Mico
Well-Known Member
I have just recapped amp modules on Yamaha CA-1000 replacing three electrolytic caps.
Everything seemed fine, easily adjusted 15V on both sides, A/B and A class idle currents are stable as well and DC offset on the right side. But left side DC is acting up, on cold startup it takes off from -150mV and than starts the countdown: in about 5min DC drops to - 65mV and continues to move in that direction.
After 15min. value is already zero , only to stabilize around 15-20mV. when full operating temperature was reached. Relay clicks in immediately even at -150mV so all this does not trigger protection. DC is the same regardless of the operating mode (A/B or class A) and amp/preamp bridge has been disconnected.
Never seen this before and not 100% sure if it was the same before recap, probably not as I would have noticed the extreme.
Everything seemed fine, easily adjusted 15V on both sides, A/B and A class idle currents are stable as well and DC offset on the right side. But left side DC is acting up, on cold startup it takes off from -150mV and than starts the countdown: in about 5min DC drops to - 65mV and continues to move in that direction.
After 15min. value is already zero , only to stabilize around 15-20mV. when full operating temperature was reached. Relay clicks in immediately even at -150mV so all this does not trigger protection. DC is the same regardless of the operating mode (A/B or class A) and amp/preamp bridge has been disconnected.
Never seen this before and not 100% sure if it was the same before recap, probably not as I would have noticed the extreme.
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