I am repairing one of these for a studio. There is an intermittent fault where the unit doesn't power up at times. The power supply is linear so it should be easy to solve, but so far has eluded myself and Guy (another tech.). It suddenly comes to life with the slightest provocation, but there are no dry joints, or loose connectors to be found. Puzzling - I'll keep on the case.
The TC 2290 is no longer made (they started in the 1980s) but they are still considered by many to be the pinnacle of digital delays - both for the sound quality, and all the features. I think this was the first delay to have 'tap tempo'. It is named Learn, and samples the delay between two pushes of the Learn button.
There is a website dedicated to the 2290 here.