









Resources
Wiki
oldcomputer.info
ganjatron.net
Yet Another Computer Museum – some ROM images inside
Basic Programs
bahamas.gestalter.at – programs
Documents
Internals
Motherboard





SW6 microswitch is used to set the language version – please see page 29 of the user manual (document available in the documents section above). DIP switch 4 of that switch must be set to OFF or it will be impossible to enter BASIC.
Memory Expansion



Battery

The original battery seems to be NiCd 4×1.2V 480mAh. Please see the Tips and Tricks document on the battery replacement recommendation. It is possible to run the machine without any battery, but not with the original power supply, which would provide to high voltage. A regulated external power supply worked well and the voltage range of 5-7V was right to power the computer, however with lower voltage levels it will have troubles operating the printer and tape recorder.
Keyboard




Display





The LCD display module of Epson HX-20 is right above the battery compartment and leaking battery damaged the traces on the board and the connecting tape. There was enough length of the tape to solder the wires to the board – these wires come from an IDE HDD tape. It is possible to solder the wires directly to the tape – the tape will not melt with soldering temperatures up to 350 centigrades.




Tape Recorder













Printer






The non-thermal printing paper ribbons are broadly available today. The ink cartridge is still manufactured by Epson, its symbol is ERC-09.


Reassembly













That’s a pretty good repair on that flat ribbon cable, tried that myself once but wasn’t that successful. Since found you can buy those flat cables in all lengths and sizes quite cheaply from a few ebay sellers.
Does anyone have the manual or commands for using the EpsonLink communications ROM for the HX-20?
I don’t know what Epson Link provides in reality, all I can read is it enables serial communication. There is a description of serial communication protocol in chapter 4 of software manual. But perhaps Rom offers higher level file access etc?