A12 U1 polarity

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A12 U1 polarity

Postby derxbrax » Fri Oct 15, 2010 9:12 pm

When checking voltage at U1 pin 3, I recieve a -14v, and pin 5 shows -9.8v.

I have checked over all the diodes and capacitors, and everything seems to be correct. Also I will mention I have the transformer upgrade to high nickel if that makes a difference.

If anyone has any suggestions, I would be very grateful!
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Postby tpryan » Mon Oct 18, 2010 7:09 am

What voltage do you measure at the anode of D3?
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Postby derxbrax » Mon Oct 18, 2010 6:23 pm

think I may have located the problem. When looking over my capacitors, I realized my C13 capacitor casing twists free from the base. Just put in a part order from digikey to see if that takes care of it. Ill post my results on that. Thanks for the response.
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Postby derxbrax » Sat Nov 06, 2010 8:20 pm

I replaced the capacitor, but my problem with voltage remains. The voltage measured at D3 is -29.4V. Please let me know if you have any thoughts. Thanks again
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Postby tpryan » Wed Nov 10, 2010 10:32 am

What voltage do you measure at the negative terminal of C13?

What voltage do you measure at the positive terminal of C10?
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Postby derxbrax » Tue Nov 16, 2010 4:27 pm

Sorry for the delayed response. The voltage I measured at the negative pin of C13 is -29.2V. The positive pin of C10 is 29.2V. Thanks again for your responses.
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Postby tpryan » Mon Nov 22, 2010 11:57 am

What voltage do you measure at the cathode (striped end) of D5?

What voltage do you measure at the anode of D7?
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Postby derxbrax » Wed Nov 24, 2010 4:20 pm

the voltage at the cathode of D5 is 28.5V. The voltage at the anode of D7 is -14.6V.
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Postby tpryan » Fri Nov 26, 2010 4:38 pm

It should be clear to you from the schematic that the cathode of D5 should be the same voltage as U1, pin 3. First you measure -14V and then 28.5V? I suggest you get some advice from a local tech or send an e-mail to rma@seventhcircleaudio.com for return instructions.
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