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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: DirectorSG on April 10, 2013, 08:02:22 PM
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Hi All, I'm a novice with Amigas and I could really use some help.
A few years ago, I bought an A4000, an Amiga monitor (not sure of the model number), a Video Toaster 4000, two Personal TBCs and a CDROM drive, because the 4000 didn't come with one and the installers for the Toaster were on a CD. I opened up the A4000 and the battery was corroded. By Google search, I figured out that the best solution was to just cut it out, and the system ran fine...but I couldn't get the Toaster to work. The seller assured me many times that the Toaster was fully tested and it worked. So, I put it in my storage closet out of frustration. Last year, I decided to take it out of storage and work on it again. This time, I bought an IDE/CF card interface with a 4GB card and ran the A4000 on that instead of the stock hard drive. I STILL couldn't get the Toaster to work, and it went back in the storage closet. This week, I watched the documentary The Deathbed Vigil, and was inspired by the stories and camaraderie of the Commodore workers to really give it a try again. This time, I've spent days thoroughly going through the problems I'm having with this system. Here's what I've come up with:
1. There's a problem with the RAM. I have four SIMMS in the machine. There are three 4MB SIMMS, and one SIMM that I'm not sure of the size. When I open up WorkBench, it says that I have, "1,6xxx,xxx graphics mem, 0 other mem".
2. When I boot up the system with the Toaster installed, I get a blank screen. Nothing happens. Neither the CF card nor the stock hard drive will boot with the Toaster installed. I take it out, and it will boot up fine into WorkBench with either the CF card or the stock hard drive. I removed the analog board from the Toaster to make sure all the jumpers underneath the analog board were set correctly, and they were, but the chip on the analog board popped out when I removed it. I put the chip back in place before reattaching the board. Also, I connected a camera to the first input and monitors to the Preview and Main Outputs. The camera shows up on both of them with the power on, so the Toaster is working in some capacity, the system just refuses to boot into WorkBench or into the Switcher program.
3. I tried the Personal TBCs without the Toaster installed. I installed them and the software and everything worked fine. When I tried to run the Toaster software, it said "could not obtain FAST memory" and froze up.
I Google searched all of these problems and I can't find a clear solution. Is there a bad jumper setting? Something that needs to be reseated? Do I have bad RAM? Please help me solve this, because my frustrations have reached the point of just eBaying all of this stuff, which I don't really want to do.
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The 4000 battery acid ate the traces for the memory. forgive the pun the 4000 is toast!
The toaster requires at least 8 megs of fast memory and 1 meg of chip mem (two is better)
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Do check the traces around the battery with a multimeter... however, that's not definitely the problem.
Take out all the SIMMs except for the 2MB one towards the centre of the board - this is the Chip RAM which is necessary to run at all. Now (with the power off, obviously) put one 4MB SIMM into the socket next to your Chip RAM. Boot up the machine and check how much memory you have. If it's 4MB Fast RAM, put it in the "Working RAM" pile, otherwise if it's zero, put it in the "Suspect RAM". Repeat with the other three.
If any of them give 4MB Fast RAM, your board is good, and you have a bad SIMM. if none of them give any Fast RAM, your board is bad.
All is not lost, however... it's probably just a matter of finding the track that's not connecting any more and sticking a wire on it to make the connection again.
Even then, if you can't fix it, there's still hope! Your board is working with its Chip RAM, and that's most important. All you need to do is to buy an accelerator with local RAM (pretty much any accelerator does) and bingo! you have a full complement of RAM again (probably :) ).
It's not over yet, anyway, so don't despair! You've done the most important thing (removing the battery) and the machine is basically working, so it's just feeling a bit dodgy, not dead!
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I ran the memory tests, and it looks like it might be fried RAM sockets as suspected, but the chip RAM socket is OK... I put each SIMM individually in each of the four sockets and got "0 other mem" on all of them. Sometimes I had to keep reseating them, or else I'd get a purple screen or a yellow screen.
I don't have a lot of experience with Multimeters, although I do have one. I usually use it to test batteries. I'm not even sure where to put the positive lead and what proper voltages would be.
Given the prices of accelerators, it might just be cheaper to get another A2000/3000/4000 to use the Toaster and the Personal TBCs...how much can I expect to sell an A4000 with fried RAM sockets?
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I ran the memory tests, and it looks like it might be fried RAM sockets as suspected, but the chip RAM socket is OK... I put each SIMM individually in each of the four sockets and got "0 other mem" on all of them. Sometimes I had to keep reseating them, or else I'd get a purple screen or a yellow screen.
So it looks like I may have to get my hands on another A2000/3000/4000 to use the Toaster and the Personal TBCs...how much can I expect to sell an A4000 with fried RAM sockets? Is that something that can even be replaced?
Like the above poster said, nearly all A4000 accelerators include the option to add fast memory, or you could try something like ZorRam, etc. You've still got all kinds of options! Plus I'm sure someone else will come along soon and tell you how to repair those ram socket traces. ;)
http://amigakit.leamancomputing.com/catalog/product_info.php?products_id=958
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Given the prices of accelerators, it might just be cheaper to get another A2000/3000/4000 to use the Toaster and the Personal TBCs...
Yeah, but you'll get a GIGANTIC performance increase by installing a good accelerator. A 4000 needs an accelerator board with RAM. To the point, I'd almost say it can't really live without it. The stock RAM access on an Amiga 4000 is... how shall we put it? COMPLETELY CRAP.
Of course, you don't really know if the RAM access is the only thing wrong with your motherboard... (The TBCs don't really use the Amiga for much beyond power, so they're kind of a bad test case.) There may be some other damaged traces that the Zorro III slots need to function correctly. That would be my only worry with saying just get an accelerator. Even then, though, if you're actually going to use the system any, you'll probably want an accelerator with local RAM, regardless of the motherboard you're using.
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I ran the memory tests, and it looks like it might be fried RAM sockets as suspected, but the chip RAM socket is OK... I put each SIMM individually in each of the four sockets and got "0 other mem" on all of them. Sometimes I had to keep reseating them, or else I'd get a purple screen or a yellow screen.
I don't have a lot of experience with Multimeters, although I do have one. I usually use it to test batteries. I'm not even sure where to put the positive lead and what proper voltages would be.
Given the prices of accelerators, it might just be cheaper to get another A2000/3000/4000 to use the Toaster and the Personal TBCs...how much can I expect to sell an A4000 with fried RAM sockets?
@dirSG
Even though the amiga boots, without fast memory...it's very limited
and while the accelerator fix is tempting...
The battery acid will keep eating at the traces
STOP the acid burn first.
I have seen only one 4000 motherboard fixed by a hard core DIY type.
If you are not that hard core the motherboard will die.
Just my two sense.
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@dirSG
The battery acid will keep eating at the traces
STOP the acid burn first.
I have no idea how to do that, or what would visually indicate where battery acid would be eating away at the traces, but I'm willing to learn if someone knows.
I think the best short term solution is to get a ZorRAM card as Mike suggested. It's reasonably priced and most likely cheaper than trying to buy another system. If it turns out that there are more problems and I still have to buy another system, the ZorRAM card would still be useful. Thanks for the advice all.
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Use a solution of vinegar and baking soda to neutralise the ph and then I would clean the entire area around where the battery leak happened using isopropyl alcohol and a Q-tip then visually inspect the traces for any signs of damage / discoloration. Also clean the contacts on the SIMM sockets with isopropyl alcohol.
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Thank you very much, I will try that.
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Use a solution of vinegar and baking soda to neutralise the ph
Questions about this:
What kind of mixture do I need for the vinegar and baking soda? Do I also apply that with a cotton swab? Should I wait for it to dry before applying the alcohol? Also, how long should it take to dry before I can power on?
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First, you should be sure that it is a battery acid problem or capacitor, there is one (C192) near the chip U891 in charge of the ram....
If it is, it's highly possible that your ram problem is related to that.
Take a good picture of the battery area and post it here if you are not sure.
We will be able to tell you if the battery is faulty... A very small battery leak can cause big trouble if it is not good cleaned...
You could also try with a knowing working set of ram if no leak is detected and check continuity with a multimeter to find an open track.
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I jumped in and took a guess on the baking soda/vinegar solution. Cleaned around the battery area, the C192 cap with the solution and then around all those areas plus the RAM slot contacts with rubbing alcohol. Here are before and after pics:
Before:
(http://i.imgur.com/QncmTVj.jpg?2)
(http://i.imgur.com/TQi3Z2L.jpg?2)
(http://i.imgur.com/gzs3wtm.jpg?2)
After:
(http://i.imgur.com/xKa9jb7.jpg?2)
(http://i.imgur.com/Bn5ac3H.jpg?2)
(http://i.imgur.com/OmZtA8a.jpg?2)
I put the RAM back and started it up. When I put a SIMM into the slot next to the chip ram (labeled Bank 0), I get a purple screen. With that slot empty and the SIMMs in the other three slots, it still says "0 other mem".
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What does the underside of the motherboard look like?
Rich
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I haven't disassembled the 4000 that far. I would only take the motherboard out of the case if it were necessary for a repair.
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I haven't disassembled the 4000 that far. I would only take the motherboard out of the case if it were necessary for a repair.
@dirSG
From the pics, there's battery stains across to u911 and back past the caps
From what I see, this is a major repair in the making. That green stuff is all bad.