I have two denon dm38dab systems, and one has started cycling through on then off then standby. I would very much like to keep it if i could have it repaired, because it still sounds great. Ive moved to ireland but could take it anywhere in ireland or the uk for a repair...
The cost of repairing old units like this is likely to exceed the cost of buying a later model s/hand unit. If you want to get them repaired then any competent consumer electronics repair shop could do it.
I have just had a sub repaired by a local firm so there may very well be someone close to you that will have a look and give an estimate. What it will cost would be a lottery depending on what is needed. Mine was simple just a resistor blowing.