I am working on this receiver for my son. No sound, except for a little bleed through. I do get sound through the preamp and the phono amp, so I know that part is working; however, the tuner is not working. +12v line is 4.6v going to the tuner (and probably everywhere else). I get 4.6v at the output of the positive 12v regulator. The -12v regulator output is okay. It seems like there are a lot of places the 12v could be shorted in this receiver. Has anyone seen this problem, or if not, point me in the right direction? I am kind of stumped right now. Thanks in advance for any help.
Sony STR-D650Z Stereo Receiver
Dec 11, 2005
5 Replies
If the 12V line were being loaded down that much the regulator should be so hot it will burn the skin off your fingers as soon as you touch it.
If there is not excessive load then the regulator will not be so hot and there is a problem in the regulator circuit somewhere.
Agreed. On many occasions, I have had these 7812 monolithic regulators, go low output. 4 odd volts is about the level you do get out from them when they do this. If the regulator is not red hot ie being loaded into thermal shutdown by an external fault, just replace it.
Arfa
IF you decide to replace the regulator, check the capacitors on the input and output pins (leakage, bulging, etc.) to the regulator -- good time to replace these - if problematic.
gb
Thanks for adding that gb, I should have said. You tend not to think to say these things when you normally do it yourelf as a matter of course.
Arfa
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