🇺🇸 Hewlett Packard HP 95LX Palmtop PC: Part 2 (Repair & File Transfer) [#TCE0633]

I "Hallenised" the RS232 serial port ... modified it from 1x4 at 2mm pitch to 1x3 at 2.54mm pitch ... now I can create a serial cable and transfer files. I also re-wired the speaker so it'll work now. Hallenisation: making a modification to an otherwise perfectly functioning piece of equipment for reasons that are obvious to me but appear ridiculous to a normal person. I don't recommend changing the serial port pins ... a bit of a hassle. Getting transfers to work ... via null-modem cable ... was a little flaky at first but I got it working and transferred some HP 95LX specific software over. Needed to wire the 1x3-to-DE9 cable as a null-modem cable, not straight through serial. I'll need to get myself some additional PCMCIA-based storage ... up to 32MB I've read ... which will act as an A: drive. 00:15 ... Hallenising the serial port 09:20 ... Re-wiring the speaker 12:50 ... Reassembly 15:40 ... Does it still work? 16:30 ... Testing serial communication (send OK, receive NOK) 23:50 ... Working both ways! 25:10 ... Transferring PACMAN via XMODEM 29:30 ... Trying OTHELLO 31:30 ... Trying HP DUNGEON 36:35 ... Running diagnostics 37:43 ... Channel outro & thanks -------------------------------- From Part 1: Let's take a look at HP's first MS-DOS "palmtop" PC, the 95LX from 1991. This is quite a light little machine with 1MB of RAM, running MS-DOS (ROM) 3.22 on an NEC V20 CPU. It has a four-pin serial port, infrared and PCMCIA. It runs on two AA batteries and has a CR2032 for backup. It came with a US 10VAC power adaptor but seemed to be quite happy on 10VDC. It kept complaining that the battery was low despite fresh batteries ... hmmm. It has Lotus 1-2-3 built-in which seems to be quite usable on the "quarter-CGA" resolution ... 40x16 characters or 240x128 pixels. It also has a game called TigerFox (rev 3.3) by HP designed just for the machine. It does have a large piezo speaker but mine was disconnected ... the case has very obviously been opened before and they have perhaps cut the speaker wires, so I'll need to repair that. I don't have a plug that will suit the 2mm-pitch serial port pins so will replace them with 2.54mm pitch (next video) ... the two outside pins are essentially ground so only one is needed ... three 2.54mm-pitch pins will just fit. Overall it's a really neat little computer. I still want something that I can play "The Ancient Art of War" and PAC-GIRL on, so will look at getting a 200LX at some stage. -------------------------------- Check out my Patreon for regular blog-type updates between videos - there is a free membership tier and two paid tiers (US$2 and US$5). There is also a one-week trial for the paid tiers so if you don't think it's worth it, then cancel ... no hard feelings ... I appreciate any support, even if it's just subscribing to my YouTube channel!   / thecluelessengineer   -------------------------------- Music by Karl Casey @ White Bat Audio https://karlcasey.bandcamp.com    / @whitebataudio