Avoid dashing away with a soldering iron - David Janda tests a BBC sideways ROM board

Romex 13 is a BBC sideways ROM board which allows use of a maximum 16 ROMs/EPROMs, keeping instant access to software.

The board can be (mostly) plugged into the BBC, (avoiding the need for a soldering iron). It also sticks to the underside of the micro's lid, leaving room for more boards.

This flow-soldered board is buffered and has 13 28-pin sockets. It is compact, measuring 19 by 9.5cm, and unlike other boards it can be stuck to the roof of the micro by four sticky printed circuit board spacers. The Romex board can be removed by pressing in tiny latches on the spacers, allowing easy access to the fitted board.

Three leads connect the board to the BBC; there's a 28-pin and a 16-pin plug cable, and a two-way ribbon cable which slips on the lower of the two links of S21 on the BBC.

ROM-based software, such as the word-processing chip, View, can be plugged into any of the spare sockets on the Romex board, or the main BBC board.

Four different types of EPROM software can be used. The most popular, 27128 (16K) and the 2764 (8K), plug into any socket on the Romex board. The 4K and 2K EPROMs, (2732 and 2716) can also be used on making changes to links on the board. There is, however, only one socket on the Romex board which can be used for the 2K EPROM; apparently the issue two version to be available late in January incorporates the facility to use more than one 2K EPROM.

Installing the board was made easier by the excellent documentation as both text and diagrams are clear and easy to follow.

Remove the micro's lid and turn the keyboard on its front. Remove IC76 from its socket and insert one end of the 16 pin dual-in-line plug.

If your BBC doesn't have IC76 in a holder, GCC send you a four-way cable and instructions free. The four-way cable replaces the 16-bit Dil plug, and must be soldered to pins 11 to 14 of IC76. To do this, remove the IC next to IC76 from its holder, as this will give you more room; also use a fine-tipped soldering iron. Although the task of soldering the cable to IC76 was fiddly, the cable was helpfully colour coded with the individual wires a decent distance apart.

Next, plug the 28 way Dil plug into one of the BBC's spare sideways ROM sockets. Remove the tape from the spacers on the Romex board and stick the board to the inside of the micro's lid. Release the latches to remove the board and stick on a fifth space to support the middle of the board.

If IC76 is in a socket, it can be plugged into a reserved socket on the Romex board, and the 16 and 28 way cables plugged into their own sockets.

However, this proves easier said that done, because you need to get someone to hold the lid while you fiddle with all the cables.

Now you can install your ROMs/EPROMs. IC14 on the Romex board takes priority so it's best to install a frequently-used ROM here. The socket with the lowest priority on the board is IC3 and after that it's IC's 101, 100, 88 and 52 on the BBC. The 28-way Dil plug uses up one of the BBC sockets and there's a socket on the Romex board which will incorporate the ROM that would have been in its place.

The Romex 13 is good value for money, and well designed. Sticking the board to the lid of the Beeb allows greater air circulation and doesn't clutter up the main Printed Circuit Board. The board doesn't allow the use of CMOS RAM chips, but for those who use prepared software, the Romex 13 is the best I have seen.