I found the problem was with the PWM chip (in this circuit diagram the TOP264). My circuit had the variant IW1760 chip which could also be rewired and utilised with the IW1710 chip which are readily available.
Once the chip was replaced the bi-stable operation allowed an AC source to be applied to the output transformer and completing the circuit operation.
Please see attached circuits for comparison.
[file]https://file.remont-aud.net/comment/files/08-03-26-23-03-23_TOP264.zip[/file]