Category Epson PX-8

PX8’s, Batteries & Retrochallenge 2011

Retrocosm 6 Comments

Lately I’ve been experimenting with new batteries for my Epson PX-8’s (I have three PX-8’s now, it’s a worry I know.)  Of the three’s original batteries, one still holds a reasonable charge, the other two however require the AC adapters to be permanently connected.  This is not a huge issue but with high capacity NiMh batteries pretty cheap these days I decided to look into replacing the original NiCad’s.

The original NiCad’s are 4.8 V 1100 mAh packs, ideally I wanted replacements that were of equal or greater capacity.  Having hunted around and looked at a myriad of options it became clear the most limiting factor was the size of the battery compartment on the PX-8.  Initially I was tempted by a 4 pack of 1.2 V AA cells at 2700 mAh, however there was no way of squeezing these into the compartment even with a homemade pack.  I also looked at new NiCad’s but really wanted to go with NiMh.

In the end I tried two options, a ready made four pack of Sanyo Eneloop AAA cells at 800 mAh and some loose Duracell AAA’s at 1200 mAh secured in a simple 4 cell battery holder.  Both options are working well and lasting for what seems like forever.

I’m no expert on battery charging so don’t fully understand what the consequences will be of using the supplied Epson adapter and the PX-8’s charging circuit on the modern NiMh’s.  From what I do understand the PX-8 will charge for 8 hours and then drop into trickle charge with its standard NiCad.  If you disconnect the AC adapter and plug it in again the charge cycle will start again possibly leading to overcharging.  The AC adapter is an unregulated 6 V 600 mAh model. (Epson HOOAAU-A)

As far as I can tell, the NiMh’s are taking somewhere in the region of 2 hours to fully charge which seems to me to be what’s considered fast charging.

With July rapidly approaching my thoughts are turning this year’s Retrochallenge.  I have a number of possible avenues to explore.  Continuing with the battery theme I really would like to try and revive my PF-10’s.  I’m pretty sure the problem lies with dead sub batteries inside the units.  The main batteries are easy to swap out, however the sub batteries are soldered to the logic boards and it’s been a long time since I’ve been near a soldering iron.

I also have a Commodore 128D which I’d like to get fully acquainted with including using it with CP/M, in fact it would be nice to try and get it talking to a PX-8.  On that theme I’ve been experimenting with the PX-8 RS232 ports and quite fancy writing some sort of two player game with communication via this route.  Decisions to be made.

Retrochallenge Winter Warmup 2011 Entry

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Well here it is, the first installment of Silent Running, a text adventure created using Inform.  The initial idea was to create something that would run on my Epson PX-8 which is a CP/M based machine. The first speed bump was locating a Z-machine interpreter for CP/M until it was pointed out to me that as I had the original Zork games for CP/M I had a suitable interpreter.

The Zork games typically came as two files, for instance, Zork1.com and Zork1.dat, the .com file being the interpreter and the .dat file the story file.  The interpreter supports version 3 story files and if you create a compatible story file you can rename it Zork1.dat then run Zork1.com and your game will load and run.

Needing to create version 3 story files I opted for Inform 5 as the compiler and was of course free to write the source code in any suitable text editor.  Thus development has taken place on a variety of machines including the Atari Portfolio, Epson PX-8, Epson Equity LT and some more modern machines.  I had hoped to compile the code on the Equity but I still haven’t had any success.

The game itself is heavily influenced in tone by Snowball from Level 9 which remains my fondest memory of text adventuring, that and Melbourne House’s The Hobbit.  I would estimate that I’ve completed about a quarter of what I’d hoped, therefore there are a number of elements within the game that may currently seem like red herrings.  The current goal is to achieve access to the biodome area of the freighter.

There will of course be many bugs, not the crash your system type, but responses to player input that are not catered for and the like.  Once you’re in the world creating it it’s difficult to jump outside and imagine how others are going to interact with it, reports would be welcome.

I’ve been quite absorbed by this process which has been enjoyable although it has meant I haven’t had as much time to keep up with all the other entries as I’d have liked and I’m looking forward to doing that now.

You’ll need an interpreter should you wish to try the game, you should be able to find one here:-

Link to Interpreters

Download Silent Running Story File

If like me you need an interpreter for CP/M you can download Zork and the included interpreter here.

Retrochallenge Update

Retrocosm 2 Comments

I’ve made a fair bit of progress today, tidied up a fair amount of code, resolved a number of issues that were returning slightly odd results when the player did unexpected things.  I came across some documentation that alluded to setting parameters for the target displays  Sad I know but this was quite exciting given the limitations of the PX-8’s display and the fact that the only CP/M interpreter I have doesn’t as far as I know allow you to specify display settings.

I therefore compiled a version for the PX-8’s 80 column by 8 line display and while I was as it one for the PX-4’s 40 by 8 display.  I transferred them over and… it didn’t work.  At the moment I don’t know why it’s not working and I also don’t know why I took some video of it not working but I did.