I have an old Lauda thermostatic water bath (from 1978 or so) that worked fine but suddenly lost temperature control (no cooling). The relay appears to have failed. I have removed it and have googled up and down but the RHL 401-03, 6V 1004 24V does not seem to be available at all. A picture is attached. Its dimensions are 36x30.5x15.5 mm Does anyone have any idea as to whether there might be a source for older relays, or whether there is a suitable substitute? Many thanks.