I'll have to track my copy down in the collection and get it read out (that may take a while, as I haven't seen the box I keep it in in a few years--horrendous filing system in my computer space). I made my soft copy of the manual from the old photocopy I had in my collection about five years ago--and worked on cleaning it up off and on since, as time allowed. It does work on both the /4 and the /4A.
Here's another really uncommon item, the manual for the TI BASIC Support Module, which appears to be the genesis of the BASIC Support Routines in both the MiniMemory and the E/A cartridges. The cartridge also had a RM option, so it had a bit more of the Minimem in it. . .
I took the scan I had and cleaned it up by typing the entire thing in (the original was too poor in quality to do an OCR scan of it). It includes the source code for the BSM, a debug version of the EA, the EA BASIC Support Routines, and the EA Save routine.
The file is much better size-wise too--535K instead of 6.1M
I have one of the cartridges as well. This manual just completes the set.
Finding a minor cut trace can be a real pain, especially when the board has been worked on several times. Ask @arcadeshopper about the weird traces I found on a disk controller board last year. There were a group of cut and shorted traces under the EPROM sockets. . .I cleaned them up and the board worked perfectly.
That was me with the original tip on the 25LS2521s, in the SAMS thread. The original tip goes to the folks at Unicorn Electronics though, as they were the ones who gave me the original tip. . .and they are a great source for older parts too.
The third slot would have been useful, but not strictly necessary, Fabrice. If someone really does need extra slots, they can always build a daughter board to plug into one of the existing slots that multiplies it to two or more additional slots, raised high enough above the motherboard that the daughter board can be independently supported. . .giving the user a TI(ny) Expansion Box.
If you like looking at source code, the source for several TI games is posted in the resources thread in the Development subforum. I obtained a copy of the source code for Parsec (printout) many years ago and eventually had a chance to run it through an OCR. The quality of the original was pretty bad, but between Paul Urbanus and I, we were able to clear up the errors, so the copy in the Dev thread is clean. Munchman source code is in the thread too, along with source code for several utility cartridges. I will soon be putting a clean copy of the source code for the extremely rare BASIC Support Module up there as well (I have about 30 pages of that one left to type in/verify).
Yeah, those trace widths worry me too. I try to stay with traces no narrower than .010 inches, with the same clearance between other traces and pads. it is usually safe to go down to .006 with most manufacturers, but I tend to use the larger clearances to avoid manufacturing issues.
The Myarc Mouse was a rebadged Z-Nix Turbo Mouse (bus mouse type, but it is easy enough to reconfigure the wiring of the serial mice to make them work as bus mice). I used to have a sheet I did up that showed the wiring changes needed, but I lost that in a flood years ago.