Showing posts with label circuitboard. Show all posts
Showing posts with label circuitboard. Show all posts

Sunday, September 2, 2018

Taking Stock of the Final Expansion 3 Kit

I finally sat down yesterday and printed out the bill of materials for the Final Expansion 3 kit.  The assembly instructions can be found here.  https://www.lemon64.com/forum/viewtopic.php?p=767044

Note: This isn't a kit for the beginner, so if you are one you will have a better chance at success with help from someone with experience.  This is not a knock on the quality of the kit, which seems to be quite good.

So, I carefully examined each part on the bill of materials.  It was easy to identify most parts because they have markings that are listed.  There are three tiny parts without markings.  One is a crystal which is a tiny little metal can with two leads coming out of one end.  The other is a small white cardboard carrier with two tiny little rectangular dots.  These dots are two surface mount capacitors.

There are five surface mounted parts in this kit.  Assembling these is considered an advanced skill.  This will be my first time with surface mount components.  I am eager to give this a go.  YouTube videos showing how to do this are aplenty.

After carefully examining everything, I was able to account for all the parts in the kit.

Here is a photo of the unpopulated board.


I also posted a video about all this. 

Getting Ready to Build the Final Expansion 3 FE3 Kit for the VIC-20



Next stop - Assembly!  :-)

Thursday, March 18, 2010

Mousing Around

Since my Tandy 1000SX had high resolution graphics (if you could call monochrome CGA 640x200 high resolution) we thought it made sense to get a mouse and learn to program with it. Then we might be able to write even better software for the engineers to use when setting up each circuitboard for production. We had a crude graphical CNC simulator that ran on the Kaypro machines, so this could be a step forward for us with more detailed graphics and a mouse for a pointing device.

We bought the mouse at Radio Shack. It was a pretty nice little mouse, and it came with its own interface card like most mice did back then. I'm guessing that this mouse was made by the same people who made the the famous Microsoft Mouse. It was very similar. All the mice at that time had a ball for tracking movement, and this one was a metal ball with a rubber coating.

I believe that my first experiments with the mouse were in Turbo BASIC. There were no built in commands for the mouse. I don't remember exactly how the mouse was read either, but I remember there was documentation. Playing around with some code for drawing on the screen with the mouse inspired me to write an experimental character recognizer. I would draw letters on the screen and the program would attempt to convert them to ASCII characters. It really wasn't that hard to do, but prototypes don't have to be practical. It was fun.

The Epson QX-10

Somewhere we had acquired an Epson QX-10. This was a Z80 powered machine running CP/M, but it wasn't originally conceived as such. Epson had written a CP/M compatible operating system called TPM, and they had some lofty ideas about how a computer should interact with people. They chose Forth as the language to deliver their ideas. So there were some applications which were seamlessly integrated together, but this didn't wind up being a successful product.

So instead we treated this machine like it was another Kaypro. Bob asked me to write a program that would optimize the use of the fiberglass panels we made our circuitboards from. The panels were 24 by 36 inches (I think). For some order we might need a panel that was 8 by 10 inches. How should we cut the panel to reduce waste?

So I wrote a program in Microsoft BASIC for the QX-10. The user would enter the desired size of the material, and it would draw a rough image of the panel as it should be cut with instructions something like:

Insert the long way and cut 10 inches for 3 panels 10 by 24 inches.
Take each of those panels and cut 8 inches for 3 panels 8 by 10 inches each.
Total yield 9 panels 8 by 10.
Waste 1 panel 6 by 24 inches.

We used the computer for this purpose for several years. Hopefully the computer paid for itself in this role. :-)

Tuesday, February 16, 2010

Welcome to the Machine

Or welcome to the machines as it were. I think there were four Excellon drilling and routing machines at C.F.C. One of them had just a single head and was used for making first pieces to test for errors in the drilling and routing programs.

So my first job was to learn the programming language for these machines. Bob Spain and a young lady named Kristen Van der Laan were my teachers. This is no high level programming language, but more like a machine code of sorts. Circuitboards are still drilled and routed this way today more than 20 years later.

Here is an example of a very short Excellon drilling program. The actual language for CNC machining is based on commands used to control Gerber Scientific plotters:

M48
T1C0.028
T2C0.032
%
M48
G05
M60
T1
X2.550Y1.550
T2
X2.600Y1.650
X2.600Y1.750
M30

That drills just three holes of two different sizes. Writing programs to drill holes wasn't really the engineer's job. We mostly wrote programs to cut the boards out. Most of these were simple rectangles, and the program for this wasn't much longer than the example above. Sometimes boards would be circular, or have odd shapes. Some would have chamfers, fingers, slots, large inner cutouts. There was great variety. Sometimes we would make palletized panels which have more than one circuitboard. The routing was designed to leave only small perforated spots to hold it all together, and the boards would be removed from the panel either by hand or by machine.

We would write a program for routing using WordStar and then save it to a floppy disk. Then we would send the program out to the paper tape punch machine. The tape was usually gray, blue or pink. There were little tiny round pieces of colored paper all over the place.

A finished program would go out for a first piece to make sure it was correct. If you left just one digit out of a routing program the machine could destroy the panel, cutting straight through the middle of it.

Friday, February 12, 2010

A Fortunate Series of Events

In the spring of 1986 I discovered something that would change the direction of my life completely. I had been reading the Bible a lot in my teen years, but I didn't have a church community that fit what I understood from my studies until I found the Boston Church of Christ.

Late that year I decided to move in with some other young fellows from the church in Newton, but in order to do this I needed to find more regular paying work. I continued to work with Mr. Alessi but I began to look for a job. For some reason in the cold early spring of 1987 I worked for a few weeks at McDonalds and then suddenly I found an ad in the local paper. I remember the ad was titled "Programmer Trainee".

I went in for an interview. The company was called Circuitboard Fabrication Company, or C.F.C. It was hidden neatly in a neighborhood right next to a grade school in Newtonville. The president of C.F.C. was Bob Spain. He explained that this was a job programming CNC drilling and routing machines which are used to cut circuitboards out of fiberglass sheets. I told him that I was interested in developing computer programs and he responded that I may have an opportunity to do some of that at C.F.C. Small business owners like Bob Spain and Patrick Alessi are so openminded. :-) He offered me $5.50 an hour, and I accepted the job.

I began my new job taking the bus from Needham center to Newtonville because my car had broken down. Then after a few weeks I moved in with the guys from church. I only took with me what would fit in one carload. My new home just happened to be walking distance from C.F.C. It was very easy for me to see the hand of God in this arrangement.

I was surprised to learn soon after starting my new job that Mr. Alessi had used C.F.C.'s services to produce the circuitboards I had been assembling for two years. I had notice the marking CFC-1 on the boards and now I understood what it meant.

Monday, June 11, 2007

Floppy disks

In the early micro days we used cassette tapes and floppy disks. Floppies were better for many reasons but they were expensive. The Apple Disk II drives were $495 including the controller. Once you had one of these babies you still needed floppy disks. I remember pretty clearly in the early 80's spending $80 for a box of 10 floppy disks. These were Dysan disks, and were of very good quality.

However these disks probably exceeded the quality required. Later on some less expensive floppy disks became available from the likes of Maxell and memorably named Elephant Memory Systems. These were $2.50 or so per disk. The disk surfaces weren't as polished, and some cheap brands didn't have a reinforced mount but no matter really. The cheap disks were pretty much as reliable as far as anybody could tell.

Disk drive systems themselves were all quite different from each other. Apple's legendary Steve Wozniak had managed to create the ultimate in economy of design for a disk controller with a small card having only 5 ICs. Most other disk controllers were long circuitboards with 2 to 3 dozen chips. Monsters. ;-)

Some of these floppy drives used hard sector disks, meaning that there was an index hole in the media for each sector on the disk. So, if the disk was meant for a 16 sector drive, the disk would have 16 timing holes cut out of it evenly around the inner part of the disk. This would be read by an LED and a sensor. The Apple II used soft sector disks where there was only one hole cut in the disk, and the drive controller itself decided how many sectors to put on the disk by doing careful timing.

I remember that my father's H-89 had hard sector disks. The drives also made a strange clunking noise as they operated. The Apple II's drives made the much more familiar brrrr, brrr, mmm, mmm sound of most floppy drives and they were faster than the H-89 drives.