Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Tumbleweed on October 13, 2013, 09:13:44 PM
-
Hi All
My A3000T, which I've had for just over a year has been working fine, until last week. The machine from after about 10mins. Screen changed to dark grey, mouse, keyboard all not working. Tried to soft reset, didn't work.
So I switched it off. Left it for a minute or so and switched it back on. No good. Black screen, which in the past has indicated a CPU card issue. So I opened it up and wiggled the CPU card (CS MKII - 060). Nothing - black screen.
I then left it and went to work.
After about 10hrs switched off. I tried again, this time disconnecting the HDD from the internal SCSI controller. The machine booted to kickstart (40.68 ROMS). I then reconnected the HDD and tried again. Machine booted into workbench and was OK for about 5 mins and then the same thing. Froze - grey screen.
So I disconnected the HDD and tried to boot. No joy. Black screen and its been like that ever since.
In an attempt to fix it I have done the following:
1. Removed the CS MK II.
2. Reset jumpers for 030 mode as follows
J100 1-2
J102 2-3
J103 2-3
J104 1-2
3. Removed all expansion cards
4. Removed all internal socketted ZIP RAM.
5. Removed the HDD
I've checked and re-checked SCSI termination - external port is connected to a external CDROM and is terminated.
Anything else I could try?
The battery is still installed - the bad barrell type but there is no sign of leakage or m/b damage on the top-side at least. How can test the battery?
I do hope I can get this working. Its my main Amiga and took me 5 years to find.
Weed.
-
Check the caps if they have started to leek.
Check the PSU, unplugg it from the motherboard and connect it to a hdd and start it and messure the power output on the connector.
-
Check the caps if they have started to leak. They may be bowed, bulging, or have soldered connections that look dull or dull green.
Check the PSU, unplug it from the motherboard and connect it to a hdd to give it a 12 V load and start it and measure the power output on the connector, or carefully check voltages while still connected to give it a load on all pins.
Those are reasonable suggestions, but the battery is a good bet too; if it is not holding a charge, then it is dead and removing it will let you see damage underneath. Also reseat all the socketed chips, as heat and cold cause expansion/contraction and will mess up connections. Lightly sanding the pins on the chips will remove oxidation; remove any Zorro boards and de-oxidize them with a rubber eraser on a pencil -- cleanse with IPA afterwards. A toothbrush scrubing of the Zorro sockets and CPU connector will help there.
-
3000T has lots of traces under that battery. Remove it and you'll probably see your problem.
-
Guys
Thanks for your help. I've removed the battery - de-soldered it. What am I looking for, for signs of corrosion?
There is a small red circular washer stuck to the board where the top end of the battery was. Is this normal?
I've not pulled the other IC's and re-seated them I don't have a chip puller and I don't want to attempt levering them out with a screwdriver!
Weed
-
Can you post a good pic of the area?
-
Black screen is almost always trace damage from a leaky battery. 3000's caps never leak and you won't be able to clean your way back to good traces.
I have seen, far to many to count, 3000's die from battery damage. Never use barrel batteries, even if they are the green NiCad ones. Only use the coin types that don't leak, unless you don't install the diode and charge a nonchargeable battery.
You will need testing equipment and the schematics. It will be a long and detailed repair for the unskilled.
Your best bet is to find someone close to you that has experience fixing amigas and take it to them. Shipping will be an absolute killer since you own the heaviest Amiga Commodore every made, drive it to someone fairly locale and let them fix it. You may even want to try a local board repair shop that can xray the board and can fix the traces.
Sorry to see that happen to you. Black screens are the worst screen, all other colors are easier to repair.
Again Sorry.
Take it from someone who has over 20 years into 3000's, had 7 3000D's even owned a 3000T back in the day. Find someone who knows how to fix trace damage and get it fixed, and never use barrel batteries again...
-
I should have taken the battery out as soon as I received it. But I checked i tout and it looked ok. I guess looks are deceiving. This is going to be a job fixing as I don't think there is anyone in my locality that has nay experience of these machines. My best bet might be to trip the board out the case and ship it with power supply in a well packaged but lighter container than the case.
Does anyone know of anyone who could possibly fix it in the UK? I know Amigkit offer a caps replacement service, but do they do repairs? The only only other potentail is maybe AmigaCentre France - but I'm nervous about shipping it overseas.
I'll take pics of the board and post later when I get home from work.
Thanks for all your help.
Weed.
-
When my 3000T showed the same symptoms i sent The motherboard to Anthony Hoffman and he fixad it.
-
One last thing I forgot to mention, as Dan mentioned above remove the battery and neutralize the battery acid. Lots of threads on that topic. Be sure to be very through as the 3000 has 3 layers to the mother board and acid gets trapped in the sandwich layer in the middle.
Good luck!
Matt
-
One last thing I forgot to mention, as Dan mentioned above remove the battery and neutralize the battery acid. Lots of threads on that topic. Be sure to be very through as the 3000 has 3 layers to the mother board and acid gets trapped in the sandwich layer in the middle.
Good luck!
Matt
As Dan has said in the past, these batteries leak lye (KOH) and white vinegar will help bring the pH toward neutral (7) and prevent further etching away of the copper traces. Rinse with IPA afterwards.
-
Can you post a good pic of the area?
Its pretty hard to get a good close up. Here's the best I could get. Note the washer and the green cable running under the ROM's. Looks like it may have been repaired before?
Also U103 is empty. I've read that some CPU cards need this populated to work properly but I've never had a chip in it and the CS MKII worked fine for just over a year until now.
Do I need to populate it to get the A3000t to boot?
Weed
-
Yeah looks like traces are exposed so perhaps repaired previously. Awfully silly for someone to go through the repair and then install another battery that will eventually leak again.
-
Its pretty hard to get a good close up. Here's the best I could get. Note the washer and the green cable running under the ROM's. Looks like it may have been repaired before?
Also U103 is empty. I've read that some CPU cards need this populated to work properly but I've never had a chip in it and the CS MKII worked fine for just over a year until now.
Do I need to populate it to get the A3000t to boot?
Weed
that battery or another has definately leaked like kremlar said. you can go through with a multimeter and check for continuity on each trace.
do not put that style back,use a coin cell with diode as others have said.
-
You do not need the u103 for the MkII like You said, i have been using mine without any for almost 3 years now.
Cant even remember wich card that demands it.
-
You do not need the u103 for the MkII like You said, i have been using mine without any for almost 3 years now.
Cant even remember wich card that demands it.
Atleast Hardital PowerChanger 040 and PPS Mercury.
-
that battery or another has definately leaked like kremlar said. you can go through with a multimeter and check for continuity on each trace.
do not put that style back,use a coin cell with diode as others have said.
Thanks Mech,
I used to believe and use the green nicads and you helped me to switch over.
-
Yeah looks like traces are exposed so perhaps repaired previously. Awfully silly for someone to go through the repair and then install another battery that will eventually leak again.
I've had another good look at the board and its clearly been worked on previously. I removed the rom chip and the green line goes to one of the pins on the rom socket. Traces are also visibly shiny and the board appears to have been laquered.
I'll check for connectivity but where can I get hold of correct board schematics? Its a rev6.1 board?
Weed
-
Here: http://www.amigawiki.de/dnl/schematics/
-
I've had another good look at the board and its clearly been worked on previously. I removed the rom chip and the green line goes to one of the pins on the rom socket. Traces are also visibly shiny and the board appears to have been laquered.
I'll check for connectivity but where can I get hold of correct board schematics? Its a rev6.1 board?
Weed
You may not need a schematic(but you can download one), just use a multimeter set for continuity and check each trace from end to end to see if it has continuity- try and find vias or end points the traces lead to and check there. Its hard to get a good probe to register on vias since there is solder mask on them,but it can be done.
the typical repair you see there is common on the 3000t. most the time you clean and then tin the traces with solder to make sure they are intact,it may be a case that one of the repairs come loose or did not hold well.
i am guessing you will find the trace that has no continuity and repair it and hopefully you are back in business.
there is another thing that could of happened(lets hope not). acid inside the layers may have eaten something else.
i wish you luck on fixing it. a lot of persistence will pay off.
Mech
-
Thanks Mech,
I used to believe and use the green nicads and you helped me to switch over.
You are welcome.. the NIMH version of the barrel batteries leak just like the nicads also.. i tried them many years ago and one in the 3KT went fuzzy in under 5 years.Luckily no damage..
Avoid the Nicads and Nimh in my opinion.. If a coin cell cant be installed,leave the battery off. There are utilities to get the time from the internet if the 3kt is online.