Questions you should ask when buying a used SSL

If a warranty is offered, how long is it and what does it cover, or more to the point what does it not cover? Check the exclusions, many warranties only cover parts and exclude power supplies and computer boards.
What condition are the switches in, especially the routing?
What condition are the capacitors in? Any console from the early 1990’s or before need some re-capping.
Are the console power supplies fitted with modern bridge rectifiers with screw terminals? The old black square ones and the round BBC ones have poor connections which tend to overheat and corrode, and they are generally unreliable.
What do the faders feel like? These consoles have Penny & Giles faders which seldom need replacing, but on older desks usually need to be stripped, cleaned and re-lubed, a time consuming job but then they’ll be as good as new. This is particularly important with moving fader desks.
Does it come with a spare channel?
Does it come with a channel extender? Essential for maintenance.
What is the length of the power supply and computer cables – obviously you don’t want them too short but also if they’re too long it can be a problem to fit in the cable duct. Standard lengths are 10m & 15m and occassionally 20m.
Are the power supply and computer fans working properly? Keeping everything cool prolongs their life.
Is it possible to get it into your control room? All these desks are very modular in construction and can be split for transportation, later desks had split points built in.
Lastly you might want to know about the cosmetic condition.