whatever can be the input source,the flag " poweroff" apears and switch off the system. Seems to have no time rules, shut down frequency connected with hazard ...... No...
I'm not sure what kind of an answer you are looking for. If you are not qualified to do some soldering rework and ready to spend some money (could be as much as 50$) for parts, you better look for a professional service that in most cases will cost as mush (or more) as your receiver.
If you are still reading then here you are. This is a common symptom of a blown hybrid amplifier IC caused by shorting speaker output while it's powered on. There are two protection circuits for amplifier output, Overload and DC output. In your case, most probably, DC output protection is the one that shuts down amplifier to prevent further damage. Find schematics (service manual). To confirm this, look for amplifier inputs connector, measure DC DET. signal, normally it should be around +4.85V. If right after power up it goes down to almost 0V, then it is for sure a blown output on a Hybrid IC. Check whether receiver shuts down with that cable unplugged. If not than get ready to do some rework.
There are two big Hybrid amplifier ICs, one that outputs two channels (usually front left and front right) and 3 channels (for the rest). One of the outputs (if not more) one one of them (if not both) is blown. In most of the 5.1 Pioneer receivers 2 channel IC is PAC010A and 3 channel one is PAC011A. If you want to get original parts and will find those for less then 40$ each you are lucky. There are however cheaper replacements from SANYO, those you can find for around 10-15$.
Find schematics, unsolder resistors one by one that connect AMP outputs to DC detection circuit on each IC and check which one is blown. There are 2 for 2 channel one and 3 for the other. Usually if one output is blown all others on the same IC are blown.
There could be a chance that only one channel on IC is blown, if you want to fix it you still need to replace whole IC. Also, instead of spending on new IC you may want to sacrifice one working channel (center for example) to output the blown one (so you'll get 4.1 :) ).
Nov 11, 2010 |
Pioneer VSX-D710S Receiver