I found a problem ..
According to the service manual on Q9301 i should have -15.69 volts on the center leg..
Im getting 47 volts
On Q9302 on the center leg i should have 15 volts im getting -47 volts
and on Q4901 on leg 1 i should have -34 volts im getting -47 volts
Any ideas why the voltages are way off?
I cannot seem to track the problem down
According to the service manual on Q9301 i should have -15.69 volts on the center leg..
Im getting 47 volts
On Q9302 on the center leg i should have 15 volts im getting -47 volts
and on Q4901 on leg 1 i should have -34 volts im getting -47 volts
Any ideas why the voltages are way off?
I cannot seem to track the problem down
I have an amp like this in the shop now. A few notes...
The service manual voltages are wrong because they have the wrong pin configuration. The collector is at ground. The base is about 12v above the negative rail. The emitter is about 11.5v above the negative rail. You can place the black probe on the center leg of the negative rail rectifier adjacent to Q4901 to check these voltages.
The Zener should have 12v when the voltage is measured directly across it. The anode should be directly connected to the negative rail. The cathode is directly connected to the base of Q4901 (3rd leg).
The collector of Q4901 is directly connected to ground (primary and secondary grounds are tied together).
The emitter of Q4901 is directly connected to pin 3 of the IR2010S ICs.
You should read approximately 11.5v between pin 15 (black probe) and pin 3 (red probe) on the IR2010S ICs.The same voltage can be read across C9801 and C9802.
The service manual voltages are wrong because they have the wrong pin configuration. The collector is at ground. The base is about 12v above the negative rail. The emitter is about 11.5v above the negative rail. You can place the black probe on the center leg of the negative rail rectifier adjacent to Q4901 to check these voltages.
The Zener should have 12v when the voltage is measured directly across it. The anode should be directly connected to the negative rail. The cathode is directly connected to the base of Q4901 (3rd leg).
The collector of Q4901 is directly connected to ground (primary and secondary grounds are tied together).
The emitter of Q4901 is directly connected to pin 3 of the IR2010S ICs.
You should read approximately 11.5v between pin 15 (black probe) and pin 3 (red probe) on the IR2010S ICs.The same voltage can be read across C9801 and C9802.
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