SB BBC @ GBR Oldie hints/tips #199-202 Hints and tips from the archives of Wakefield BBC Micro User Group... 199. Disc backups ~~~~~~~~~~~~ This is a sorry story but also a reminder. During the very hot weather, someone was working on a Master using the DFS and WORDWISE PLUS, they loaded a text file into Wordwise to amend and then to save the new version to a different disc. But unfortunately when they saved the file to the new disc it also saved the previous disc's catalogue information to the new disc including the other disc's start of file info, resulting in two files being split into FOUR. The person concerned unfortunately had not been keeping a backup copy of the discs but had luckily got printed copies of his files. So the moral is ALWAYS make backups regularly of your files or the unwanted will happen one day. Oh, by the way, the apparent reason for this unusual event on a Master was the heat. The Machine should normally operate at a temp. between 75 and 90 degrees F but was working at well over 100 degrees F! 200. !BOOT & MOSPLUS hint ~~~~~~~~~~~~~~~~~~~~ An interesting command provided by the MOS-PLUS ROM from Dabs Press, is *CONFIGURE START. If used in a !BOOT file, it can be used as part of a startup routine for loading one or more sideways ROM images, then doing a followed by loading a menu. It can be done on the Master 128 only, by *BUILDing the following !BOOT file.... 1 *CON. START CHAIN "MENU"|M 2 *SRLOAD ATSv31M 8000 4 Q 3 *FX200,2 4 CALL!-4 Note that you can of course use your own choice of ROM in line 2, (I have just used the new ATS ROM as an example), and your own filename in line 1. You should include in your menu program the command *CONFIGURE NOSTART in order to turn the command off when you exit from your menu program. (That's if you want to; otherwise every time you turn your machine on it will attempt to load your menu program.) 201. Configuring Escape key ~~~~~~~~~~~~~~~~~~~~~~ Have you ever wanted to disable , or totally clear the BASIC program in memory if Break is pressed? If you have, then the *FX200 command is what you want. There are four variations on the command: Command Action ------- ------ *FX200,0 Enable Escape, do not clear memory contents on Break (default setting) *FX200,1 Disable Escape *FX200,2 Clear memory on pressing Break *FX200,3 This combines the effects of *FX200,1 and *FX200,2 Don't forget to make sure your program works before you include these commands in it, otherwise you could lose valuable data, etc.. We hate to see grown men and women crying! 202. Beeb composite video output ~~~~~~~~~~~~~~~~~~~~~~~~~~~ The BBC Micro composite video output (BNC Socket) only gives out a monochrome signal. This is quite deliberate policy by Acorn, as the RGB output is best for high-resolution colour, and the absence of colour information on the composite signal ensures the best possible quality on a monochrome monitor. However, quite a few people do require a colour composite video output, and this can be achieved fairly easily. On early model Bs you need to solder a 470pF ceramic capacitor between the emitter of transistor Q9 (BC239) and the base of Q7 (BC309). These components are located a little to the left, and in front of, the ASTEC UHF modulator 'can'. This is a very cramped area of the circuit board, which makes soldering very tricky. On later Bs, there is provision for soldering this capacitor onto the board at the position marked C58; if you're lucky the capacitor may already be fitted. To complete the circuit, you then only need to link the solder pads marked S39. If you have a circuit diagram, such as the one provided with the Advanced User Guide, then look at the bottom right corner, just to the left of the UHF Modulator. The link S39 may be marked as LK39 on the diagram. On the BBC B+, all you have to do is 'make' link 26 on the main board. I imagine the link position will be somewhere fairly close to the UHF modulator can. On the Master 128, you can solder a 470pF ceramic capacitor between the emitter (right leg) of transistor Q12 and the base (centre leg) of Q13. These are located between the CV and RGB sockets, and although it is a slightly delicate soldering job, it is nowhere near as tricky as the equivalent modification on an early BBC B. Note: ~~~~~ Since producing this tip, I have been told that the circuit diagram, supplied with the Watford Master reference Manual, shows that you can apparently simply 'make' link LK11 on the PCB to get colour on the CV socket. Whether this is correct, and whether this has always been so right from the start of the production run of the Master, I cannot say. I don't even know where this link is, or whether any pins are fitted, or whether it's just a pair of solder pads on the PCB. However, it's certainly worth looking into before you start splashing solder all over the PCB! 73 Rick G4BLT @ GB7WRG