The Chroma 81 interface is available to purchase directly from me at the following price:
- Chroma interface = £60.00
- Postage and packaging (Signed For delivery):
- Within UK = £4.95
- Within Europe (airmail) = £9.75
- Outside Europe (airmail) = £11.15
Please email me for full payment details, postage costs for multiple items and to check current availability.
- The interface only outputs a picture in RGB format (not composite video or S-video).
- The interface works with both 50Hz (UK and Europe) and 60Hz (USA) models of the ZX81.
- The interface has not been tested with any clones of the ZX81 and must therefore be assumed to be incompatible with them.
- It is strongly recommended to use the 1.2A version of the ZX81 power supply. The original 0.7A version might not be sufficient if other devices or a ROM cartridge are to be used. If more current is drawn than the power supply can safely handle then it could overheat and pose a fire risk.
- The SCART output accurately reflects the picture available from the RF output. Slight shimmering or bending of the top row of the picture will be visible if it occurs in the original RF output.
- Flat screen TVs made by Panasonic do not appear to implement the SCART specification correctly and can result in the Chroma picture being shifted to the left or at worst being unstable and continually jumping horizontally. There may be other TV models that also do not display the picture from the Chroma interface correctly, but most makes appear to work ok.
- The interface is fully compatible with the ZXpand SD card interface.
- Flicker-free games originally developed for use with the ZX80 fitted with the 8K ROM upgrade may not display a perfectly stable picture due to inaccurate timings in the games. A TV tends to be far less tolerant of frame timing variations in a SCART signal than it is in an RF signal.
- A SCART cable is not included. Almost all commercially available RGB SCART cable will be suitable, allowing you to select your preferred length.
- A RS232 cable is not included. If your PC does not have a built-in serial port then a USB-RS232 adapter can be used. A standard 9-way non-crossover serial cable is suitable for use with the RS232 socket, and can be used to connect to a serial printer or a PC (although note that custom software must be created to control the RS232 port).
- The Chroma interface is uncased (I hope to be able to offer a custom case in the future if economically viable).
- The main logic IC and onboard 5V converter can get hot in use but this is expected behaviour.
- Modern TVs tend to struggle to display the RF output from a ZX81. However, it is usually possible to obtain enough of a picture to prove that the ZX81 is operational. You should only connect the Chroma interface to a ZX81 that you are confident is in working order else damage may occur to the Chroma interface.