Channel out

[rhymeswthorange]

My Paciific Stereo Concept 6.5's right channel is out. When I tap a thermal fuse (white radial box w/ paste) attachted to the power amp heatsinks, it sometimes comes back to a brief, quiet, crackly life. My question is, does this seems characteristic of a blown fuse? To have one channel work and the other not seems like something else... wouldn't it just not work at all if the fuse was blown? Also, it seems that the preamp section is the culprit - when i touch an input to the power amp, there is a strong hum on both channels. Any ideas? Thanks!

 

[richie00boy]

A white radial box could also be an 'emitter' resistor which is part of the output stage.

 

[rhymeswthorange]

This particular box was pasted onto both heatsinks and has the markings: "U12 125V 6A 83 95C UCHIYA"

 

[Tube_Dude]

When I tap a thermal fuse (white radial box w/ paste) attachted to the power amp heatsinks, it sometimes comes back to a brief, quiet, crackly life.

It seems to me , that white radial box is a thermal breaker, that stay always open, try to measure it with a multimeter in Ohms , it need to measure near 0 Ohms, at ambient temperature.

Regards.

 

[rhymeswthorange]

Well... the fuse isn't blown, any suggestions on how to proceed?

 

[clem_o]

Look on the underside of the board and start resoldering. You can try tapping components / board gently with a pencil, and try to find the spot most sensitive to the mechanical vibrations.