21-05-2015, 04:56 PM
The heat on R405 would seem to be normal, its a 5% ww on stand off tags with holes in the pcb for ventilation under it. Running for an hour its still only 'hot'.
Could find no excessive current draw on the feed to the Y amps. Voltages around TR751,2,3 seem to be as I would expect, TR751 40v col, 29v base, 28.4v emit, TR752 113v col, 27v emit, TR753 105v col, 27v emit. All transistors are OK on test.
Clicking seems to have stopped, maybe it was a wee bit damp around the eht.
I am very confused about the transistors being different when the spec sheet says they should be similar. And being the same when they should be different!
I haven't found any BC109C s on the boards, there should be lots of them.
Example, TR82 should be BC109C, its a FRB749 ( whatever they are ).
But TR75 should be BSX20 but its another FRB749 !
Maybe someone has been here before me.
Could find no excessive current draw on the feed to the Y amps. Voltages around TR751,2,3 seem to be as I would expect, TR751 40v col, 29v base, 28.4v emit, TR752 113v col, 27v emit, TR753 105v col, 27v emit. All transistors are OK on test.
Clicking seems to have stopped, maybe it was a wee bit damp around the eht.
I am very confused about the transistors being different when the spec sheet says they should be similar. And being the same when they should be different!
I haven't found any BC109C s on the boards, there should be lots of them.
Example, TR82 should be BC109C, its a FRB749 ( whatever they are ).
But TR75 should be BSX20 but its another FRB749 !
Maybe someone has been here before me.
Boater Sam.
