Hello everyone, how are you ?, I got an amplifier LSV PM-6960 which turns on but you can not hear or see it react to anything when I try to change the work modes and / or signal source. It also has the problem that if I turn up the volume quickly then it activates the internal relay and deactivates it a few seconds later, then I try to increase the volume again and by doing the same procedure above the relay is activated again, deactivating again after a few seconds. So far I verified that the transformer gives 30VAC where the card indicates 27 or 28VAC., It has the + 14VAC and -14VAC and the 5VDC reaches the tiny radio and / or audio card but there is no reaction when I press the radio buttons / usb or input channel. I found a kind of calcified or something similar on several cards, even on the inside of the case. It will have got wet ?. What additional tests can I do to verify that the different stages are working and thus be able to rule out points of failure? Attached photos. What I think is a calcification on the output card. What I think is a calcification on the inside of the housing. The blue card is the radio / audio / usb card.

check the exciter transistors, 9014, 9015, 5551 that are in good condition, check the part of the prelude, the zener diodes and diodes of the plate, and the outputs of the plant, if there is any short that seems to be so, any of these pieces will surely indicate From my own experience, verify that the wires that bridge the board are good, there is no match, I pass one that hit the relay, it was making an electric sound but never activated, and obviously did not sound, and it turned out that one from the bridges it rusted and broke and towards the fault, good luck my friend