Stock A4000 040, full ram.

[Vlabguy1]

No boot up.  Screen flickers(no colors etc) briefly when power button is pushed, HD spools up but does not seem like it is getting asked to boot the OS.  Battery has been removed, before I got the machine,  no signs of MB damage from a leaky battery etc.  I see no activity from the floppy.  I insert a floppy, the usual click sound occurs but no data access activity.  Hold the two mouse buttons on power up and nothing.  Would a bad floppy drive boff the whole system from booting up?  Could it be a chip is not seated properly or in need of re-seating?

Any help, suggestions would be nice..

Thanks
Rich

[Vlabguy1]

Update:

Ug took the floppy drive out and installed in to a known working A4000 and voila the machine would not boot... I had no idea.  I also found a another issue, will post pics
soon.

[lassie]

Update:

Ug took the floppy drive out and installed in to a known working A4000 and voila the machine would not boot... I had no idea.  I also found a another issue, will post pics
soon.

It is strange that a floppy drive, could do so the hole amiga would not boot up. can you boot it without the floppy drive?

[lassie]

Update:

Ug took the floppy drive out and installed in to a known working A4000 and voila the machine would not boot... I had no idea.  I also found a another issue, will post pics
soon.

Will it still not boot when you take the floppy drive out?

[Vlabguy1]

Will it still not boot when you take the floppy drive out?

I tried taking the floppy drive out and still would not boot.  Makes sense because floppy is shot so even though it is plugged in cabled up .. no boot.  Could not even get to the early startup menu.  All know is my living room is now scattered with Amiga's.  I have not taken the processor card that was in non booting A4000 out to test that in another machine, but the problem seem to follow the bad floppy drive..

[Ami_GFX]

Black screen? If you get a black screen, press the caps lock key around 6 times. If the LED goes out after being pressed 6 or so times and doesn't turn back on, the CPU card isn't working or isn't seated right or not connecting properly. You will get the same black screen with the CPU card removed.

If there is no video output at all after the initial flicker, the power supply could be faulty.

[spirantho]

The Caps Lock light not changing after several presses doesn't necessarily mean any one thing. I had the same problem when I needed to reflow Alice's solder.
Compare the Amiga's boot flicker with that of an A1200. The monitor should lose sync momentarily, but it will be for about a tenth of a second. If the monitor just immediately resyncs without losing sync it may be the same problem as I had.
In my case because the joint was dodgy on Alice, it would occasionally boot up. Also leaving it on for a bit longer and then Ctrl-A-A would reboot it.

Do you have an oscilloscope? Check for activity on the SIMM sockets to make sure RAM is being accessed. If it's not, then the machine is probably waiting for one of the custom chips to respond correctly.

The machine should boot fine with just the PSU and the monitor connected, by the way. The keyboard is also useful but not necessary. You don't need the floppy connected.

Also, what is the voltage of the +5V line? It should be over 4.9V on an unloaded motherboard, though it may sink as low as 4.7V when everything is connected.

If you have an SMT rework station, I'd recommended a quick flux and reflow just to be sure. That's what fixed my A4000 (after years of trying to diagnose).

[orange]

I'd try reseating CPU card.

[nscaleworld]

What do you expect, it's an Amiga 4000. :rolleyes:
 
My advice:  Dump that piece of crap on eBay and get some money for it.

[spirantho]

What do you expect, it's an Amiga 4000.

Yeah, what you need is an Amiga 2000 because they're military spec.

(Sorry, couldn't resist)

The only real problem with the A4000 is the capacitors; change them and they'll be as good as any machine. The A2000 is the same - the caps don't leak as often, but they're still out of spec and should be changed now anyway.

[Vlabguy1]

The Caps Lock light not changing after several presses doesn't necessarily mean any one thing. I had the same problem when I needed to reflow Alice's solder.
Compare the Amiga's boot flicker with that of an A1200. The monitor should lose sync momentarily, but it will be for about a tenth of a second. If the monitor just immediately resyncs without losing sync it may be the same problem as I had.
In my case because the joint was dodgy on Alice, it would occasionally boot up. Also leaving it on for a bit longer and then Ctrl-A-A would reboot it.

Do you have an oscilloscope? Check for activity on the SIMM sockets to make sure RAM is being accessed. If it's not, then the machine is probably waiting for one of the custom chips to respond correctly.

The machine should boot fine with just the PSU and the monitor connected, by the way. The keyboard is also useful but not necessary. You don't need the floppy connected.

Also, what is the voltage of the +5V line? It should be over 4.9V on an unloaded motherboard, though it may sink as low as 4.7V when everything is connected.

If you have an SMT rework station, I'd recommended a quick flux and reflow just to be sure. That's what fixed my A4000 (after years of trying to diagnose).

I will try some more testing when I get home. I found it strange though when I took the bad floppy drive out connected to a good working A4000 and it would not boot.  One thing is for sure the Floppy drive is bad.  And on the A4000 that is not working I found a pretty major issue when I removed the motherboard, I will post pics this afternoon.

Rich
ny
Oh ..to all those that suggest I get rid of the A4000 for an A2000.. well I have several 2000's so I am covered.  Thanks.

[freqmax]

Why would a A4000 be so bad?

Anyway the click from the drive is caused by the OS asfair so the CPU is likely running and perhaps Paula/CIA. So checking the graphics related chips is a good idea. Btw, check power supply.

Do you have access to an oscilloscope?

[Vlabguy1]

Why would a A4000 be so bad?

Anyway the click from the drive is caused by the OS asfair so the CPU is likely running and perhaps Paula/CIA. So checking the graphics related chips is a good idea. Btw, check power supply.

Do you have access to an oscilloscope?

The click I hear in the bad floppy drive is mechanical.  It's the metal disk protector sliding open.  I think I will take a known good floppy drive and put it in the A4000 that is not booting..

Rich

[Vlabguy1]

Added pics.. Enjoy!!

[spirantho]

Just a hunch, but my years of repairing experience are telling me that the capacitor in the pic just may be a good place to start.