29 March 2011, 14:36 | #1 |
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Has this A500 RAM expansion been butchered?
I bought my first ever Amiga (an A500) the other day, and it came with a 512kb RAM expansion, but it doesn't work. After taking a look at it, it appears half of the components have been desoldered off. Can anyone confirm this for me? Or is there perhaps some crazy chance that this is how it's supposed to be, and there's just something else wrong with it?
Here's a couple of photos (apologies for the camera-phone quality): Thanks for taking a look! |
29 March 2011, 14:53 | #2 |
The 1 who ribbits
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probably the circuit for the clock
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29 March 2011, 15:04 | #3 |
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verify capacitor and bridge
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29 March 2011, 15:24 | #4 |
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This is what I thought, but there doesn't seem to be a pattern for a coin battery holder, which I believe they normally have.
I'm sorry, I don't understand. Are you saying that's what has been removed? If so, what are they, and does the RAM no longer function without them? Thanks for your replies. Last edited by Bead; 29 March 2011 at 16:19. |
29 March 2011, 15:34 | #5 |
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remove capacitors for test and verify jumper (sorry no bridge-translate error)
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29 March 2011, 16:51 | #6 | |
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Quote:
And according to the manual, removing the jumper disables the RAM. |
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29 March 2011, 16:57 | #7 | |
PSPUAE DEV
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You would definately see silver not gold if the components were there originally. |
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29 March 2011, 17:06 | #8 |
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It definately looks like components have been desoldered as there are erratic blobs of solder on all the holes, but maybe that's what it's supposed to be like. I'm not sure. I'll try to borrow a decent camera and take some better photos when I get home from work later.
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29 March 2011, 17:09 | #9 | |
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29 March 2011, 17:12 | #10 |
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It could be they were never there, meaning this was just a cheaper clockless version of the same expansion. The battery (3.6V barrel style) would go into the large rectangular area where it says BT1.
I agree, the soldering looks a bit shoddy at the empty pads, but it could be that this was just a low quality piece of HW. :-) |
29 March 2011, 17:28 | #11 | |
PSPUAE DEV
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Quote:
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29 March 2011, 17:45 | #12 |
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Seems that clock area is not populated at all (or parts are removed) - probably still can be used as normal RAM expansion.
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29 March 2011, 17:59 | #13 | |
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Quote:
Thanks for all the replies so far. Hopefully I'll get some better photos up soon. |
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29 March 2011, 18:46 | #14 |
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perhaps one of ram chips is defective.
or connector is bad. iirc, KS2+ could show 'board defective' screen. not sure if that would work on this kind of expansion, (i think it did on A590) |
29 March 2011, 19:27 | #15 |
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Board defective is only for Autoconfig devices.
This RAM expansion is not Autoconfig, it is instead detected by exec.library's RAM checker routine. If it detects no RAM or bad RAM, it simply doesn't add it to the RAM pool. |
29 March 2011, 20:35 | #16 |
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I've managed to take some more photos with a better a camera, although the quality still isnt as good as I was hoping.
First, here are the each side of the RAM chips up close (some are out of focus unfortunately): http://i.imgur.com/1R1CB.jpg http://i.imgur.com/ydoIX.jpg And here is the whole unit from above: http://i.imgur.com/WGxhk.jpg (I figured the photos would be too large to embed). I'm thinking I might just try to resolder some of the dodgey looking pins, but I'm not sure if it'll do any good. |
29 March 2011, 20:52 | #17 | |
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29 March 2011, 20:54 | #18 |
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Strange - i think that someone modify this board (repaired?) - memory IC are from IBM (quite rare) and some IC's legs looks weird (slightly bended?) IMO the best is replace all components based on many similar memory expansions...
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29 March 2011, 20:57 | #19 |
PSPUAE DEV
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I think it was repaired, didnt work, so all the clock stuff was removed and this board sold on? as working?
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29 March 2011, 21:03 | #20 |
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