked the machine in a darkened room.  The power led comes on and maybe a fraction of a second later gets maybe twice as bright.  The harddrive light is on and I can hear the drive accessing like it's going to boot and then stops, leaving me facing a dark grey screen.  Suggestions?

I don't think it's the cpu card because it works with neither the a3640 nor with a known working Cyberstorm MkIII board.

And no, I can't access the boot menu at all.

[Argus]

@Thomas

Any ideas?  It seems to want to go but just won't.

[Plaz]

it works with neither the a3640 nor with a known working Cyberstorm MkIII

Couple more possiblities....
I'm assuming your Agnus is socketed, try  removing and resetting that if you havn't already. A shorted CIA chip will cause the same failure but since those are soldered to the mother board it makes them harder to test or replace. (Not to mention it's become harder to find a replacement chip.) I know you said they didn't seem hot, but that doesn't always tell the whole story. I've replaced dozens over the years repairing 500/2000's and a few 1200/4000's. I don't think I ever saw one go bad in a 3000, but I was probably just lucky. A couple were suspiciously hot, most were not. If you don't hang extra hardware off your serial/parallel ports and don't normally dis/re-connect drives with power on then the CIA's are probably ok, but they still have my attention. Unfortunatly you've done much testing already and are running out of easy fixes. Have you removed the motherboard from the case and checked for any thing suspicious on the bottom of the motherboard?

Plaz

[Argus]

Yes, I've had the m/b out of the case.  Still no luck.  The thing seems to be hanging where it should cycle to a light grey screen and complete the boot sequence.  The thing that is telling for me is no floppy is working on the external or internal ports (i.e. no 'click-click' during boot). Is this usually a CIA or Paula problem?

[patrik]

@Argus:

Try unplugging all floppys and see if it boots. If I recall correctly, you need to wait a loooong time for it to boot without a connected floppy, so dont give up after a half a minute.


/Patrik

[Thomas]

Does the HDD LED go out after a while ? If it continues to glow forever, you probably connected the HDD data cable in the wrong way. You shouldn't try this for a long time because it will fry your motherboard.

What happens if you disconnect the HDD ?

What happens if you disconnect both the HDD and the floppy drive ?

Bye,
Thomas

[Argus]

@Thomas, Patrik

Yes, after a while the HD light goes out.  I've left it running for up to ten minutes and no floppy activity.  Same thing w/ or w/o floppy, HD, etc.