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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: marcfrick2112 on November 16, 2009, 10:44:30 AM
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Greetings,
Well, as my sig. suggests, I have a currently non-working A4000T. I read online tonight, that a missing or disconnected ground wire on a 4000T's A/V module could keep the machine from booting. Anyone have any info?
I do recall the ground wire breaking off a while back, but I was so worried about cleaning contacts,
replacing the PSU (twice) etc. that I never thought much about it....
So, if the missing ground wire could be a problem, anyone have a good pic they could send, that shows where the wire is attached to the A/V module? What would the symtoms be, if this was the 'thing' that was messing it up?
I'll try to list symptoms/specs best I can, since it's from memory...
A4KT shows back screen most of the time, sometimes on a cold boot it'll boot up OK, if I have only main HDD connected. Tried removing all cards, cleaned contacts, etc.
AT A4000T,Athena 400W PSU, CS Mk-3/128MB, SCSI CD + CDR on CS, 500Mb + 3 Gb HDD on int. SCSI... don't even remember if SYS: is OS3.1 or 3.9... couldn't get it going with either...
Any advice would be welcome....
Hope to post more useful info. later, after the Beck's beer wears off... :drink:
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Make sure your jumpers on the back are set correctly... on mine (an Amiga Technologies A4000T) the label is wrong, and describes the jumpers as the *opposite* (upside-down) of what they really are. System boot-up time will take forever if configured to match the label.
Have you checked/removed/replaced your battery? NVRAM on these things can be weird, and seemingly can keep the babies from booting.
Be careful about what is attached to the IDE bus.
I tried to get a picture of where the ground wire is connected on mine, but the room is dark and it looks like I would have to pull out the A/V board. If I recall correctly (and can see in the dark), it is attached to one of the audio-out jacks.
- t
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".....Have you checked/removed/replaced your battery? NVRAM on these things can be weird, and seemingly can keep the babies from booting...."
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Not on an A4000T. It can boot just fine with no battery at all.
Also: the A4000T can boot with that A/V wire disconnected.
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".....Have you checked/removed/replaced your battery? NVRAM on these things can be weird, and seemingly can keep the babies from booting...."
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Not on an A4000T. It can boot just fine with no battery at all.
Presumably, with no battery, then no NVRAM. Hence no problem.
With battery, possibility of corrupt NVRAM, hence possible problem.
Yeah?
- t
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Check if the disks module is attached properly, A4000T doesn't boot without disks module.
Failing that I don't know, maybe take off everything and see if you get the insert disk screen from the rom.
Jumpers on your scsi HD's and disks module could also make it wait a whole bunch of time or not at all...
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Trilobyte you are thinking of A3000 instead of A4000T.
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Trilobyte you are thinking of A3000 instead of A4000T.
Yep. There's no NVRAM in a 4000T.
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This ground..as in all grounds are very important in the electric/electronic world :-). Not sure if the lack of this ground would prevent the machine from booting. Its been a long time and I seem to remember things going wonky with this ground being kinda of loose but thought that might have only caused some audio crackles..
I can however attest to the fact that the machine WILL boot and run just fine with out the battery installed. I removed the battery on my main 4000T many years ago and all seems fine other than having to set the time/date on boot up..
Rich
ny
*** PM me if you need that pic***not home at the moment
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Thanks everyone for the advice!
I pulled the 4KT's A/V module tonight, and still can't see where the ground came from, so Vlabguy1, PM sent :)
It would be Soooo nice if I could get this beast running again ...
Again, everyone thanks .....
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Dude, the A4000T will boot without that ground wire connected. You must look elsewhere to find the problem.
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Agreed the Machine will boot withOUT das gnd wire attached(as stated above)...
I just sent the OP some pictures of my 4000T.
Rich
ny
Dude, the A4000T will boot without that ground wire connected. You must look elsewhere to find the problem.
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Hey Rich. Thanks for the pics!
X-ray: Dude, OK, just trying anything I can think of to get my 4000T going....
sigh....
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Have you done a complete strip down of the Miggy? I mean take everything out of the case, like so:
http://www.amiga.org/gallery/index.php?n=2695
You can then inspect the whole mobo (front and back), clean all the slots. Do you have another accelerator board to try?
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Marc,
I do suggest you check the capacitors on the A/V board for leakage and corrosion. I posted pics on here of my A/V board with leaky caps. Once you check, them you may as well check the disk module and the motherboard. I found a couple on my MB, although not quite as pronounced as the leaky caps on my A/V board..The problem might be deaper than just your A/V board.
Rich
ny
Hey Rich. Thanks for the pics!
X-ray: Dude, OK, just trying anything I can think of to get my 4000T going....
sigh....