While trying to explain the meaning of the carry digit during addition an subtraction to my oldest son, I’ve given him a nice little device to play with: the Addifix-9 number cruncher.
I’ve briefly mentioned this device before in a post. This time I’ve made a short video about the mechanical calculator in action and present more details:
In the 1950s/60s The Addifix series was sold as “Addifix-9 Taschenrechenmaschine” by the German mail-order company Neckermann. Its predecessor was the Addiator from Carl Kübler which was sold since the early 1920s [Source: sliderulemuseum.com]. The underlying mechanical principle is quite old (an documented example is the mechanical calculator by Claude Perrault from the 17th century).
The Addifix is a pocket-sized (13 x 9 cm) slide adder that can be used from both sides – one side for addition and one for subtraction. The slides (one for each digit) are handled with a metal stylus.
Ah! Those memories… I just found an old Amiga floppy disk while cleaning up: Dr. Fruit
Dr. Fruit aka Doctor Fruit (Hall of Light reference) was an arcade game from 1987 that had a lot of gameplay similarities to Digger and Boulder Dash.
I remember playing it a lot when I was a kid. Nice mazes, but inaccurate joystick control and one of the most annoying music loops I’ve encountered in my life.
Needing a replacement for the long ago discontinued Sharp-PC connector JAE PICL-60P-LT, I dug through a lot of datasheets and finally found a pin-compatible one:
Hirose HIF6A-60PA-1.27DS – Datasheet
Hirose HIF6A-60PA-1.27DS – Digi-Key Link
The connector fits good enough for my purposes. If necessary removing a bit of the plastic case left and right of the pins improves the connectivity as the replacement connector is a bit broader.
There is also a version with mounting holes (HIF6B-60PA-1.27DSL) which I will also try to get my hands on (currently not in stock).
My original solution was to use a 2×30 1.27×2.54 pin header as shown in this post, but the narrow space between the pins led to serious constraints in designing a new interface board (more about that when it’s ready).
I wanted to make a small tutorial on how to reverse engineer old PCBs, in this case how to trace the vias of a Sharp CE-160 cartridge.
After disassembling I’ve made photos of both sides of the cartridge:
The following step was inspired by an EEVBlog tutorial on reverse engineering a Rigol DS1054Z. The two photos were then aligned (photoshopped) to fit onto each other when printed. One of the two layers needed to be mirrored, and it took a bit to align all vias. Luckily the two photos was taken with a tripod from the same angle. The result was printed onto plastic photocopy foil.
This allows tracing the routes from both sides, including the vias.
In some cases traces were hidden under chips or other parts. I used my multimeter (set to measuring resistance) and needle pin tips to trace them:
Two months ago I was contacted by Tom who asked me for one of my Cartridge Breakout Boards. He wanted to build a 256k memory module for his Sharp PC-1600. Well, I was happy to provide him one of the boards for free and two weeks ago he informed me that he succeeded in building an expansion module:
He kindly offered me one of his modules. 🙂 I still have to take advantage of the ‘enormous’ amount of memory my Sharp PC-1600 now has. So far I’ve done a bit of testing and the results are pretty impressing:
Thanks again, Tom, for sharing this with me.
Update: For my French friends out there – there is actually a thread (Extensions mémoire 256KB…heu non… 512KB) with more details on the cartridge mentioned above.
The following cartridge adapter board completes my already presented series of Sharp PC adapters: my Interface and my Cartridge.
The Sharp PC-1500 and PC-1600 can both be extended via one (two) module slots. Pretty common are memory extension cartridges, but there are also more sophisticated modules. I have a few that contain an (E)EPROM with program code on it. I have a few of the latter ones and to facilitate reading out their content I’ve built an adapter board:
The 40-pin connector was cut out of a regular PCI slot (not PCI Express). You can actually get two connectors out of one slot.
Pin headers allow easy access to the data, address, and control lanes of the cartridge. In many cases this allows easier debug access to the content of a cartridge (it EPROM) than reading (i.e. ‘beeping’ out) its content directly via the PC-1500/PC-1600 + PC-150 interface.
The adapter board works for me but it can be pretty annoying to get the pads of a module aligned with the connector pins in the 40-pin slot. It usually takes me a few retries to get good contact on all pins. Some kind of guide rail on both sides would be helpful, but hey, it’s a hack… 😉
Just wanted to say “Thank you” to Eric from www.pc-1500.info for supporting my efforts to create a new USB interface by sending me a TRS-80 PC-2. As a gift!
Not only that, he also sent me a CE-158 serial interface manual (here shown below my interface). Really thanks a lot! 🙂 And Merry Christmas!
For debugging purposes (and also for playing around with memory chips on a bread board) I’ve created little breakout boards for the cartridge slot on the bottom of Sharp PC-1500s/1600s.
I’ve added a layer of foam (not visible on the photo) on the bottom side of the cartridge to prevent the pin ends from scratching on the case.
Typing on the PC while having cables connected to the cartridge is a bit annoying as I tend to pull off the cables when turning the PC around. I’m currently figuring out a better solution by using ribbon cables instead of the pins. I will update the post as soon I’ve managed to make photos of the modified version.
Just a little update for all readers interested in Sharp 1500/1600 PCs: for hacking around with the Sharp Pocket Computers I’m using a self-made breakout board that allows easy access to all 60 pins of the interface connector.
The 60-pin connector is a simple 1.27*2.54 60-pin male header (I’ve bought mine here).
Two LEDs indicate battery or power connection, and on/off state. (In most cases power lights up as soon as the board is attached to a Sharp PC.)
It’s not that easy as it may sound to find paper rolls for a 30 years old printer, the Sharp CE-150. The printer is used in combination with a Sharp PC-1500/1500A pocket computer.
I’ve looked at my small amount of paper rolls, the leftovers I’ve found in a box on the attic. Interestingly they were differing in size (can’t remember why):
|(Left to Right)
Their width and outer diameters did not differ significantly, but the core diameters did. Paper rolls with core diameters of 7-9 mm are hard to get, the rolls sold today mostly have a diameter of 12 mm. I’ve successfully tested thermal (yes: thermal) paper rolls with this diameter in the CE-150, and these are really cheap to get (e.g. on eBay Germany). The ink doesn’t run, but there might be paper rolls with different coatings. I did not check that.
Maybe as a warning: Thermal papers mostly contain Bisphenol A (BPA), a substance that exhibits hormone-like properties!
The approximate dimensions you should look for are:
Width: 57 mm; Inner / outer diameter: 12 / 30 mm; Length: 10 m