A few other points...
Loved the tear down of an old friend, the TRS-80.
Tarnished pins is quite common on old chips - a common sight on old digital clock chips. It has to do with the plating on the pins... maybe some had silver content.
The shimmering of the image was NOT due to beating with the video camera. It was a common feature of the TRS-80 and the System-80 due to 50Hz interference superimposing on the video sync signals, causing a slight time variance in the horizontal and vertical sync signals. The varying intensity is however caused by the beating with the camera frame rate. For the System-80, good shielding of the video signal helped a great deal. The monitor on the System-80 could be any TV that was modified (I modified a GAC B/W 12 inch portable - perfect TV for the job).
It is pronounced "ALPS" as in the mountain range, not A.L.P.S. Alps still make great key switches. They also made 3.5 inch diskette drives for IBM PCs. A Japanese company, they go all the way back to 1948.
Billy Gates wrote that BASIC interpreter I believe... one of the last pieces of hands-on hacking work he ever did. People forget Gates made a lot of money out of that Microsoft BASIC, well before the IBM made the PC.
I am sure the TRS-80 booted up with "TRS80>" as the prompt... must be a different ROM. Dick Smith's System-80 came up with "Ready>". The System 80 had 16K of RAM and if I recall upper and lower case characters up to 80 columns across. In some ways better than the TRASH 80, but the build quality was atrocious - absolutely terrible in comparison to the TRS-80. If someone has a System-80 they should give it to Dave to do comparative EMI measurements. The spectrum analyser would not only slow, it would have heart failure
.
Thanks Dave once again for the teardown and the excellent quality videos! Its like being there.
PS: One of Dave's CROs in the background was on the shelf upside down and another was right side up. Not sure what the go there is.