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Old 6th April 2011, 02:04 AM   #11
tomchr is offline tomchr  United States
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Or get a flux pen. Apply fresh flux to the pad, heat it up, and apply new solder.
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Old 6th April 2011, 02:17 AM   #12
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I've got to ask how the board got into such a condition in the first place. Is the soldering iron too hot or too cold? If the iron is not temperature controlled, is the wattage at least appropriate for this kind of work? Is the tip poorly tinned or in otherwise poor condition? Would it be worthwhile to spend a little time practicing on a junk circuit board, and try putting random things on and taking them off again?
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Old 6th April 2011, 02:51 AM   #13
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A little tip George(tubelab) gave me on how to remedy a lifted solder pad....worked like a charm.
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I have a few lifted pads on my board since some components have been changed several times. Many of the component holes on this board are used to make a connection from the top to the bottom of the board. Often that connection gets broken when a pad is lifted. In this case it may be necessary to solder tha component on both sides of the board. Of course it is impossible to solder the leads on the top side of the board on some components like C27. In this case I scrape some resist off of the runner on the top side, solder a thin bare wire (one strand from line cord or speaker wire) to the bare copper, run the wire through the component hole, insert the component, then solder the component and the wire to the remaining trace on the bottom side. Verify continuity before powering up the board.
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Old 6th April 2011, 06:11 AM   #14
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I did use solder with flux(WBT leaded). I used adjustable heat soldering station with new tips since I just bought the whole thing. Temp was set at recommended 600F and all other resistors soldered well within 5-7 seconds. With R3 the I needed to desolder it and I did that with braid(newly bought containing flux), but I spent too much time make sure pads are residue free. Pads look ok now but the solder is not melting on pads.

I'll find some 91% isopropyl from drugstore..will that be ok or you guys recommend some other alcohol? if so where to get it?

Last edited by imnewbie; 6th April 2011 at 06:40 AM.
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Old 6th April 2011, 12:44 PM   #15
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Quote:
Originally Posted by imnewbie View Post
I did use solder with flux(WBT leaded). I used adjustable heat soldering station with new tips since I just bought the whole thing. Temp was set at recommended 600F and all other resistors soldered well within 5-7 seconds.
That all sounds well and good.

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With R3 the I needed to desolder it and I did that with braid(newly bought containing flux), but I spent too much time make sure pads are residue free. Pads look ok now but the solder is not melting on pads.
Is it possible you actually removed the whole pad from the board? Try setting your multimeter to test for continuity, and touch the probes across the problem pad and the C3 hole.

Is this the end of R3 that lands on the big common ground plane? If so, maybe you could solder the resistor from the top side. Otherwise you could just stick the tail of the resistor through the hole and bend it over to C3. If you haven't already trimmed C3, you can even twist the ends together a bit.

Last edited by Ty_Bower; 6th April 2011 at 12:52 PM.
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Old 1st May 2011, 11:59 PM   #16
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Default 12AT7 not glowing

So I connected R3 with C3 by bending tail of C3 with R3 tail. Today I finished the PCB and since my order from Edcor arrived I decided to turn it on today.

There was no music and the 12AT7 was not glowing but all other tubes including 5AR4 were glowing. I used another 12AT7 and a 12AU7 in but none of them glowed. The both Ruby 6L6GC glowed but both of their inside bottom plates had a tiny bit blue shine. I'm using 820 ohm bias resistor and an Edcor XPWR035. I checked and double checked PT and OPT wiring. The PCB was double checked every time after each part was soldered on.

My Edcor XPWR035 has 3.15v/3.15v secondary wires coming out with 120v/120v primaries, while their picture and schematic on webpage have all secondary wires coming out from one side and two 120v wires from another side of transformer. I don't know if this is their mistake and causing the problem.

http://www.edcorusa.com/products/628-xpwr035_120.aspx

Please help!

Last edited by imnewbie; 2nd May 2011 at 12:14 AM.
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Old 2nd May 2011, 02:11 AM   #17
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Quote:
Originally Posted by imnewbie View Post
There was no music and the 12AT7 was not glowing...
The 12AT7 should be glowing at each of the cathodes, from its heaters. If you can't see a orange glow at each heater, you will get no music. Can you pull the tube and check for 6.3V heater voltage at pins 4 and 5? It would be safest to keep the rectifier tube out while performing this check.

http://i69.photobucket.com/albums/i4...out/volt01.jpg
http://i69.photobucket.com/albums/i4...out/volt02.jpg
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Old 2nd May 2011, 03:09 AM   #18
rknize is offline rknize  United States
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If the 6L6s are glowing but the 12AT7 is not, then it is most likely a bad solder joint or broken trace at the socket. Could also be a broken pin on the socket.
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Old 2nd May 2011, 07:37 PM   #19
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Ty, the measurement at pins 4 and 5 reads 3.4v. I took out 5AR4 as you said but the 6l6s were in and OPTs were connected to PCB too. I never used multimeter before so correct me if the method I used is wrong because the ground lead was pinned to one the grounds on the PCB(as shown on tubelab's "wiring diagrams" page.
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Old 3rd May 2011, 07:12 AM   #20
rknize is offline rknize  United States
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Are you using the AC volts setting on your meter? Also, pins 4 and 5 should be tied together, so you should read no voltage there. You should measure 6.3V between pin 4 or 5 and pin 9.
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