I did say yesterday that I’d post more once I’d stopped swearing. Truth of the matter is that I haven’t stopped swearing in the slightest.
There’s a BBC Master 128 in my collection: it’s almost 20 years old to give it its due, and the CMOS battery pack inside had badly corroded so I replaced it. I’ve also made an attempt to repair one of the shift keys – the internals of the keyboard switches are prone to oxidisation but the entire damn lot of spares I had were oxidised too. How tedious.
Anyway, as mentioned yesterday I’d picked up an internal 65C02 second processor, which upgrades the 128 to the Turbo model and enables it to run the Level 3 Econet fileserver software. I also picked up the 8-bit IDE module from JGH and set it all up. That’s where the troubles began. You see, things like the IDE module and the GoMMC rely on patched filesystems and external utilities for things like formatting, firmware upgrades, etc. which is all well and good, but a pain in the arse if you’ve only got 5.25″ drives attached to the Beeb and the only floppy drive in the house which will work on a PC is a 3.5″ one.
So, thinks I, I shall be clever. I pulled the RiscPC out from its resting place and connected it up to the sole SVGA LCD sitting in the house. Nothing. Nada. Not an electronic sausage. The RiscPC is just too old, and the LCD panel is just too limited in its range – fine for a Windows box, crap for something which requires some sort of odd sync. I swear for a short space of time, and then remember I used to do transfers like this using serial leads.
Problem #2 occurs – the BBC’s serial port requires a 5-pin domino DIN connector, which aren’t made any more. After fighting with a pair of pliers, I manage to construct a 5-pin domino connector and Google for a suitable pinout, selecting the first likely candidate. Soldering iron gets fired up, and I start building the cable (bear in mind it’s easily 5 years since I soldered anything, probably 10). At this point, there’s a huge crack sound from the garage. I investigate, and smoke is coming out of the Master 128’s switched-mode PSU. I turn it off, and then back on to be greeted with the familiar ‘beep boop’ – doesn’t seem too bad, so I leave it switched off while I go back to finishing the cable, which takes me about another 20 minutes.
Return to the workbench, start up one of the BBC B machines with ADFS in. Find the old Comstar-II ROM. Connect the serial lead. Try to talk to it. Nothing. I return to the laptop and Google some more to find out the relevant *FX command to change baudrates. In that time, I discover Angus Duggan’s serial cable pinout with a completely different set of pinouts. I swear once more, fire up the soldering iron, desolder my connector and resolder it with the correct pinouts. It works! Hurrah! Much celebration!
The celebration however is shortlived as I discover that Comstar’s XMODEM file transfer routines are shonky enough to barf at things over 200kbytes in size, and can’t do flow control properly so there’s retries every time it saves to floppy. So off I go to dig in the floppy disks eventually returning half an hour later with a copy of Gareth Babb’s term application, which does the job and at 19200bps as well. I now have, er, a 5.25″ floppy with all the software on I need. Time to plug in the IDE drive to the Master 128, and get it going. I duly do this, and find that I can no longer access the floppy disk. Bollocks. So it’s either the floppy or the hard disk. Further investigation reveals that the 1MHz bus doesn’t actually think it’s got anything plugged into it. There’s a tale involving the GoMMC as well, but that’s pretty much got the same level of success.
I’m starting to think that:
- The BBC Master 128 is so knackered that the 1MHz bus is blown, and it’s doing odd things internally.
- The MMC card I have for the GoMMC isn’t compatible “enough”.
So, I’m on the lookout for another Master 128 (got one in the loft? Give me a yell please!), and Kieran’s bringing round an MMC card he has kicking around the place.
I just keep thinking of the satisfaction I’ll have when it’s all working, and my mind inevitably wanders to the thought that I haven’t yet worked out a reason why I’m doing this.