MHR
New Member
Hi all,
I have an issue with a Pioneer SA-710. First of all, the amplifier works fine, but with my IR-gun I can see several parts getting way too hot. R113 and R114 60+ and have a huge voltage drop of 20V and power dissipation of 0.8W. In the Phono stage Q5, Q6 and R25 and 26 get really hot as well, although voltages check out on those transistors, but maybe the current is too high? So I thought there were leaky transistors or capacitors, so I changed them all. Although the amp runs a bit cooler now, the problem persists. Also Q7 and Q8 should have an emitter voltage of 5.8V, But I only get 0.6V on both. On the base of these transistors I measured 0.1V, which suggests these transistors aren't turning on properly. So Q7 through Q12 are part of the biasing cirquit right?
So far I can't find a faulty component. Does anyone have experience with a Pioneer SA-710 and what would be 'normal' operating temperatures of the above mentioned parts?
So my question is, is there anyone having experience with this amplifier and if so, is willing to guide me in the right direction? I can give more info when needed.
Kind regards,
Marvin
I have an issue with a Pioneer SA-710. First of all, the amplifier works fine, but with my IR-gun I can see several parts getting way too hot. R113 and R114 60+ and have a huge voltage drop of 20V and power dissipation of 0.8W. In the Phono stage Q5, Q6 and R25 and 26 get really hot as well, although voltages check out on those transistors, but maybe the current is too high? So I thought there were leaky transistors or capacitors, so I changed them all. Although the amp runs a bit cooler now, the problem persists. Also Q7 and Q8 should have an emitter voltage of 5.8V, But I only get 0.6V on both. On the base of these transistors I measured 0.1V, which suggests these transistors aren't turning on properly. So Q7 through Q12 are part of the biasing cirquit right?
So far I can't find a faulty component. Does anyone have experience with a Pioneer SA-710 and what would be 'normal' operating temperatures of the above mentioned parts?
So my question is, is there anyone having experience with this amplifier and if so, is willing to guide me in the right direction? I can give more info when needed.
Kind regards,
Marvin