[DMcMahon]

Power supply ripple checked out OK, the regulated +18V output at C701 was a clean 500mV 100Hz (10mS) and the unregulated +16V at C704 was <5mV 100Hz.

The 2 channels both at headphones output and DIN outputs with music are very clean, with music switched off there is up to 150mV 50Hz noise present. But the noise does not change at all when the DIN to phono cable is unplugged from the deck (cable still connected to scope) and with cable connected the amplitude of the noise signal increases noticeably with the deck switched off.

So unsure how real this noise signal is, maybe it is just phantom pick-up noise, I wish I had a Spectrum Analyzer to check it out more properly.

While checking things out noticed there was a diode lying flay being squashed down by the cable loom at the amplifier PCB. So partially lifted up the board to examine and reposition the diode. To lift the PCB up a little had to remove 4 connectors and their paper ident labels all fell off so reglued them back on once worked out which was which.

At this stage took the opportunity to spray contact cleaner down the end of the Play/Record switch.

Found that the hum type noise could be varied a lot depending upon the orientation of the deck and found by lifting the deck up off the surface it is sitting on, that the hum could be virtually eliminated (the scope noise did not change at all).

With the deck out of its case the underside of the amplifier PCB makes contact with the surface the deck is on so will refit the plastic case to see if hum then is present.

David