Cambridge Instruments Plc shares returned from suspension yesterday at a lowly 34 pence against a pre-suspension price of 44p (CI No 872) after it announced that profits for the year ending March 31 1988 are likely to be well below those expected due to a shortfall in orders caused by deferred purchasing following the stock market crash, difficult trading conditions in the semiconductor market and an unfavourable US exchange rates: the company is also grappling to put the US optical microscopes maker it acquired last year, Bausch & Lomb, on a firmer footing, but according to one City analyst Cambridge Instruments is fundamentally sound with a net debt level at no more than 30% of shareholders funds.