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PostPosted: Sun Apr 21, 2013 3:31 pm 
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Here are the finished pics of my plexi ll build. It started out as the standard plexi, then I decided to switch it over to the brown mod. I redid the board, and now I'm barely getting any output. There is output on both channels but the volume is very very low. I will post my voltages in a second post. Any suggestions would be great.
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PostPosted: Sun Apr 21, 2013 8:21 pm 
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Here are my voltages

V1
Pin 1-158
pin 3-1.0
pin 6-164
pin 8-1.0

V2
pin 1-154
pin 3-1.0
Pin 6-284
pin 8-155

V3
pin 1-294
pin 2-48.1
pin 3-51.3
pin 6-208
pin 7-48
pin 8-51.3
the power tubes and rectifier are right on voltage wise. V3 looks way off to me, and the tube itself is getting warm to touch, but not hot. I have tried swapping different tubes and that didn't change anything. I can post more pics also if needed. Thanks in advance for any help.
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PostPosted: Sun Apr 21, 2013 11:12 pm 
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Nothing obvious pops out.

V3 voltages don't look terrible. Did you try swapping tubes there and remeasuring the voltages?

I'd be looking for incorrect wiring somewhere near the PI/output section.

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PostPosted: Mon Apr 22, 2013 6:47 pm 
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Thanks so much for the help. After completely rewiring it 2 times, I found out the tube socket on V3 is bad. Gonna get a new one tomorrow and fire it up. Thanks again


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PostPosted: Tue Apr 23, 2013 7:20 pm 
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Just curious, what was wrong with the tube socket?

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PostPosted: Wed Apr 24, 2013 4:33 pm 
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Hi Stephen,
It was fine initially. Just me going in there to many times with the soldering iron, and not being very careful. After I fired it up the last time, I was still getting high voltages on the PI, and the tube wasn't getting very hot. I thought maybe I had a cold solder joint on the heaters, so I redid those and still the same thing, barely any output, and a cool tube, with hum. I switched out three or four different tubes, then I physically moved the PI tube around in the tube socket and it would quite humming. I would also get normal output, and normal voltages. If I positioned the tube just right in the socket it would work fine, and if I moved it around I could get it to go back to the original problem. Long story short, I probably burned up the socket going in and out of the amp to many times. Do you agree, or do you think it could be something else?


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PostPosted: Wed Apr 24, 2013 5:13 pm 
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I think its more likely one of the connections on the tube socket was bad.

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PostPosted: Thu Apr 25, 2013 8:31 am 
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Normally id say connection, but there is something going on there when you move the tube. Probably best to rewire. But confirm the tube is good.
Maybe desolder and redo the socked one last time.

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PostPosted: Thu Apr 25, 2013 3:55 pm 
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Hey, just an update. The amp is up and running great. Haven't had a chance to play with it too much yet, but all is well. The tube socket was indeed bad, it had a cracked lug on it, probably from me soldering and resoldering. Thanks to all for all the help, it was a great learning experience. Now I'm just waiting on my VRM so I can keep the wife happy :)


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