Synertek SYM-1 LED Display Replacement (1978 vintage single board computer like the KIM-1)
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- เผยแพร่เมื่อ 27 ส.ค. 2024
- This SYM-1 belonged to composer Richard Teitelbaum, and it came with some custom interface equipment he made for it, which my son and I check out here: • Composer Richard Teite...
Sorry I forgot to shut off the fume extractor during part of the recording.
Cool! I like these old computers from the mid to late 70's... I bought my first computer in 1981. A TRS-80 Color Computer w/ 4K of RAM.
Engineer lesson after a 30 year career: Value and appreciate your friendly lab techs!!!! Especially the ones who solder and re-work so neatly you cannot even see they've been there. And buy them lunch when they save your rear-end. :)
Truth. I hadn’t done a job this big in a while and it was a major pain.
Lifing pads ... been there, done that, still do it some times. As long as it is still fixable that is not a very big problem for me.
The problem with these old circuit boards is that they are not as good as the new ones. Applying to much heat for a longer time or putting mechanical stress on the pad or the plating of a hole would damage a board before even noticing. I've stripped some thru hole platings without even noticing anything went wrong so I became very careful when doing repairs on old boards. Hot air sometimes works but since the pads on old boards tend to be bigger, there is more solder and it takes a longer time to completely heat the pad, thru plated hole and the pad on the other side there is a higher risk on damaging (even de-laminating) the board
Yeah -- I had never tried to desolder anything on a board this old before. It was... not fun.
Oh dear. Look at the manual on line.
Yup, we've entered the add-two-numbers test program and got that running. Next up is to hook up the cassette interface and the serial terminal interface.
We were also able to read the ROM that has a custom program written by the previous owner and ran it through a disassembler; I've tasked a student with trying to figure out what it does.
1:37, you (or how i write this) should have added more fresh solder to remove the solder to prevent lifting pads.
More to evenly heat all pins and lift the 'display' on the other side bit by bit with a flat screwdriver or needle a than clean up with wick.
I do the adding-solder trick already. I haven't done the hot air trick with through-hole; I'd also thought of that as a surface mount thing, but it's a good idea.
one should have a PCB holder, a device to enables you to hold the pcb and rotate, it's hot. it happened to me as wel few times while wanting to change resistors, now i use special footprint if I'm not sure witch resistor value.@@Lantertronics
Terrible work.
Why are you not using sockets?
The original didn’t and I wanted to maintain the same look.
There is nothing wrong with the board.
Yup, it's working great (as far as we can tell) after replacing the LEDs.