Samsung ML1660 intermittant switch on

Hi All,
As in the subject, I have a Samsung ML1660 which has been fine until recently.
This item now has become difficult to switch on, ie. the SMPS will not start and all I see is a very brief flash of the indicator LED's when pressing the 'on' button.
I waqs wondering if anyone has had this issue before and resolved it.
I have downloaded the SM but there is no schematic of the PSU.
In days gone by, there used to be a start-up resistor in this type of PSU and was wondering if this is still the case.
I've not opened up the printer yet as have not had the time too look but wondered if anyone has any pointers / clues as to what could be failing.
Will try to find time this week to take a look.
Any help at all would be most useful.
Thank you for reading.