This is an enclosure for Jean-Francois (Jeff) Garnier PILBox PCB. See his page at http://www.jeffcalc.hp41.eu/hpil

I have had a non-functioning HP 812164A (HP-IL to RS232C interface) in my stash for years. Try as I might, I could not revive it, it's dead as a door knob, so I desoldered its HP-IL connector block and thought I could reuse it on my PILBox.

If you don't have one of those connectors, I also made a front panel with two holes to pass HP-IL cables like the original PILBox (although I don't condone cutting a perfectly good and super-rare HP-IL cable in two).

There are two holes meant for 3 mm LEDs. One LED is connected through an inline 330 ohms resistor to pins 1 (ground) and 2 of JP1 (near the USB module) to indicate power, and the other is connected to the LED1 pads on the PCB (mind the polarity: cathode - negative - is the pad closest to the PIC). The two LEDs are held in place in the front panel block with a lock.

As you may notice on the photos, I used “Dupont” connectors as I was experimenting, but you can solder the leads directly on the PCB. Allow a good three inches for the power LED.

On the photos, you will see I replaced the block terminals with JST XHP-3 connectors after removing the central pin. These connectors help maintain the correct polarity of the connectors (still not certain it's important, but I did not want risk it). One of the issues, and the reason I could not solder the connector block directly on the PCB, as it was in the 812164A, is that Jeff chose to place the input connector on the left, the opposite of what you find on the HP made connector block. I could have flipped the PCB, but then the USB connector would have been upside down. So, ADHD, OCD, and all that…

The connector block is held in place by the original screws from the 812164A, the enclosure itself is secured with four M2x8 Phillips head self-tapping screws.

Here is the result. It's longer than the original enclosure Jeff is issuing with his kits, because of the connectors and the little extra room that was needed for cable management, but I think it looks neater (despite the noticeable elephant foot I am getting with that terrible filament I bought).

Now to find that HP smokey dark brown filament to match the rest of the HP-IL peripherals…

20231029 Update: I did find a filament that exactly matches the colour of HP peripherals! Polymaker dark gray green PLA