Commodore 128D and CP/M

I shall be away for the beginning of this year’s Retrochallenge, so in order to hit the ground running when I get back I thought I’d make sure all my machines were primed and ready for action.  To that end I’ve recently sorted out the batteries in my PX-8’s and today my attention turned to my Commodore 128D.

The machine is in pretty good condition, the cassette port is a bit flaky and the built in 1571 drive seems to read and write to disks reasonably successfully.  My interest lies in using CP/M on the C128 and I really needed to secure a way of getting data into the machine in this mode.

This has caused me some considerable headaches, in its native or C64 mode the machine uses Group Character Recognition (GCR) to write data to the disks in the 1571.  The 1571 is also capable of writing Modified Frequency Modulation (MFM) disks as used by CP/M and under CP/M disks using the following formats can be read:-

With third party software such as Juggler even more formats are supported.

Armed with Big Blue Reader, the original CP/M system disk, a clutch of DSDD disks and my bridge machine running DOS and 22Disk I thought I was well prepared.  However no matter which combination of disks and formats I use I cannot successfully format a disk with the 1571 nor the 1581.  I’m pretty sure the disks are OK, they seem to work without problems with the Epson TF-20 and PX-8 and the 1581 and 1571 drives appear happy to do everything except format.

More in desperation than hope of success I put one of the disks that I’d formatted with the TF-20 and PX-8 in the C128, typed DIR.  To my surprise and excitement the C128 came up with some text at the bottom of the screen reading Epson QX-10.  I pressed return and the drive chugged away, thought about it for a while and came back with ‘No file.’ uh, there were definitely files on the disk.

I had a search around and discovered that when the format description comes up at the bottom of the screen you can cycle through different options.  So I tried again and using the right arrow key found the next selection was ‘Epson Euro’ I pressed return, the drive chugged away and up popped the disk contents, yipeee!

I loaded PIP quickly just to check it worked, which it did and I then formatted a fresh disk in the TF-20, copied the text adventure Snowball onto it and put it into the C128.  On the first attempt I got a BDOS error but on the second attempt it loaded.

So I now have a way of getting software downloaded from the Internet into the C128 in CP/M mode, albeit a somewhat circuitous route via the PX-8 but a way nonetheless.

I currently have the C128 hooked up to an IIyama LCD panel via the s-video port which means I can only run in 40 column mode however I do have a cable that will allow me to connect via Scart and run in 80 column mode which I shall try next as much of the software I’ve tried assumes this mode.

So now hopefully I’ll be able to get on with things as soon as I return, try some CP/M software on the C128, hopefully get it talking to the Epson PX-8 via RS232 and I have some unused 3.5″ DSDD disks on the way which I’m hoping I’ll be able to format successfully with the 1581.

PX8’s, Batteries & Retrochallenge 2011

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.

More Amiga Adventures

I’ve been spending a fair amount of time messing around with the Amiga 1200 that I recovered from the loft a few weeks ago.  It has been a little frustrating, I’d forgotten a lot about the Amiga and its idiosyncrasies and progress has been slow for several reasons that I’ll get in to below.

One of the main challenges I’ve found with retrocomputing is transferring files to and from your retro systems.  With the Amiga 1200 this isn’t really an issue due to its PCMCIA slot which will happily read and write to standard compact flash cards with the appropriate adapter.  A PCMCIA to CF adapter was therefore my first purchase (I later discovered I already had one grrrr.)

My next purchases were an IDE to CF adapter and some Kickstart 3.1 roms.  Installing the latter was pretty easy although it’s important to note the manner in which the original chips are installed as there are more sockets than there are pins on the chips.

I then pulled out the original Seagate IDE hard disk, plugged in the IDE to CF adapter and added a SanDisk Extreme III 4GB CF card.  I booted the system with my Workbench 3.1 floppy and set up the newly installed CF card.

I divided the card into a 200MB partition for Workbench and the rest as one large partition for games and data.  After formatting the partitions (some considerable time) I made a fresh install of Workbench 3.1 and booted the system from the new CF drive. This whole process was a little tortuous as the Amiga kept crashing at various stages.  At first I assumed the CF card was incompatible but I soon realised the 128MB SIM I’d installed was causing the problems.  I swapped it out for a 4MB stick and the machine become much more stable.

The next challenge was installing AmigaOS 3.9 which is supplied on CD and at the time I didn’t have a compatible drive for the Amiga.  Using a Mac I copied the contents of the CD onto a compact flash card in a drawer name AmigaOS3.9 and inserted it into the Amiga.  I then fired up shell and entered the following command – ASSIGN AmigaOS3.9: cf0:AmigaOS3.9 and was then able to run the installer with the CF card mimicking the CD.  However I ran into a number of problems with the installation and have since learnt that using a non-Amiga system to copy files or open archives destined for the Amiga can mess up the file permissions when you then try to use those files.  After much fiddling I finally got a semi working installation of Amiga OS3.9.

I seem to have stopped using my Amiga just at the point that CD rom drives became quite widely used with the system, I personally never had one but wanted to add one now so I could install the OS properly.  I ordered a buffered IDE interface and dug out an old Plextor external USB drive.

I opened up the back of the drive and disconnected the USB interface from the IDE connector on the drive and ran an IDE cable out of the box and into the Amiga.  I had to make some changes to the Tooltypes of the CD driver that had been installed by OS3.9 to get it working:-



I now had a working CD ROM drive and was able to successfully install OS3.9 without problems and also install the Boing Bag 2 update.  My next ambitions are to replace the external drive with an internal one, I already have a slim drive from an old Cubit box, whether I have the courage to cut a slot out of my 1200’s case is another matter, and Internet access.  For now some Frontier Elite II.