I have a sony tc rx70es cassette deck, one thing is puzzling me, when i swich the deck on at the mains there is a loud thump through the speakers, ie deck itself is off and amp which is on, is working through another input, it could be any eg cd or aux not the selection for the tape deck, a friend pointed me in the direction of the line mute circuit in the tape deck, could he be correct.
in relation to the mute transistors no voltage spec is given in service manual, as for the small cap i wouldent know where to fit it, sorry for the big diagram i dont know how to make it smaller
did some checking in that area, did not find any faults with either transistor or the 6 resistors associated with them, however whilst "poking around" i did find a transistor with a short between base and collector, tested in circuit, and that was q706 a 2sa1317 which is in the power section, hmmm
the main board in this player differs from the one in the sm, a few things from what i have seen are as follows part no 1-634-366-12a which is on this board, d715 is in a different place, d718 is missing, c715 is in a different place and r728 is missing, jumper wire between c708 and c709 is missing, there are no through holes where those parts should be in relation to the sm, c715 and d715 are just below q710 on this board, wonder if this was a problem with this board to start with and this model was either recalled or revised.
q710 is in the correct position.
q710 is in the correct position.