If Q101 is very hot D601is probably short or as in the ones that i have come across,leaky.
Q101 provides a stable supply for IC601,12v i think. D601 seems to be a overvoltage protection zenner diode.I use 13v zenner. Unsolder it and measure for reverse leakage,or just change it.If you are unlucky
IC601 may be faulty and it does not seem to be available. The initial cause of problem is electolytic caps in the area of IC101, C103, C104 ect. Replace them all before switching on. Most of them are 33uf.
phil.