REGA Mira 3 amplifier trouble

Dear audiophiles and electronic enthusiasts
I have a rega mira 3 and a speaker set My rega just Humm and does not give any response for none of the inputs . The volume knob works and input selector works fine also.
Even I check the left and right side terminals with my ohmmeter I read 4 ohms each .(speakers not connected) and the worst the amplifier heatsink becomes hot by the time.
Any suggestions or check point for my issue ?
thanks in advance
Check the power supply voltages, and output devices.
Check the speakers on another amp, that seems unlikely given that you are seeing continuity.
A photo and schematic will be useful.

British design, possibly made in China to a price.
Recap and modification may be needed, check the cost.
Then decide.