Yamaha5000
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NISSEI NSK135 .033 + 120ohm
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- nissei snubber yamaha yamaha c-2
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Yamaha5000
Never settle for 2nd best
NISSEI NSK135 .033 + 120 ohm 125vac
Located across Yamaha C2 Power Switch
Located across Yamaha C2 Power Switch
arnold_a1968
Member
i have Yamaha B-4 and having random and frequent popping noise on left speaker with or without input signal.
did an A-B transistor change on Left and Right Power Board and driver board, still there's cracking noise.
There's also this NSK135 on the power switch but could not test if it is damage or what, since it's a series RC filter my multimeter cannot do the test.
Any suggestion how to know if this is defective or causing the crack noise.
did an A-B transistor change on Left and Right Power Board and driver board, still there's cracking noise.
There's also this NSK135 on the power switch but could not test if it is damage or what, since it's a series RC filter my multimeter cannot do the test.
Any suggestion how to know if this is defective or causing the crack noise.
arnold_a1968
Member
what issue you have with your C2, i have not open up my C4 but probably it has same NSk135
Sounds like noisy transistor or diode to me. Doubt very much if the snubber RC network is the problem. Both channels would be popping if it was the snubber.
Could it be a bad relay ? I had that on an A-1 , no input and it pop and crackle etc.
Nashou
Did you try both speaker A and B.. There are two separate protect relays in the B-4. One for A and one for B. If it " crackles " in both. the relay itself is not the problem. Solder connections perhaps..
arnold_a1968
Member
tried many things on this B-4, diode test all the transistors and diode, pull out most of them that kind of suspect but all good, A-B swapepd some of it but still left cracks.
Cleaned the relays for the speaker relay and power relay for both A and B. I monitored the output with 1Khz signal input but the output signal waveform is very clean for an hour
no spurious or white noise appeared on the scope for both L/R output, audio wise the music is so clear but there's a random added pop/crack only on the left channel.
i even swapped the rectifier diode of L/R though all the diode are fine on diode test, change the mylar capacitor but still the Left channel cracks.
there's no complete schematic available online but i checked the power switch has RC snubber on both lines that goes to transformer A and B so that's one thing i thought the RC snubber maybe causing that crack on the left side.
and there's another suspect, on the speaker impedance, on the left side, i'm seeing a -0.3V whereas on the right +0.1V and when i slide the impedance slider, the output waveform of the left swing somehow on up/down while the PK-PK is constant unlike the Right channel the output waveform is stable, does not swing. I'll focus on this impedance matching circuit if i change the RC snubber with no improvement.
Cleaned the relays for the speaker relay and power relay for both A and B. I monitored the output with 1Khz signal input but the output signal waveform is very clean for an hour
no spurious or white noise appeared on the scope for both L/R output, audio wise the music is so clear but there's a random added pop/crack only on the left channel.
i even swapped the rectifier diode of L/R though all the diode are fine on diode test, change the mylar capacitor but still the Left channel cracks.
there's no complete schematic available online but i checked the power switch has RC snubber on both lines that goes to transformer A and B so that's one thing i thought the RC snubber maybe causing that crack on the left side.
and there's another suspect, on the speaker impedance, on the left side, i'm seeing a -0.3V whereas on the right +0.1V and when i slide the impedance slider, the output waveform of the left swing somehow on up/down while the PK-PK is constant unlike the Right channel the output waveform is stable, does not swing. I'll focus on this impedance matching circuit if i change the RC snubber with no improvement.
Static transistor & diode checks will not identify a device that fails under circuit load.
arnold_a1968
Member
it's just very difficult to poke each component as this B-4 has no enough space to get the probe in but i did a swap and no change on L crack
arnold_a1968
Member
yup, not the snubber, much easier to trouble shoot if it's just totally dead, it's easy to trace unlike this random cracking noise,
how about those pesky mylar capacitor across the speaker relay?
how about those pesky mylar capacitor across the speaker relay?
Nope..
Concentrate on the left channel amplifier...
Post some photo's.. Better yet.. Start your own thread . Instead of crapping in this thread..
arnold_a1968
Member
I'll start a thread and hope to get all your inputs..Thanks
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