Linn LK100

An Old Chestnut,

I have an old Linn LK 100 that is cutting out minutes after switch on. I have seen posts on this before and have followed some of the advice in faulting the board but everything I have changed makes little or no difference. Basically I need some further help to cure this issue

I am working from the cct diagram previouly posted, but I don't have a diagram for the power supply or a complete schematic.

I have the +/- 40 volt rails.

The = +30v rail is reading +32.6 volts approx and the - 30v rail -29.5 volts.

The DIS point is + 42 volts when amp is working and swings to - 28 volts after cutting out.

I have changed most of the capacitors, diodes, transistors up to Q207,Q209, Q307,Q309 respectively and I am unable to find as yet a faulty component and the same fault remains.

Any help or advice would be welcome.