My display is black when I turn it on
My SR 7300 is black in display but power going in you can her it klick butall black and no sound can ifixit?
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Hi,
A “click” may be the protection relay operating to prevent damage to the receiver because of a fault, although usually the display lights up and shows “protect” when this occurs
Here is the No Power troubleshooting flowchart, taken from the service manual which may be a good place to start. The manual has full schematics and a parts list to help you further
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The click you hear is the main power relay activated by 9V. 9V is only used for this relay.
That applies power to the main transformer via a fuse on P854 and to the switched AC outlet. If that outlet powers on after the click then the relay is good.
The main transformer supplies power to everything else including the front panel lights. The most probable cause is a blown F851 fuse. If it is blown, you must check for shorts in the power supply. Fuses rarely blow out because they are old.
There appears to be an fuse internal to T001, probably a thermal fuse. Disconnecting W861 and measuring Ω between 1 & 2 of W861 will tell you if that ckt is OK.
The power diodes connected to the transformer, the filter capacitors and the load resistance on each circuit on P804 must be checked. (Ckt on left side of page 9.)
If there are any shorted diodes or not verify that all the power amp output devices are not shorted.
You can then replace the fuse and see if there is any magic smoke.
BTW - if a glass fuse is very dark, as in burned, it indicates the failure was a severe instant overload, maybe a short. If the fuse is just open with no blackening, then either the overload was minor or the fuse just got tired and quit.
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