For the reason it was $10 (and that I had read it was a decent amplifier) I wound up with a Sanyo P55 MOSFET power amp. The reason it was $10 may have been an assumption one channel was dead. That was the case when using speaker system A but when switched to system B both sides function. I attribute this to a relay but am not going to address that.
Although it was not titled as such in the service manual, what I believe to be the proceedure to adjust bias current required jumping speaker terminals with a 100 watt 8 Ohm resistor. Not wanting to spend the cost for one of those, I used a 25 watt 8 Ohm which I had on hand.
After cleaning the adjustment pots which was needed, I discovered that I could achieve plus or minus voltage while rotating the pots back and forth.
The target voltage was 10mv so I adjusted accordingly, meaning +10mv.
There has not been a huge number of times I've adjusted bias but I don't recall being able to obtain negative voltage. It seems to me that the lowest voltage achievable was zero.
Just wondering if variance from negative to positive voltage is common place.
There was a secondary adjustment described in the manual. By using a different pot per channel, it's objective was obtaining a sum of 50mv as measured across two per side 5 watt 470 Ohm ceramic resistors.
After performing the above, the result was 13mv. & 63mvi DC offset.
One other thought. To make the first adjustments described, where the goal was 10mv with 8 Ohm resistors across speaker terminals, I had my meter set at DC. Since it was not measuring DC offset per se, should it have been at AC volts?
Although it was not titled as such in the service manual, what I believe to be the proceedure to adjust bias current required jumping speaker terminals with a 100 watt 8 Ohm resistor. Not wanting to spend the cost for one of those, I used a 25 watt 8 Ohm which I had on hand.
After cleaning the adjustment pots which was needed, I discovered that I could achieve plus or minus voltage while rotating the pots back and forth.
The target voltage was 10mv so I adjusted accordingly, meaning +10mv.
There has not been a huge number of times I've adjusted bias but I don't recall being able to obtain negative voltage. It seems to me that the lowest voltage achievable was zero.
Just wondering if variance from negative to positive voltage is common place.
There was a secondary adjustment described in the manual. By using a different pot per channel, it's objective was obtaining a sum of 50mv as measured across two per side 5 watt 470 Ohm ceramic resistors.
After performing the above, the result was 13mv. & 63mvi DC offset.
One other thought. To make the first adjustments described, where the goal was 10mv with 8 Ohm resistors across speaker terminals, I had my meter set at DC. Since it was not measuring DC offset per se, should it have been at AC volts?
SVR702/802 adjusts the quiescent current.
No load resistor should be used or loudspeaker when making this adjustments.
SVR701/801 adjusts the zero voltage null and that is when a load resistor is used. A 10R 5Watt is fine. Adjust for minimum voltage across the load resistor less than 10mV in either polarity.
No load resistor should be used or loudspeaker when making this adjustments.
SVR701/801 adjusts the zero voltage null and that is when a load resistor is used. A 10R 5Watt is fine. Adjust for minimum voltage across the load resistor less than 10mV in either polarity.
Thanks!
The resistors were not used adjusting SVR702/802, only the other. Thinking it might be significant, I ensured SVR701/801 voltages were on the + side.
I thought it would have made a difference. Surprised that it's irrelevant.
The resistors were not used adjusting SVR702/802, only the other. Thinking it might be significant, I ensured SVR701/801 voltages were on the + side.
I thought it would have made a difference. Surprised that it's irrelevant.
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