Hello!
I have picked up a broken Yamaha Rev 5. I have recapped the power supply and now it powers up and works, most of the time...
I have noticed intermittent noise on the input single, this noise is most likely to appear just after power up. After probing I've found the point at which the noise is introduced to the input signal (see schematic).
I think the component at fault is the active low pass filter (LPF101), a LP20C9B6. I can't find much on this device other than this datasheet:
Finally, below is an image of my oscilloscope probe connected between C129 and R113, when in fault a 1.2Vpp sine wave appears with a frequency of about 156.8kHz, which disappears when the audio noise stops.
I have also probed +15, -15V and pin 7 of IC101, no sine/noise can be seen.
I am wondering if anyone has also encountered this fault. Does anyone know a source, replacement or clone for an LP20C9B6? Or any recommendations for what I should do next? Many many thanks.
Volter
I have picked up a broken Yamaha Rev 5. I have recapped the power supply and now it powers up and works, most of the time...
I have noticed intermittent noise on the input single, this noise is most likely to appear just after power up. After probing I've found the point at which the noise is introduced to the input signal (see schematic).
Finally, below is an image of my oscilloscope probe connected between C129 and R113, when in fault a 1.2Vpp sine wave appears with a frequency of about 156.8kHz, which disappears when the audio noise stops.
I am wondering if anyone has also encountered this fault. Does anyone know a source, replacement or clone for an LP20C9B6? Or any recommendations for what I should do next? Many many thanks.
Volter
Statistics: Posted by Volter — Wed Mar 12, 2025 1:06 pm — Replies 4 — Views 81