During his time with Magazine McGeoch played a Yamaha SG1000 guitar with a stand-mounted MXR M117R flanger. He bought his first model in 1977 when the band signed its recording deal, which provided him with the finances for professional standard equipment. Whilst with Siouxsie and the Banshees he created his own setup, involving an MXR flanger mounted on a mic stand which allowed him to hit a chord and sweep the flange knob in real time. Whilst working with 'The Armoury Show', he also used a Squier 1957 Stratocaster and an Ibanez AE410BK. During his work with PiL, and in his last years he favoured a solid wood Carvin electric guitar. He also used a Washburn Tour 24 guitar for touring during 1988.
Detailed in this April 1986 issue of International Musician: http://www.muzines.co.uk/articles/tinder-is-the-night/5160
"John McGeoch 1980-83. Played on Kaleidoscope, JuJu and Kiss In The Dreamhouse Equipment Yamaha SG1000 12 String Ovation (Usually DI'd) MXR Flanger MXR Dynacomp Compressor Yamaha Analog Delay Two Marshall MV50 combos* Roland JC120*"
John can be seen playing the guitar during this performance of 'Shot by Both Sides' with Magazine on the Belgian TV series Follies in 1979.
In the first paragraph on this page of this interview, John McGeoch says, "After that I shopped around for a vintage Strat and checked out some new ones and of all of them I preferred the Squier '57 Strat."
John can be seen throughout this video playing a Ibanez AE410BK.
John can be seen playing the Ovation 1618 Glen Campbell 12-string in this image. The guitar can also be seen with Siouxise and the Banshees in the official video for "Spellbound" at :30s.