At last I have got the 6CW4 tuner working
.
The culprit was one of the two "NOS" ECC85 is bad. I have replaced the bad ECC85 by 6BS8 for the oscillator, it comes alive suddenly. The tuner is now working very well with good sensitivity and selectivity. I wire it to the IF input of an existing stereo tuner. It retains very good stereo fidelity. The other modification is that I have drilled bigger holes near all three silver-plated coils. My theory is that the proximity of the coils near the copper ground plane would dampen the oscillation and lower Q of the coils. Copper is far more conductive than aluminium. At VHF frequency, the induced eddy current on the copper plate opposes the magnetic field from the coil reducing its inductance.
Anyway I am happy with it.
