HELP! My Amiga 4000 isn't working!

[Invisix]

Ok, I took out the CPU card, and end up with just a black screen on startup, so I know the CPU card seems to be working correctly, since when it IS plugged in, I get the colors on the screen.

If this makes any difference, the Amiga 4000 is a Commodore Amiga, not Amiga Tech.

[Framiga]

Invisix . . . i don't know, how much time you are around here but (if i were you) i woult take in HIGH consideration, the suggestions given by Thomas ;-)

ah, obviously if i were you.

[Invisix]

Oh I know, i'm not doubting Thomas, I just don't recall the power LED on my Commodore Amiga 4000 ever being dim then brighter, or even blink. I know the A1200 does that by default, if I remember correctly.

All I know is I get a Red screen, which goes away after roughly 5 or so seconds, then goes to a blank screen. No floppy activity, IDE light stays lit (only when CD-ROM is connected), and the HDD won't read anything either.

[Thomas]

The power LED is the main health indicator of any Amiga computer. On the early models (A500, A2000) the LED was completely controlled by the processor (i.e. it stayed completely dark until the Kickstart switched it on) and on the later models (A500+, A1200, A4000) only the brightness is controlled by the Kickstart. The power LED is also directly connected to the low-pass sound filter. So if some music program switches off the sound filter, the power LED becomes dark/dimmed, either.

Given that the not correctly working power LED has something to do with the problem and assuming that the crashes are caused by random interrupts, I would guess that one of the CIAs is dead.

Unfortunately on the A4000 most chips are soldered to the motherboard. On an A500 you could easily swap the CIAs in order to test it.

Another point to look at is the power connector on the mother board. People have reported that over time some of the wires burn out, indicated by the insulation becoming black. Perhaps, if one of the wires has a loose contact now, it would cause random crashes, too.

Bye,
Thomas

[Invisix]

Yeah, i've done everything you all have said. Nothing seems to be helping it, the Power LED doesn't brighten at all, it just stays steady the entire time.

I checked the PSU, nothing blackened or singed.

By the way Thomas, it's not random, the system won't boot at all, all it does in turn on, the screen is instantly Red then blank, and sometimes goes from red to yellow, then blank and that's that... however if I leave it on in that state, it'll turn different colors such as purple, orange, etc... and sometimes I will see streaks of white lines at random.

Some folks have told me it's just bad Kickstart ROM chips.

[gdanko]

I had a similar problem with an old 4000. I took EVERYTHING out.. re-seated all the chips, crystals, etc..

Blew the dust out with some compressed air.. and voila, it's back alive.

[Argus]

For my money, you've got a bum power supply.  Thomas is right about the LED brightness thing, believe him.

You could try taking apart the power supply (if you don't value your life much) and look on the underside of the pcb for the p/s.  I have repaired a couple where there were lead solder traces that had deteriorated over time ending up with a machine with symptoms like yours.  I suspect the p/s most of all because you say the machine was working before you put it in the closet.  You should also make sure that the power supply connector on the bottom of the m/b is not grounding to the case (this causes all kinds of whacko problems).  A little extra plastic in this area is a good idea.  A dead but recently moved machine can also be symptomatic of a bad cpu card contact.  Those little pins on the cpu slot can drift over time so the cpu card doesn't make good contact.  Just my five cents worth......

[tonyvdb]

Yes, The power light does do the dim to bright stages. I just started up my A4000d and it goes from dim to bright. I had my Amiga fail before and I needed to get another 3640 board to fix it but I never had the coloured screens it just wouldent boot and only showed a grey screen. Works great now.

[TjLaZer]

I would contact Jean at Amiga Center in France. He does a great job in repairs!  He has repaired a A4000 and two A600 motherboards for me and the time it took to send them off and have them back on my doorstep was 3 weeks!  From what I remember he charges around $100 to fix the A4000 and around $50 for the A600s.  This is a good deal as a used A4000 MB or A600 costs $150+ (USA)

[Tomas]

Have you checked the psu?? As in checking that it outputs the right voltage and so on... It could be a dried out capacitor or something, which can happen with old hardware being unused for quite some time. Lets hope it is the psu and not some capacitor or corrosion in the amiga itself, as the psu can be easily replaced.

Good luck on finding the error.

Edit: does the hard drive itself spin up??

[Invisix]

Yes, the hard disk itself does spinup.