• Building an RS232 data cable for the PenPad

    James Fossey • 06/10/2023 at 20:55 • 0 comments

    I made a simple RS232 cable to connect my PenPad to a modern PC, via a cheapie RS232-to-USB converter off eBay.

    Amstrad helpfully supply a diagram of the PenPad's six-pin serial port (which thankfully uses standard RS232 - none of your fancy Psion 3 soap-on-a-rope cables here!) at the back of the instruction manual for the device. Even better - the pin spacing (pitch) is bog-standard 2.54mm or 1 inch if you haven't gone metric. If you don't have a copy of the instruction manual, the pin-out is as follows.

    Holding the PenPad normally with the screen facing you, LEFT to RIGHT the six pins are:

    1 5V DC (do not connect) -- 2 TX -- 3 RTS -- 4 RX -- 5 CTS --  6 GND [plus two cut-off pins]

    Using this information, it was easy to construct a cable using a nine-pin RS232 breakout board, five male-to-female jumper wires and a short length of female pin headers which mate nicely with the PenPad's serial pins.

    Next, I will cover some freely-available PenPad serial communication software, which you can still run today using a DOS emulator such as DOSBox or Dosemu2.

  • Cleaning the PenPad

    James Fossey • 05/23/2023 at 18:58 • 0 comments

    Anyone who has owned an unrestored Amstrad PenPad in the last ten years or so will be aware of The Goo Problem. Essentially, Amstrad applied a lovely soft-touch rubber coating to the PenPads when they were manufactured in 1993ish. Like all rubbery coatings, the PDA600's soft-touch sheen degrades over time, meaning that by the time Ashens reviewed one (hilariously) for his YouTube channel in 2012, the coating had degenerated into a horrible sticky goo. All PenPads will succumb to this eventually, unless they're on the Moon, but I've phoned NASA and apparently that's quite unlikely ;-)

    Luckily, the coating is fairly easy to remove - at least, to a degree that makes the PenPad vaguely touchable again. I used some isopropanol-rich hand sanitiser for this, and while my treated PenPad looks a bit 'distressed' as a result (see pictures) it's actually done a really good job of getting the gunk off.

    If you want to try and de-gloop your PenPad, I have a few tips:

    - start gently, using a minimal amount of sanitiser. This is especially important on the front casing if you don't want to rub off the logos.

    - remove the front casing altogether to reduce the risk of getting sanitiser into the electronics. You can do this by removing the screws on the back, opening the flap, and then *very* gently pull the flap upwards whilst holding the main body of the PenPad on the table. The cover should lift off easily - be warned that the digitiser might flop out of place as you do this, because the cover anchors it in place.

    - don't scrub the casing with a green kitchen scourer as this'll leave scratches (I learnt the hard way...)

    This method seems to leave the inner part of the flap with little 'pimples' on it - I'm assuming these are little bits of rubber that the sanitiser wasn't strong enough to remove. It's not a perfect fix; no such thing exists - sadly, you will never be able to make your PenPad look truly 'original' again.