Yes it's true that the 940 series ATS Group 7 & 9 controllers have been around for quite a while and there still is a lot of them out there in service. Factors such as routine Preventive Maintenance, routine transfer testing, environment, indoor or outdoor (if outdoor NEMA 3R then is the space heater working ?), loading, etc have a lot to do with the service life of the switch. One factor that wasn't mentioned here in determining whether to repair or replace is the size (amperage) of the switch. What we find is the cost to repair is cheaper on units between 600A to 4000A rather than replacement. So based on what we have heard, you have 400A units and the cost to add the 31F pre-signal option to the Group 7 we recommend replacement with the Group 5, 7000 series ASCO's. Or.......... we can sell you a GE-Zenith ATS (now ABB) Lol!
On a side note, ASCO has always had the policy to sell you either a Group 7 controller upgrade (which would include the presignal contact signals) or a new switch, even before all the buyouts by other companies (B-K, Emerson/ Liebert (now Vertiv), Schneider.) This is true even if the failure was due to a faulty timer. On the older switches (906, etc) with relay logic, we have replaced bad timers, relays with the new solid state versions instead replacing the whole switch. But these were usually units above 400A that saved the customer a lot of $$$. ASCO reply was always we can't warrant it because they make more money their way. We have also designed and added presignal controls to the Grp 7 controllers even after ASCO stopped supplying this accessory ad-on panel. A lot of things to be considered here!
