Thread: The RamWall...
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Old 05-10-2007, 01:33 AM
Grant Stockly Grant Stockly is offline
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From: "logjam" <g...@cmosxray.com>
Newsgroups: sci.electronics.basics
Subject: Re: Wall of RAM
Date: 26 Jan 2006 00:23:02 -0800
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I was soldering the 14th board on Tuesday. After a little over 600
LEDs I found that they were ALL in backwards!!!! : ( I don't have any
spare boars. At least 300 of the LEDs will need to be desoldered (but
I have a nice station so it shouldn't take too long). Its easier than
it sounds since I spray painted the boards black. Once I "think" I
have the board orientation right I was just blindly pushing them in.
Soldering 10,000 LEDs at 1000 a day tends to do that to you.

At this point I am VERY sick of the 20k LED project. So I decide to
visually (lighting the LEDs) test the 13 completed boards of 990.

I found one other board where I did 32 rows of 30 correctly and put one
row of 30 in backwards.

The other most common defect was soldering one pin and not soldering
the other.

I found that most of my brother's solder joints were cold, so I went
ahead and reflowed about 3 boards of 990 just to be safe even before I
did a test lighting.

If I solder one board Thursday and one board Friday I will have 3
boards for Saturday. At peak efficiency it will take 12 hours of solid
soldring to do 3 boards of 990. I have to get them done by the 28th to
win that bet. ; )

My next project is to make a set of PCBs for the Magic-1 TTL computer.
I think that even better than an Altair driving the display would be a
TTL computer.
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