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Old 16th June 2011, 08:19 PM   #11
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Pin 1: 3.50
Pin 2: 0
Pin 3: 3.50
Pin 4: 3.50
Pin 5: 0
Pin 6: 3.50
Pin 7: 0
Pin 8: 3.42
Pin 9: 3.05
Pin 10: 3.44
Pin 11: 3.40
Pin 12: 0
Pin 13: 3.40
Pin 14:3.38
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Old 16th June 2011, 08:23 PM   #12
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See if the voltages are different on the inductors and the IC If you use the secondary CT as the reference (black probe).
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Old 16th June 2011, 08:34 PM   #13
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i must be stupid today do u know which one is the secondary center tap on the transformer?
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Old 16th June 2011, 08:46 PM   #14
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They are where the two center wires on the power transformer that go into the board near the yellow cored inductor.

I think you'll find that everything reads 0v. If that's the case, you'll have to remove the transistor that's driving pin 4 high, clamp all transistors tightly to the heatsink and power the amp up via a 15 amp fuse or a current limiter. There is some risk that the outputs will be damaged (I'm assuming that you've checked the outputs and none are defective as of now) but you need to get the amp to power up to find what's causing the fault.
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Old 16th June 2011, 09:19 PM   #15
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if i remove the transistor that connects to pin 4 the amp wont power up and the protection light goes off..

Pin 4 of the 494 the voltages pulse's up and down with the transistor removed
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Old 16th June 2011, 09:21 PM   #16
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Does the power supply stay on long enough (between pulses) to have a steady regulated voltage on the op-amps?
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Old 16th June 2011, 09:24 PM   #17
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Ok i had the wrong transistor Pulled an A1266 (Q13) amp powers up and relays kick on. Amp idles perfectly
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Old 16th June 2011, 09:25 PM   #18
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Does it produce clean audio?
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Old 16th June 2011, 09:45 PM   #19
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Yes
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Old 16th June 2011, 10:35 PM   #20
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If it has 2 op-amps near the power supply IC, post the DC voltage on all of the pins of each one.
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