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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Ronmor on May 25, 2005, 01:47:21 AM
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My 4000D was working fine until I tried plugging a cd rom drive on the IDE cable. When I powered it up I had no workbench screen. So I unplugged the drive and got same thing. I then unplugged the harddrive but no Rom screen.
I tried different Roms, a different power supply and also tried swapping out the small IC chip thats behind the Rom chips, plus tried a different cpu board. What else can I check? :-o
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Could be a lot of things. I always suspect the floppy drive cable first 'cause it's real easy to not plug it in right or accidentally partially unplug it and it won't boot. I had a hell of a time getting a cdrom installed recently given the tight spaces in the 4000D. It's real easy to unplug something accidentally or switch the cable around the wrong way. I suspect this is probably your problem. Try different combinations of the power connectors, maybe there's a break in one of the old wires. Also, make sure the power supply m/b connector is not grounding to the case beneath (leads are long and can penetrate the thin plastic beneath. There could also be corrosion somewhere (e.g. my buster socket was crappy and caused either no booting or dead Zorro slots). When you power it on, if you get a faint grey screen that's a good sign that she's not dead. Think like Mr. Spock and you should be okay, don't panic.
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Also check and make sure you didn't knock one of the memory simms loose. Those factory sockets are terrible.
Jeff
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Thanks for all the suggestion Argus & Jeff! Now the motherboard is out of the case and setting on my work bench with no cables or daughter board, still no go. I also tried different memory sticks. I thinking that I might of plugged the IDE cable in backward since it isn't keyed, if that was the case which chip would I replace? Any an all suggestion are welcome. :-o
ps. when I power up I get a gray screen, if I do a reset with the keyboard the screen goes red to gray to red to gray etc.
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IIRC red indicates a problem with the rom / kickstart. Tho I don't remember it would alternate between red and grey..
Try reseating all socketed chips, might help.
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You might want to read this:
http://www.nyx.net/~rdavis/AmigaHints2.html
1-2 pages down it describes the boot colors on the amiga...
To me it looks like a bad CIA chip...maybe?
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Thanks Mr. D of the Faith, but with the new 3.1 Roms I order from software Hut I get a gray screen with a reset.
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Thanks dawiper! I might try replacing the CIA chips.
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Ronmor wrote:
Now the motherboard is out of the case and setting on my work bench with no cables or daughter board, still no go.
Try bench testing with the daughterboard installed. I'm pretty sure it will not boot w/o the daughterboard in.
Regarding the rom sockets, try cleaning them with contact cleaner. Mine were dirty before and caused intermittent booting.
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I'm pretty sure it will not boot w/o the daughterboard in.
You sure ? I seem to remember my A4000 did.. Well before it died tho..
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Try a new power supply as the IDE CDROM may have just over loaded it and caused it to fail.
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@Ronmor:
I have a faint memory of the A4000 motherboard needing to be screwed into its case as it connects some of its groundplanes via the case metal.
/Patrik
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Not that it is of any help, but I have previously powered up a A4000 motherboard withput it being installed in its case and without the daughterboard.
Only 030 board and 2 MB chip installed and the computer booted. Could be I was just lucky though.
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I assune you have an 040. I think you need to have the cpu card seated prperly, even if it is just alittle unseated your machine wont boot: it happened to me
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I have experienced the same thing as doctorq in regards to being able to power up A4000 motherboards so far, without them being installed in the original, or any computer case for that matter. It seems that having to have the board grounded with the case in order to for it to work is an old wives' tale, after all. :-)
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Thanks eveyone, I tried all suggestions but I think it is the CIA chip there are two of them is that correct? If I try swapping out a CIA chip which one should I try first?
ps. I'm pleantly pleased with all the information I got from this site thanks again. :-D
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I think it is the CIA chip there are two of them is that correct? If I try swapping out a CIA chip which one should I try first?
I believe that a common trick is to swap the "odd" and "even" CIAs around. If one of them is faulty, then the Amiga will fail with a different problem.
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Thanks for info. Alx, but the CIA chips on the 4000D are surface mounted (I think) that is why I asked which one should I try first.
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@ Ronmor
Leave the Miggy off for a while and let the chips cool. Then place two fingertips of your left hand on the CIA chips (one tip per chip) and switch on with your right hand. The CIA that gets quite hot compared to the other one, is the faulty one.
At least that is how they found which CIA of mine was faulty all those years back.
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For a second I thought Red had come back... :-(
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For a second I thought Red had come back...
Guess he's still mad at us.
This is a method I've used in the past with some success.
It's a bit extreme but will give you a 50/50 chance of finding the bad CIA first try.
Use that "hot finger" trick to get a good guess at which is the bad CIA.
Cut the pins away from your choosen CIA and remove it from the motherboard.
A sharp xacto blade makes a good tool.
Power up see if you get a screen. Yes? You found the bad CIA, yea!
No? Drat, it was the other one.
Of course a good amiga repair center is always the best ;-)
Plaz
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@doctorq
Yes, I remember bench testing an old a4000 motherboard just on some antistatic plastic, it did boot fine. Guess that means I'm not one of the old wives.
@Plaz
In the true Amiga spirit, maybe we should start a petition to bring back Red. If enough people signed on, maybe he'd drop his C=128 long enough to post here.
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Thanks Plaz, X-ray & Whabang. I try the hot finger trick, sometime the best trouble shooting tools is common sense!
Where would a trouble shooter buy CIA chips. I looked at software Hut site but didn't see CIA for the 4000?
I was thinking wouldn't it be great if everyone that visits this site was in the same room full of Amiga hardware & software. :lol:
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arent all the cia chips the same through out the amiga range? its old tech i think it was even used on some old commodore models.. so maybe any old cia chip will do?
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no, the cia chips in the 4000 are small square plcc type chips, different from the larger dip style in the 500, 2000, 3000, etc. I think they're the same as the ones in the a600 and a1200.
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I think they're the same as the ones in the a600 and a1200
I know the CIA's are the same in the 1200 and 4000, not sure about the 600 snice I've never seen the inside of one. There was a vendor in Flordia I bought CIA's from, but I dont' think they're around any more. You might email softhut.com and amigakit.com to see if they have any stashed in the closet. You might also post for a non-working 1200 you can scuttle the CIAs from. I'll post or pmail if I see another source.
Plaz
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@Argus
In the true Amiga spirit, maybe we should start a petition to bring back Red.
I don't know, he was very sore when he left. Didn't even answer an email when I wanted to buy some thing. I see some of his ami/c= auctions on ebay, so he's still out there. I like to think he'll be back one day. But it did seem there were a few here that did enjoy sticking it to him. As long as that still exsist, he'll stay in they 40 colum/16 color pond I guess. :-)
Plaz
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My own experience tells me the CIA chips are not likely the source of the problem. CIA problems would manifest themselves as problems with sound or floppy access, followed by eventual lockups (as with my DOA A1200 board). The red screen of death is usually do to a failure in the CPU, ROM or RAM... Such as an improperly seated CPU card (which I see all the time as I am lacking the little plastic feet), the CPU itself, ROMs or loose SIMM. I've even gotten it when my SCSI card is loose.
PS: Benchtesting ANYTHING on antistatic bags is a BAD IDEA!! They're made of an electrically conductive material, which will cause short circuits across all of the pins along the botom of the board.
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Dawiper to the rescue.
Here's one source for spare parts:
http://www.amigashop.com/shop.php?k=64f22fd4ae33fe70bfea6e60c382fafd&s_2=&grp=2
Here's a link to their: "For foreigners" info.
http://www.datakompaniet.no/index_e.html
This is where I get all my Amiga stuff. They are ok!:)
The price is in NOK(norwegian currency). One cia chip equals $35.
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Dr_Righteous wrote:
PS: Benchtesting ANYTHING on antistatic bags is a BAD IDEA!! They're made of an electrically conductive material, which will cause short circuits across all of the pins along the botom of the board.
Really? I guess its a miracle I haven't blown up 10's of pc-motherboards + my a1200. If the bags was electrically conductive they wouldn't give much shielding for static electricity...
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They are a shield *because* they are conductive, they contain metal. Any electricity stays on the surface of the bag, not flowing to the contents.
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Thanks again dawiper. I reread that trouble shooting site that explains the colors on the boot screen and which CIA would be at fault, my problem is the U7/U300 CIA. :-)
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dawiper wrote:
Dr_Righteous wrote:
PS: Benchtesting ANYTHING on antistatic bags is a BAD IDEA!! They're made of an electrically conductive material, which will cause short circuits across all of the pins along the botom of the board.
Really? I guess its a miracle I haven't blown up 10's of pc-motherboards + my a1200. If the bags was electrically conductive they wouldn't give much shielding for static electricity...
AmiGR wrote:
They are a shield *because* they are conductive, they contain metal. Any electricity stays on the surface of the bag, not flowing to the contents.
Once again I spoke without doing some research.:-D Yes most are "metalized", and some are not. With some bad luck this could probably make trouble. Sorry about my incorrect statement.
From now on I will not benchtest amigaparts on such bags. I will however continue testing pc parts on esd bags. :-D