As most 2068 owners know by now, you can gain access to the hundreds of Sinclair Spectrum software titles available in the U.K., by changing your 2068 ROM (Read Only Memory). This can be done in a number of ways, and one quite elegant method is by the use of the Russell Electronics‘ Romswitch.
Romswitch is a small (2″x2″) double sided PC board on which is mounted a Spectrum 16K ROM chip; a glass encapsulated, miniature magnetic reed switch; a pair of pullup resistors and a socket for your Timex Home ROM. The board layout is straight forward, and despite the use of one jumper, the plated through holes indicate a desire for high quality design and construction. The final component of Romswitch is a small “button” magnet mounted on an adhesive backed slide. We’ll talk about that later.
Installation of this device requires only a Phillips and a regular screwdriver. It involves opening your 2068 case to install the board in the 16K ROM socket. The procedure is simple and described in detail in the accompanying documentation. Having installed several Spectrum ROM’s myself, I think I can say that the documentation is quite complete, and it should allow anyone with a reasonable amount of manual dexterity to perform the installation. After closing the case, you install the button magnet “switch” on the keyboard (next to the 0/DELETE key). You must move the switch around to establish the proper placement (before removing the adhesive backing), but since you can hear the reed switch (experiment with this outside the machine before you start) contacts closing, this task should pose no serious problem.
Once the “switch” is installed, you can go back and forth between Spectrum and TS2068 at will! (POWER OFF ONLY!!) While I strongly recommend that you do not flip the switch with the power on, I tried it anyway. No harm was done (guaranteed crash and loss of program), but you might initiate bus contention during contact, and that could lead to loosing a chip. Anyway, this is the singularly outstanding feature of Romswtch over the other conversion methods.
Two other methods of Spectrum conversion are Doug Dewey‘s (TSUG, 206 James St., Carrboro, NC 27510) Chameleon (EMU-1), and of course, simple ROM replacement. With the Chameleon, you must insert and remove the cartridge board each time, although it requires no tools to install and leaves your warrantee valid. Direct ROM replacement needs tools, like Romswitch, and requires opening the case for each change, but the cost is less than $20.00. Both Romswitch and Chameleon will each draw more power as both chips together will draw more juice. Meanwhile, Romswitch will give you a way to switch back and forth, without opening and closing anything, without drilling a hole in your case for a switch and will leave your cartridge and edge connectors open for other applications.
The one weakness of the Romswitch is that same magnetic switch. Mine started to move around after a while, so be sure to clean the keyboard area well before application of the switch. Unfortunately, the Spectrum Rom is soldered in with pin 27 cut off. This makes the board or the chip difficult to reuse for other purposes.
Overall, I give the Romswitch a 9 out of 10. Quality and convenience are high, but so is the price. I would like to see a kit or bare board version made available for development projects. Romswitch is a viable contender in the field of “Spectrumizing” your 2068, and it may be just what you’re looking for.
Available from:
G. Russell Electronics
RD1 Box 539
Centre Hall, PA 16828
$55.00