If there are several options, one is to stick to the Ilford model and replace the pad. I know that over time, the parts start to fail; in this case, the controller. It could be the power supply or the filters, or the command for the upper fan, which is an integrated Intel component. Going for newer parts is the right path or the option that will give me at least another 10 years. By Heiland, I discarded it because the cost exceeds my budget. Something from RH is more accessible, or switching everything to LED; in this case, I've only seen Heiland's product and have no idea if there are other brands or market options.
TK