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Pioneer sx-680 right meter spikes, large pop in speaker

Unsolder and disconnect (lift) one end of D504. Remeasure DCV on the - side of C512. If you still have +6vDC there pull C512 and measure DCV on the pad where the - side of C512 was. Also measure DCV on the pad where the + side was.

EDIT: more
 
Last edited:
merlynski said:
Unsolder and disconnect (lift) one end of D504. Remeasure DCV on the - side of C512. If you still have +6vDC there pull C512 and measure DCV on the pad where the - side of C512 was. Also measure DCV on the pad where the + side was.

EDIT: more
Click to expand...

So I pulled 1 side of D504 and measured volts at the C512 side and it was 0vdc.
I also measured D504 opposite side of C512 and it was 5.44vdc
 
Dlrockey76 said:
So I pulled 1 side of D504 and measured volts at the C512 side and it was 0vdc.
I also measured D504 opposite side of C512 and it was 5.44vdc
Click to expand...

I do not understand this. D504 is not connected to C512.
Keep the black lead attached to the chassis. With the red lead:
Measure DC volts on the - (negative) side pad of C512:
Measure DC volts on the + (positive) side pad of C512:
 
merlynski said:
I do not understand this. D504 is not connected to C512.
Keep the black lead attached to the chassis. With the red lead:
Measure DC volts on the - (negative) side pad of C512:
Measure DC volts on the + (positive) side pad of C512:
Click to expand...

So the - side of C512 is 0vdc
+ side of C512 is 6.88vdc
 
OK, got it! Those voltages look OK.
Is C512 in or out?
If out and you have a new replacement, install it, otherwise it is fine.
Check at C302 (and the meter) for the spike when switching the Function switch (leave D504 lifted).
 
merlynski said:
OK, got it! Those voltages look OK.
Is C512 in or out?
If out and you have a new replacement, install it, otherwise it is fine.
Check at C302 (and the meter) for the spike when switching the Function switch (leave D504 lifted).
Click to expand...

I already replaced C512 when I first got the receiver. I rechecked C302 voltage with D504 half removed. No spike when D504 is half removed. Cant check meter for spike cause I still have C301 coupling cap removed
 
C301 is the left channel preamp to power amp coupling cap, C302 is the right channel coupling cap. Having C301 removed should NOT affect the right channel; meter or speaker pop. Put C301 back in.
Reinstall/replace everything that was removed, except leave D504 lifted and then recheck for spike on right channel meter and speaker pop.
If spike/pop is not present replace D504 and test again. A 1N4148 will work there.
 
merlynski said:
C301 is the left channel preamp to power amp coupling cap, C302 is the right channel coupling cap. Having C301 removed should NOT affect the right channel; meter or speaker pop. Put C301 back in.
Reinstall/replace everything that was removed, except leave D504 lifted and then recheck for spike on right channel meter and speaker pop.
If spike/pop is not present replace D504 and test again. A 1N4148 will work there.
Click to expand...

So I was confusing C301 & C302. It was C302 that was removed. It also means the info I gave u about C301 & C302 would have to be swapped. I replaced C302 with a new cap and rechecked voltage.
C302 Normal voltage was 1.9Mv and when I turned it on it jumped to 80Mv for a sec which the meter (which is in watts) only move to about 3/4 of a watt. It was maxing out at over 30 watts originally. I checked C301 for comparison ( which would only read in DCv and not Mv like C302) normal voltage was 6.88vdc. When turning on receiver jumped to 7.2vdc for split sec
 
Dlrockey76 said:
So I was confusing C301 & C302.
Click to expand...
OK, good to know. This remote control troubleshooting can be confusing, happens a lot.
FYI, to help communications be better, a capitol M is the abbreviation for Mega, small m is the abbreviation for milli as in 10mV means 10 millivolts. 10MΩ is 10 Megohms. Lightning bolts are in MV. |:rflmao:|
So you now have a smaller spike than you did before, and that is with D504 lifted? Replace D504 with a 1N4148 (if you have one) or another small signal / switching diode and try it again to see if spike is gone, or still there. Looks like possible progress.
 
merlynski said:
OK, good to know. This remote control troubleshooting can be confusing, happens a lot.
FYI, to help communications be better, a capitol M is the abbreviation for Mega, small m is the abbreviation for milli as in 10mV means 10 millivolts. 10MΩ is 10 Megohms. Lightning bolts are in MV. |:rflmao:|
So you now have a smaller spike than you did before, and that is with D504 lifted? Replace D504 with a 1N4148 (if you have one) or another small signal / switching diode and try it again to see if spike is gone, or still there. Looks like possible progress.
Click to expand...

Thanks for the info I do not have any diodes so I will have to order some. As soon as I get it changed I will recheck and post the results. Thank you so much for your help and patience. It's much appreciated
 
merlynski said:
OK, good to know. This remote control troubleshooting can be confusing, happens a lot.
FYI, to help communications be better, a capitol M is the abbreviation for Mega, small m is the abbreviation for milli as in 10mV means 10 millivolts. 10MΩ is 10 Megohms. Lightning bolts are in MV. |:rflmao:|
So you now have a smaller spike than you did before, and that is with D504 lifted? Replace D504 with a 1N4148 (if you have one) or another small signal / switching diode and try it again to see if spike is gone, or still there. Looks like possible progress.
Click to expand...

So I replaced D504 and the full spike is back. I was hoping that since D504 was partially removed and the spike dropped significantly that D505 was the issue. Disappointing
 
The difficulty with swapping the FETs is that they are easily damaged by static electricity, A static safe work area and a static strap are needed.
If done that way it is a very good idea.
 
merlynski said:
The difficulty with swapping the FETs is that they are easily damaged by static electricity, A static safe work area and a static strap are needed.
If done that way it is a very good idea.
Click to expand...

So I pulled out the 2sk117 on the left and right and I reinstalled the left one (good side) on the right side (bad side) and the spike is gone. It's gone when I turn power on and off and it's gone when I switch inputs. I didnt reinstall the bad one on the left side to see if the spike followed cause I assumed if the good one on the right side eliminates the spike then that should be the problem. Do you have a recommendation for a replacement for 2sk117
 
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