A4000 boot failure

[Shamus_]

Hey all. This has me frustrated. 2 days ago I managed to get my old 4000/040 to display the Workbench - which it hasn't done in years. I did get a DF1:?? notification on the WB  but I wasn't worried about it.

Anyways, I now find that it won't boot at all.  If I disconnect everything but the PSU and the '040 card I get the familiar "Insert Disk" logo. As soon as I connect a harddrive (any harddrive, even an old 2gig drive out of a Winbox), all I get is a dark grey screen. The drive spins up for a few seconds and then just sits there. There's no "click click" of the floppy drives either. Disconnecting the floppies doesn't make any difference. Nothing seems to initialise. I pulled all the fast RAM out thinking there may have been a problem with it but it didn't make any difference.

Can you guys think of a reason for this at all? The m/board  and '040 are in mint condition. No battery corrosion etc. I've tried 4 different IDE ribbon cables. Different ribbon cable for the floppies too. Different mices (mouses?). The only thing I haven't changed is the keyboard. Would that affect it? There's no blinking light at startup. Help, please?


Shamus....

[Shamus_]

Miloo wrote:
I had a similar problem ages ago when i got my A4000 but it turned out that my mobo wouldnt accept eide cables - i had to use the original old skool type ide cable. Also i did put the cables in the wrong way round! So the marked red strip on the cable goes to pin 1 on the mobo.

Well, I know the cable is around the right way. (Checked it and checked it and checked it). :-) I'm also using 40 wire ribbon cable which is what Ami uses and I'm stumped. I don't want to think that the IDE controller is shot/knackered. I had 2 different drives boot up the other day and now nothing works. Can you think of anything else?

[Shamus_]

TjLaZer wrote:
Also make sure IDE drives are jumpered correctly.  Some need Master, some no jumpers when used alone, etc.

Sadly, that isn't it either. The drives booted the other day without any problems. Without changing anything they now fail. I've tried everything I can think of and nothing works. Just a dark grey screen and that's it. It goes no further. *sigh*

[Shamus_]

Thanks for your input.  :-) I'll have a look at the things you've pointed out but I'm starting to suspect a serious problem with the m/board itself. I have another couple of A4000 boards here but they have a fair bit of battery corrosion on them.

I suppose once I check the things you've  suggested, the next option is to toss in another board and see if things work. If they do work, I might have to throw a carton of beer at a workmate to swap the batteries over for me. A little rubbing alcohol should clean things up in the meantime, shouldn't it?

[Shamus_]

1. Jumpers haven't changed since it booted up the other day.

2. Pretty pointless having a 4000 and not using the HD. I clearly remember playing Heroes' Quest on a 500 and swapping disks all the time. Not something I want to go back to. :-)

3. I've got one around here somewhere. It's not the harddrive that's failing. It's the hardware. It's 11pm here. As good as time as any to head out to the garage and pull it apart, I suppose.

[Shamus_]

An hour and a bit later......


I tried 3 different motherboards, 2 different '040 cards and an '030 card and tried 3 different sets of both fast and  chip RAM. All 3 m/boards exibit the same strange behaviour, that being if I remove the chip RAM, only about half the time do I get a green screen. Possibly a PSU problem? What do you guys think?  

[Shamus_]

Kin-Hell wrote:

Sounds very possible. Only a swap out will conclude!

Be real sure that processor card is well seated. They can appear "in", but arnt "in" sometimes. Do a visual with the CPU cards edge connector in relation to the Mobos Connector edge. Be sure they are paralell & fully mated. Thats MAXIMUM insertion...if you'll pardon the expression!

I have an ATX to Amiga A4KD Convertor here if you cant find another PSU. I'd like £12 for it + P&P. Excuse the "Sales Pitch" Admin, just trying to help! ;-)

Good luck!  :-)  

Apologies for the delayed reply. I had a blonde moment lasting several days.


Well, I've torn my place apart looking for the other Ami PSU and I can't find it anywhere. I dunno what the hell I've done with it. After swapping damned near every component in my 4000 I'm pretty much convinced that it's the PSU.

If your kind offer still stands, flick me a PM and we can work something out. Thankyou.

[Shamus_]

Have done and just did etc....  :lol:

I'm just about ready to have my 4000 put down if the psu thingy isn't the cause of the problem, even though I can't see anything obvious wrong with it. I gave the psu a bath the other day to clean the accumulated crud off the various bits inside but to no avail. Looking to grab another psu off ebay. A spare wouldn't hurt....

[Shamus_]

CLS2086 wrote:
Final solution : send it to repair at AmigaCenter

It's not a bad idea but the Heap-O-Crap™ would cost more than it's worth to freight to France and back from Oz.  I should have a new PSU for it in a week or so. If that doesn't work I might just scrap it as parts. :-(

[Shamus_]

Flash wrote:
Hi,

From a recent experience from one of my A1200's, Ihad a failure in one of the 3.1 rom chips which produced a similar occurrence, I tried a downgrade to 3.0 roms and my computer booted no problems. Therefore check your rom chips are correctly seated, especially as they tend to draw out from the socket holders over time.

Yours Flash      :idea:

A good idea but it's not the problem. If you look through the thread I've swapped out the motherboard with others and got the same result. All chips on all boards are properly seated and the PSU is the only component that hasn't been changed.

[Shamus_]

Zac67 wrote:
A word on electrolytic capacitors: Their tops must be absolutely flat. When they break the top bulges out, not always do they leak and very rarely rupture.

Open the PSU and check that for bulged caps, too. Don't touch anything inside, there may be hazardous voltages, even when disconnected from mains!

Check PSU voltages (under normal load), there shouldn't be more tolerance than 5%. Also try the multimeter set to AC to check for ripple in the voltage - more than ~100 mV isn't to good either (vary CPU load, floppy, hard disk access while doing that).

I'll have to get a mate of mine to do this as my skill with electronics is only surpassed by my skill as a photographer. .. which I will demonstrate shortly. The tops of the capacitors are all dead flat. No bulging etc. The one thing I did find after a close look was a white, dry residue on one of the larger capacitors. I have no idea if it was always like that or it's the source of the problem. Have a look for yourself here:

http://users.tpg.com.au/adsldxhe/piccy.jpg

[Shamus_]

Homer wrote:
Hi Shamus, did you try leaving the molex in the hard drive but taking out the IDE cable before booting up? That should load the psu without bothering the IDE bus........
Do let me know what happens  :-D

Heya mate.

I did try that but nothing changes. Remember that I've tried 3 different motherboards and they all do the same thing... that is if I pull all the RAM out, I don't get a green screen (CHIP RAM failure) when it tries to boot. The only things plugged in are the PSU, m/board and o4o card. That's it and the PSU is the only thing that remains constant.

[Shamus_]

Hoping to pick up another PSU next week. For someone with no electronics ability at all, how difficult is the hack? Is there a schematic around somewhere that I can toss at a mate of mine who understands it?

It's infuriating. My Cybervision card is sitting in its box unopened. I've also got a scsi card, network card and extra drives ready to go in once it's up and running. I dug up an old hub with a BNC port on the back so the Ami can slot into the rest of my network. B*stard of a thing.