Sinclair power supplies
The "UK 700" supply is suitable only for the ZX81 (and possibly ZX80?) and not the Spectrum as it only delivers 0.7A.
The UK 1200 supply is only suitable for 16K ZX Spectrums, and not 48K machines.
A batch of 28,000 Sinclair power supplies were recalled on the 26th February, 1983. This affects supplies with black and white leads only and with reduced grip on the jack. The faulty supplies have their 240V AV input line too close to the 9V DC output line, resulting in a risk of electric shock in humid conditions. Unaffected supplies matching the description of the faulty batch have a label attached by Sinclair to note that they had been rechecked since the recall.