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Amiga 3000, Dead? Please dont say so :(

sev

Experienced Member
Joined
Mar 30, 2014
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132
Location
Los Angeles
I recently acquired an Amiga 3000. The guy I bought it from told me the battery damage was pretty extensive.

The pictures below are more or less how I got the box. I just cleaned the corrosion off, but the top layers of the board had already flaked away by the time I got to it. It looks like the previous owner physically forced the battery to snap off causing all this damage to the PCB. Very aggravating to see.

The other thing is the system looks like its missing chips. It had no kickstart rom, so I grabbed the roms v3.0 roms from my 4000 and threw them in, no dice.

When I turn it on, the VGA monitor comes up, black creen, the power LED comes up solid, no flashes whatsoever.

Along with the roms, I popped in a a3640 to see if it would have any life... nothing. same difference.

What else can I try? There is no SCSI drive connected, would that make a difference?

Pics of the motherboard, are there some RAM chips missing? It is bare on the bottom right where it has sockets from U850D to U857D.






Before cleaning: :( :( :(




After cleaning : :( :(





How much damage is there, is this fixable? I feel like the corrosion ate through multiple layers of the board.

HELP!!
 
Can't see the pics?

Anyway, the corrosion can always be fixed repairing all the damaged tracks following the schematics. I've recently done the same with my A3000.

It can boot without HD but you'll need some kind of ROM for sure. To use 3.0 ROMs you'll need to configure some jumpers in the machine.
 
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Amiga 4000 ROMs won't work in a 3000. They lack the required SCSI support.
 
The ram at the left is chip ram, the ram at the right is fast ram. The eight empty socket at bottom right are normal. If you don't have any ZIP fast ram, you can switch 8 DIP ram chips from the sockets at the left to those at the right, giving you 1MB of chip ram and 1MB of fast ram. Since you have 8 ZIP chips at the right (giving you 1MB or 4MB of fast ram, depending of the chips installed), it's ok to have all 16 DIP ram chips to the left, giving you the maximum 2MB of chip ram.
Just in case you don't know: chip ram can be accessed by CPU and special chips (denise, agnus, etc.) and fast ram can be accessed by the cpu only. An amiga can run with chip ram only, but not on fast ram only, that's why 8 DIP chip ram are soldered on the board, you can't move them.

Edit: corrected the size of ram.
 
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First, you need A3000-specific ROMs. You technically could use A2000 ROM, but don't do that. Get the correct ROMs, and hopefully you don't need a ROM tower, because you haven't got one. I can't read the rev number, and I don't remember any of the rev numbers, but that would allow someone to tell you if you need a ROM tower or not.

Second, pull all the socketed RAM, and boot the machine. You will get a specific screen color indicating a problem if there is one.

I would do that before I try and repair the motherboard.
 
Back when I had an A3000, it had some battery damage similar to that. I ended up replacing the sockets for the chips for the Denise and Paula around the affected area and that was enough to get it running again.

It looks to me like you're missing the Kickstart ROMs, which you'll need at a minimum.
 
looking at your pictures unless you know how to lift those 7474 and 7404 IC's you cannot asses the full extend of the damage.

Your missing FastMem that can be helped by carefully removing the socketed DRAM chips, and placing them in the FastMem sockets.
Or placing ZIP's into the respective ZIP sockets.

BTW when lifting Chips always check for damaged pads and please use a Socket instead of directly soldering the IC's back in I expect the Capacitor by the 7474 be be disconnected and some of the traces to be missing in the area.
When that is the case use laquered wire to fix that problem.
 
Your missing FastMem that can be helped by carefully removing the socketed DRAM chips, and placing them in the FastMem sockets.
Or placing ZIP's into the respective ZIP sockets.

The DIP sockets for FAST RAM are in the same RAM bank as the first row of ZIP chips, so it only makes sense to use them if you don't have any ZIP chips. It's desirable to have the full 2Mb of CHIP RAM anyway, I wouldn't remove those.

Either way, it's best to not start changing things until you know the extent of the damage.
 
First, you need A3000-specific ROMs. You technically could use A2000 ROM, but don't do that. Get the correct ROMs, and hopefully you don't need a ROM tower, because you haven't got one. I can't read the rev number, and I don't remember any of the rev numbers, but that would allow someone to tell you if you need a ROM tower or not.

Second, pull all the socketed RAM, and boot the machine. You will get a specific screen color indicating a problem if there is one.

I would do that before I try and repair the motherboard.


Thanks for all your info, I do have a a2000 here, I want to try to pop the ROMs in to see if it will work, obviously if it does Im willing to buy the correct roms. So just to confirm youre saying the a2000 roms would work? If i pop them in should It show me a color code if there is something wrong?
 
First, you need A3000-specific ROMs. You technically could use A2000 ROM, but don't do that. Get the correct ROMs, and hopefully you don't need a ROM tower, because you haven't got one. I can't read the rev number, and I don't remember any of the rev numbers, but that would allow someone to tell you if you need a ROM tower or not.

Second, pull all the socketed RAM, and boot the machine. You will get a specific screen color indicating a problem if there is one.

I would do that before I try and repair the motherboard.

what is a rom tower???

The board revision is 8.9 I believe
 
Thanks for all your info, I do have a a2000 here, I want to try to pop the ROMs in to see if it will work, obviously if it does Im willing to buy the correct roms. So just to confirm youre saying the a2000 roms would work? If i pop them in should It show me a color code if there is something wrong?

No, A2000 ROMs could work, but it's not a simple matter of just plugging one in. And, it may only work with release 1.3 and earlier ROMs. It may only work with early revision A3000 motherboards, and it may not work at all. It's quite possible no one ever actually did it, but, the original A3000 was designed so A2000 ROM would work with some modification or something. IIRC, that's the original reason there were 4 ROM sockets. But, also, it would make perfect sense that the A2000 ROM capability went away when the ROM tower came about or went away.

what is a rom tower???

It's a board that plugs into the ROM sockets and has sockets for ROM chips on the bottom. I have an early A3000UX that requires this, but it is my understanding that boards even earlier than mine don't require them.

There are pictures of a ROM tower here.

The board revision is 8.9 I believe

Ten years ago I could have told you everything you would want to know about that board. Unfortunately, I just don't remember that stuff anymore. My guess is that you don't need a ROM Tower. But, it's only a guess, and it would be best to confirm that with someone else who has an 8.9 board.
 
No, A2000 ROMs could work, but it's not a simple matter of just plugging one in. And, it may only work with release 1.3 and earlier ROMs. It may only work with early revision A3000 motherboards, and it may not work at all. It's quite possible no one ever actually did it, but, the original A3000 was designed so A2000 ROM would work with some modification or something. IIRC, that's the original reason there were 4 ROM sockets. But, also, it would make perfect sense that the A2000 ROM capability went away when the ROM tower came about or went away.



It's a board that plugs into the ROM sockets and has sockets for ROM chips on the bottom. I have an early A3000UX that requires this, but it is my understanding that boards even earlier than mine don't require them.

There are pictures of a ROM tower here.



Ten years ago I could have told you everything you would want to know about that board. Unfortunately, I just don't remember that stuff anymore. My guess is that you don't need a ROM Tower. But, it's only a guess, and it would be best to confirm that with someone else who has an 8.9 board.


thanks for all the info.

I yanked off all the ZIP chips and fired it up, no diagnostic screen came up... So sounds like if I want the roms I need to take a gamble and order actual a3000 roms? given the extent of the damage Im not sure If I want to take the gamble without SOME indication that the board still works.
 
Unfortunately the only way you'll get it to do anything at all is with a set of A3000 ROMs. Any A3000 Kickstart ROMs will work for diagnostic purposes.
 
Seems like there's still some residue on the board. Go to a chemistry supply store and ask for a solution of " Iodophor " which is iodine and phosophoric acid. Get a clean turkey baster or other syringe like device and use that to apply some to the board. Leave it on there for ~5-10 minutes, then clean it off. Take the motherboard then and throw it in the dishwasher with the hot water wash turned off and the heated dry and a little bit of Dawn in the detergent reservoir. Take it out once dry and put it in your water heater room and leave it there for 24 hours. Then use a hair dryer on high, ensure board is COMPLETELY dry.

I used this to resurrect an A2000 years back. After doing this, I repaired the tracks by bridging the damaged sections with wire. A real pro would repair the tracks by putting in copper and putting some sort of protectant on it, but I'm not that good at soldering.
 
Hi, not sure what you used to clean the board but the key is to nutrealise the acid from the battery. I have brought a few A2000s back from the dead and find the best corrosion stopper is pure lemon juice followed by a good rinse, clean and dry.

Have to say, the acid from your battery looks to have had a pretty catestrophic effect, most I have had the battery has eaten its way through tracks and occassionaly pin solder and a little corrosion to any bare metal its come up against but yours looks to have worked its way through the whole PCB almost!? I would guess for the amount of hours you would have to pay someone to put that right it would be more economical to just source a replacement board?

Classic Commodore design of putting a little barrel of acid right next to key components lol... on the A2k its 10mm from the 68000 and I just caught my A4k in time as that was 10mm from the SIMM bank... genius :)
 
You mentioned too that you tried this with an A3640. This board has a built-in processor. Have you tried it in that config? Make sure the jumpers are set right for the internal CPU.
 
You mentioned too that you tried this with an A3640. This board has a built-in processor. Have you tried it in that config? Make sure the jumpers are set right for the internal CPU.

Those jumpers are very important, but it won't do anything without ROMs.

Interestingly, an A3000/25 runs about the same speed with the stock CPU as with an A3640. And, the rather large amount of heat introduced inside that small case by the '040 is very problematic.
 
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