PhantomBox 1 October 2009 diyaudio.com, pioneer,
This might not be the most indicated place, but I'll give it a shot anyway:
I have a Pioneer SX434 receiver amp (schematics at http://fileshare.eshop.bg/downloadsm/36776/Pioneer_SX-434.html). This is a great sounding amp so I'd like to keep it.
Here's the thing:
Right channel sounds ok but left channel doesn't. On the AWK-034 (power amp section) I replaced Q16 (2SC1318), Q20 (2SD131) and Q22 (2SB507) - all transistors went short - as well as R73 (18ohm 1/2W) - burnt out. I also checked R83 / R85 and R79 / R81 and they are fine.
But I still got no output. Instead it makes a harsh hum sound.
Am I missing something?
compare things to the working channel check the power supply ra
compare things to the working channel
check the power supply rails
work your way through the signal path
find the spot where things change
that pdf file you pointed to is a PCB layout and not a schematic
makes things a little hard to visualise the topology