Greetings all,
I have hit a wall trying to figure this schematic out, it isnt marked clearly enough for me to determine what everything is supposed to be, and am wondering if anyone here knows what the values should be for b1 through b5 on the output side of the power supply board.
heres the story:
I got this today, the previous owner said first one channel died, and he used it as a single channel receiver until the other one died, tho they arent fully dead if you turn the volume up to around 70% you can still hear it, quietly, any higher than that and it starts making popping noise through the speakers though.
what ive done thus far: using another receiver with preamp out I connected to the main-in of this one and verified the amp is ok.
deoxited all knobs and switches including the one in the back for the preamp.
checked various transistors on all boards for shorts, none found. (in circuit checks)
verified it does this in multiple input modes (fm and aux in this case)
scanned thoroughly for obvious broken connections, resistors to chassis, solder joints on preamp, control, and power supply boards
ive also measured the voltage (chassis ground) of b1-5 on the power supply board and got the following results:
b1=70.3v b2=40.3v b3=32.55v b4=18.3v b5=12.71v
I (think) b1, 3, and 5 are correct? but im not sure because im new to reading these manuals.
if anyone out there can assist me with this and let me know what the values should be, that would be excellent.
also, any theories on why its doing this are also welcome.
many thanks in advance.
-Don
I have hit a wall trying to figure this schematic out, it isnt marked clearly enough for me to determine what everything is supposed to be, and am wondering if anyone here knows what the values should be for b1 through b5 on the output side of the power supply board.
heres the story:
I got this today, the previous owner said first one channel died, and he used it as a single channel receiver until the other one died, tho they arent fully dead if you turn the volume up to around 70% you can still hear it, quietly, any higher than that and it starts making popping noise through the speakers though.
what ive done thus far: using another receiver with preamp out I connected to the main-in of this one and verified the amp is ok.
deoxited all knobs and switches including the one in the back for the preamp.
checked various transistors on all boards for shorts, none found. (in circuit checks)
verified it does this in multiple input modes (fm and aux in this case)
scanned thoroughly for obvious broken connections, resistors to chassis, solder joints on preamp, control, and power supply boards
ive also measured the voltage (chassis ground) of b1-5 on the power supply board and got the following results:
b1=70.3v b2=40.3v b3=32.55v b4=18.3v b5=12.71v
I (think) b1, 3, and 5 are correct? but im not sure because im new to reading these manuals.
if anyone out there can assist me with this and let me know what the values should be, that would be excellent.
also, any theories on why its doing this are also welcome.
many thanks in advance.
-Don
B1 76v. B2 40v, B3 28v, B4 18v
Page 17/18 service manual.
Low volume is probably headphone socket.
Page 17/18 service manual.
Low volume is probably headphone socket.
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oi, for some reason i thought i had the service manual and it was just lacking important details... definitely no page 17 in this pdf i have, though.
thanks for the info.
so with those values being so close to right, its probably not the power supply board causing the problem then, unless a couple of volts over is enough to do it?
i have a (cheap) esr meter so tomorrow im going to start checking for bad caps on various boards, theres definitely a problem somewhere, ill find it eventually.
thanks for the info.
so with those values being so close to right, its probably not the power supply board causing the problem then, unless a couple of volts over is enough to do it?
i have a (cheap) esr meter so tomorrow im going to start checking for bad caps on various boards, theres definitely a problem somewhere, ill find it eventually.
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