now here is the assembly instruction for the kit. All technical design details are described in my article (link at the root post of this thread):
I hope the pic is quite self explanatory (?) - Attention: As you can see, the GND-line of the FTDI-plug comes rightmost
Be careful not to accidentally bridge the pins of the 15pin connector - that could harm your pocket!
You need a fine tip for your soldering iron for this - and of course a flux pen is your friend
I recommend soldering all connector pins from the PCB's backside and then cutting and filing them flat.
PCB-cleaning after soldering with isopropanol.
You may want to cover the backside with some isolation tape after finishing.
The 10KOhm SMD-resistor (bottom of main PCB) is required at least for the PC-G8xx series (but not for the 15pin interface type pockets) - see article.
I designed an OPTIONAL DTR-LED for the PCB.
That means, if you equip the main-PCB with the LED + resistor, the LED lights up when the pocket sets DTR to HIGH.
This is the case, when it activates the RS-232 interface, e.g. by OPEN, LOAD or SAVE.
The green markings of the LED MUST BE ON THE LEFT SIDE (see pic).
Of course it's nice to have a direct visual feedback for that, but there's a drawback:
RS-232 capable SHARP pockets that are driven by coin cells (1350, 1360, 1475, ...) are quite stressed with driving an LED!
The visible symptom is a (potentially severe) fading of the LCD screen.
I would say the LED-resistor should not be below 820Ohm for those pockets.
On the other hand, with a 820Ohm DTR-LED-resistor at the PC-1600 the LED is just smoldering.
So, there is no single real good LED-resistor value for all pockets!
- If you want a versatile solution, just DO NOT EQUIP THE DTR-LED/RESISTOR!
- For AA- or AAA-battery driven pockets ONLY, use a 470Ohm LED-resistor.
- For coin cell driven pockets, use a 1kOhm (or larger) LED-resistor.
- As a compromise you can use a 820Ohm resistor.
The kit comes with the LED and 3 SMD-resistors for your choice (470Ohm, 820Ohm, 1kOhm).
Meanwhile, I personally decided not to use the DTR-LED, since I want an optimal one-fits-all solution,
and this feature is truly a nice-to-have, nothing more.
Since the original JAE-15pin plugs that SHARP used back then are out of production, we need a replacement solution.
I recently found these U-profile brass strips included with the kit - they do not provide a completely tight guidance, but are definetely better than nothing. Of course they are optional, and if you find something better - please tell us
For assembly I used superglue GEL, since that is adjustable for a while.
May be it's useful to glue a rectangular polysterol plate (or similar) on top of the 15pin assembly afterwards, for advanced stability.
Have fun building!
And as always, feedback and questions welcome