Derek O
New Member
Hello!
I've owned an sx680 for about 4 years and has been great. I recently shipped it from my home town to where I live, and it worked fine for about a week and then stopped working.. No sound from the speakers from the AUX input.
I've since taken it apart, and tested voltage throughout noticing that on the power input side, there has been issues around Q402. The Base voltage was showing 16V and showing 0V on the Emitter - I took out the transistor and replaced it with:
2sc1384 replaced with 2SD669A NPN - 180V 1.5A
Once replaced the base was properly reflected on the emitter voltage for Q402 - but the base voltage was incorrect. Sitting at 19.8V instead of the expected 45V shown on the diagram.
After replacing pretty much everything related to the base voltage of Q402:
R401 - 33 ohm 1/2W
R406 - 8.2k ohm 1/2W
D409 - 1n4148 fast switching diode
R347 - 100 ohm 1/2W
I'm still seeing only 19.8V on the Base of Q402. Measured values near Q402 are as follows:
IN for R403: 51.7V
OUT for R403: 51.3V
IN for R406: 51.3V
OUT for R406: 19.8V
IN for D409: 19.8V
OUT for D409: 19.8V
Q402:
E: 19.2V
C: 51.4V
B: 19.8V
One condition that changed once I replaced the transistor is that I now hear a low volume on my speakers when volume put at MAX.
I'm wondering if any amazing people here can help figure out what might be the issue now? I have a feeling a capacitor has shorted or is pulling extra voltage (maybe C406? or C404?) and dropping the voltage at R406. I tried pulling out C406 but seems pretty stuck in there.. are they glued or sealed to the board? A little worried about pulling the Cap too hard. Definitely seems like the 21V drop across R406 is the issue, but I don't know what else to check at this point. Total rookie with this stuff and am taking this as a learning opportunity, so hopefully you guys can help!
Thanks a ton for any help!!!
I've owned an sx680 for about 4 years and has been great. I recently shipped it from my home town to where I live, and it worked fine for about a week and then stopped working.. No sound from the speakers from the AUX input.
I've since taken it apart, and tested voltage throughout noticing that on the power input side, there has been issues around Q402. The Base voltage was showing 16V and showing 0V on the Emitter - I took out the transistor and replaced it with:
2sc1384 replaced with 2SD669A NPN - 180V 1.5A
Once replaced the base was properly reflected on the emitter voltage for Q402 - but the base voltage was incorrect. Sitting at 19.8V instead of the expected 45V shown on the diagram.
After replacing pretty much everything related to the base voltage of Q402:
R401 - 33 ohm 1/2W
R406 - 8.2k ohm 1/2W
D409 - 1n4148 fast switching diode
R347 - 100 ohm 1/2W
I'm still seeing only 19.8V on the Base of Q402. Measured values near Q402 are as follows:
IN for R403: 51.7V
OUT for R403: 51.3V
IN for R406: 51.3V
OUT for R406: 19.8V
IN for D409: 19.8V
OUT for D409: 19.8V
Q402:
E: 19.2V
C: 51.4V
B: 19.8V
One condition that changed once I replaced the transistor is that I now hear a low volume on my speakers when volume put at MAX.
I'm wondering if any amazing people here can help figure out what might be the issue now? I have a feeling a capacitor has shorted or is pulling extra voltage (maybe C406? or C404?) and dropping the voltage at R406. I tried pulling out C406 but seems pretty stuck in there.. are they glued or sealed to the board? A little worried about pulling the Cap too hard. Definitely seems like the 21V drop across R406 is the issue, but I don't know what else to check at this point. Total rookie with this stuff and am taking this as a learning opportunity, so hopefully you guys can help!
Thanks a ton for any help!!!
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