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Old 20th January 2012, 01:41 AM   #41
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I measured the top of U5 pin, the one closest to the power adapter jack and it got .002. That was with the black to the ground on the source input and the red to the pin on the U5. That means that is the pin that needs the 20 volts I was getting with the D3 band right? WHAT CAN I DO! Doesn't this mean the U5 is a bad batch or what?
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Old 20th January 2012, 01:47 AM   #42
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Oh that could be in, the top of the D3 where it's banded is pretty much not covered with solder. But none of them are like the D2 or whatever as well has the same thing. Do I need to do it for all of them? I thought you just soldered the bottom?
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Old 20th January 2012, 01:56 AM   #43
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Just filled in the holes on each of the D series of things and it didn't help anything. Darn! You mean the hole that the pin on the banded D3 goes into is square right and solder that so that it is closed instead of open right? It didn't do anything! I'm telling you, there is no trace that goes from the D3 to any of the U5 pins. There is nothing that connects the D3 to U5 in regards to the lighter colored green line inside the board trace if that is what you mean. Can I try connecting the banded end of D3 to a pin on the U5 via a hookup wire?
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Old 20th January 2012, 01:56 AM   #44
agdr is offline agdr  United States
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Quote:
Originally Posted by jschristian44 View Post
I measured the top of U5 pin, the one closest to the power adapter jack and it got .002. That was with the black to the ground on the source input and the red to the pin on the U5. That means that is the pin that needs the 20 volts I was getting with the D3 band right? WHAT CAN I DO! Doesn't this mean the U5 is a bad batch or what?
So yes, if you are measuring .002 ohms between ground (black lead on the gain switch shell) and the pin of U5 closest to the on/off switch (red lead there), then that isn't right. That would say there is a short to ground on that trace. HOWEVER - are you sure that you have your meter on resistance and not voltage, and that the O2 is unplugged from the power adaptor? Usually the resistance of the test lead themselves, if you just connect the tips together, are around 0.1 ohms.

The next step would be to find what is shorted to ground by unsoldering parts one by one. There are just 4 things on that trace that connects the banded end of D3 and the top pin of U5: U5, D3, C2 and C4. Since you have already replaced U5 you probably should start by pulling out the capacitors. For what it is worth, I personally have had a bad C2 right out of the bag from Mouser. The vents on the top were split open and brown electrolyte was coming out. I never applied power to it since I saw it while assembling an O2, so I don't know if it was shorted or not. But it is entirely possible for electrolytic capacitors to be shorted.

So... unsolder those 4 parts one at a time and after each make another resistance reading from that trace connecting to the top pin of U5 to ground and find out which part is shorted. Also be sure to solder that square via hole as I posted above. That could explain how you were able to get +19V on the banded end of D3 while the top pin of U5 was shorted to ground at the same time. Normally you can't have both. But if the via hole were broken it would break the trace.

I'm going to have to bag it for the evening and probably won't be able to log on during the day tomorrow, so the other folks in the forum here can help you further. Good luck!

Last edited by agdr; 20th January 2012 at 02:04 AM.
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Old 20th January 2012, 02:02 AM   #45
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So I should unsolder one by one and whenever the U5 pin reads the right voltage, I know it's a bad capacitor that I just removed right?
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Old 20th January 2012, 03:09 PM   #46
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Hey agdr,
I removed both C2 and C4 and they were fine. I can't really remove D3 or U5 so I just left them be. They both look brand new and in awesome shape. As do the tracks. The funny thing is, I replaced C2 and C4 again and then I measured the top pin of U5 and I actually got the same reading now as the banded end of D3. But I went to plug it in and I STILL do not get power. I was so confident it would work since I got voltage there at 19 or whatever the D3 had and I figured that was the problem, but now it still doesn't work. This has to be something wrong with the board now right because the parts should work fine?
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Old 21st January 2012, 12:49 PM   #47
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Hey,
After all those stupid tests I figured it out. NwAVGuy told me to test my Power Adapter and I found out it was a dud. I tried my other one and it worked perfect. I am suprised no one told me to do that from the start. What a relief, they both work perfect now.
Justin
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Old 21st January 2012, 02:44 PM   #48
agdr is offline agdr  United States
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Quote:
Originally Posted by jschristian44 View Post
Hey,
After all those stupid tests I figured it out. NwAVGuy told me to test my Power Adapter and I found out it was a dud. I tried my other one and it worked perfect. I am suprised no one told me to do that from the start. What a relief, they both work perfect now.
Justin
Actually someone did, back in post #21:

Quote:
Originally Posted by agdr View Post
First off, measure the output of your AC adapter with it unplugged from the O2. Put your meter on 20V AC (upper right part of the dial, make sure it is not the DC setting in the upper left dial) setting and measure what is coming out of the adapter. Make sure the adaptor is plugged into the wall, of course. If your adaptor has different voltage settings like raspunsen's did, use the "16VAC" setting. If your meter doesn't give a result try the next highest 200V AC range. Your adapter may be putting out more than 20V AC.
I don't recall you mentioning that you were going back and forth between two different power adaptors. That explains how you measured the correct voltage on D3 at one point.

Glad you got it working! I'm sure you have learned a bit about electronics along the way, too, which is always good.

Last edited by agdr; 21st January 2012 at 02:49 PM.
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Old 21st January 2012, 03:17 PM   #49
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I have learned a ton so far. But the only thing is, I was only using this Power Adapter the whole time. It is a beefed up one, but I never knew how to take measurements of the power. I thought putting the probe inside the end would electricute me.
Justin
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Old 21st January 2012, 05:53 PM   #50
agdr is offline agdr  United States
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jschristian44 - good point! I could see how someone who hasn't worked with all this stuff before would be concerned about that, since the adapter is plugging right into the wall socket.

There is a transformer inside of those, essentially just two coils of wire that are insulated from each other, that separates the wall socket side from the "user" side with the lower voltage. You are always OK touching the "outer" metal part of the output plug barrel. But as for also touching that "inner" terminal on the plug, which would complete the circuit, it is still good to be cautious when measuring the output of adaptors with higher voltages - 20V and above - especially if they output DC (the O2 adapter output AC). Just use the meter probes to touch the inner terminal and keep the fingers away.

Congratulations again on your working O2!

Last edited by agdr; 21st January 2012 at 05:56 PM.
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