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Post by darkarn on Sept 29, 2020 8:42:04 GMT
Contact Jeremy for the ordernumber of the volpot. Repairing traces can be done by scrathing away the plack lacker at the point where it is still good scratch it till copper is clearly visible. Tin that part carefully. Then run a thin wire from there to the volpot. You can use one strand from a mains cable for instance. Should you want to fix it neatly you can clean the PCB at that point and use a permanent black marker to make it black again. Thank you, I am arranging with Jeremy now for the volpot
For reference, these two points are where the pads got lifted, and I can't see where they lead to. Jeremy advised me that I can just wire them to the grounding wire of the volpot, so which traces do I need to scratch away (if I need to)?
Is it possible for me to glue copper washers or eyelets onto the two spots first before I resolder the new volpot?
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Post by darkarn on Sept 29, 2020 15:59:45 GMT
I searched online for similar cases and found this video
Can I do something like this for my case?
I am just not sure of the exact dimensions of the eyelets I need though
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solderdude
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Post by solderdude on Sept 29, 2020 18:06:50 GMT
These thick PCB's are a real pain to resolder.
Fortunately for you these are the ground pins.
All that has to be done is lay a short wire to the ground plane next to it.
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Post by darkarn on Sept 30, 2020 6:12:43 GMT
These thick PCB's are a real pain to resolder. Fortunately for you these are the ground pins. All that has to be done is lay a short wire to the ground plane next to it.
I was actually quite shocked at the lifted pads; I thought the thickness and build quality of the PCB would help prevent that Sounds like things will get erm, interesting should I manage to find the eyelets for this PCB
I'll solder the ground pins to the grounding wire of the volpot for now while waiting for the new volpot as per this diagram then.
I think I will reflow some of the solder joints too as I think some of them have gone cold and some of them may have been using mixed solder (I thought the solder I was using was the original Kester that was supplied with the kit, turns out to be generic solder. Gotta remember to label my stuff carefully)
Should I also pre-emptively change the capacitors too when I solder the new volpot? This Project Ember has been with me for about 3 years with near-daily usage in a humid environment (it's something to do with Singapore's weather)
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Post by darkarn on Oct 1, 2020 9:08:49 GMT
I tried to solder the ground pins to the grounding wire as shown, but apparently it did not work out as some of the solder mask is removed from my earlier attempts, the wire will be in contact with the middle pads. So I removed the wire and reverted back to before.
Strangely, right now if I use a multimeter to do continuity test, the middle pins are in contact with the grounding pins, but somehow both channels can still be heard
This means right now the situation is the same as before (i.e. the noise is still in the left channel if I change volume) but except the PCB looks more messed up now and I don't even know if I can remove this old volpot for the new one  More importantly, this starts to feel demoralising; I thought it would be an easy fix but somehow I just keep messing up with no end in sight. Not even sure what should be my next step at the point. I even wonder if I should quit DIY or something
I calmed down a bit, yeah, guess I am too stubborn to quit on this amp especially since it still works  Still mightily annoyed at myself for screwing up still!
Or maybe it is time for me to get better equipment before I try again? I am starting to get puzzled about the solder suckers to begin with, maybe I should consider a proper electric solder vacuum instead?
What should I do next? |
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Post by solderdude on Oct 3, 2020 7:32:49 GMT
I was actually quite shocked at the lifted pads; I thought the thickness and build quality of the PCB would help prevent that Sounds like things will get erm, interesting should I manage to find the eyelets for this PCB
I'll solder the ground pins to the grounding wire of the volpot for now while waiting for the new volpot as per this diagram then. I think I will reflow some of the solder joints too as I think some of them have gone cold and some of them may have been using mixed solder (I thought the solder I was using was the original Kester that was supplied with the kit, turns out to be generic solder. Gotta remember to label my stuff carefully) Should I also pre-emptively change the capacitors too when I solder the new volpot? This Project Ember has been with me for about 3 years with near-daily usage in a humid environment (it's something to do with Singapore's weather)
The capacitors don't need changing. They should last for at least 10 years. The only solderjoints you may need to reflow are the ones of the tube socket after very long usage. |
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Post by solderdude on Oct 3, 2020 7:47:37 GMT
I tried to solder the ground pins to the grounding wire as shown, but apparently it did not work out as some of the solder mask is removed from my earlier attempts, the wire will be in contact with the middle pads. So I removed the wire and reverted back to before. Strangely, right now if I use a multimeter to do continuity test, the middle pins are in contact with the grounding pins, but somehow both channels can still be heard
This means right now the situation is the same as before (i.e. the noise is still in the left channel if I change volume) but except the PCB looks more messed up now and I don't even know if I can remove this old volpot for the new one More importantly, this starts to feel demoralising; I thought it would be an easy fix but somehow I just keep messing up with no end in sight. Not even sure what should be my next step at the point. I even wonder if I should quit DIY or something
I calmed down a bit, yeah, guess I am too stubborn to quit on this amp especially since it still works Still mightily annoyed at myself for screwing up still! Or maybe it is time for me to get better equipment before I try again? I am starting to get puzzled about the solder suckers to begin with, maybe I should consider a proper electric solder vacuum instead?
What should I do next? Because of the thick PCB removing parts is very difficult. Pads can just as easily be lifted as with normal thickness PCB's. The reason for using the thicker PCB's is so that the PCB doesn't bend when removing and inserting tubes. How to replace the volpots (yes some do become scratchy). Put a big blob of solder on all 6 pads. Heat it with at least 60W iron so all solder is melted. Don't heat it for too long. Gently pull/wiggle on the volpot and it should come out easily. Now you are faced with the PCB holes that need to be empty to insert a new pot. Desolder litz won't work as the PCB is too thick. Just heat a pad and when hot and bubbling use compressed air to blow it out. NOTE be very carefull hot soldersplatters EVERYWHERE !!!! Personally I grab a drill that fits inside the hole and drill it out. Jeremy can tell you which drillbit you would need. The whole bottom planes (and top planes) are grounded so you can just scratch away the lacker next to the ground pins and solder these directly to the ground planes. |
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Post by darkarn on Oct 3, 2020 15:01:39 GMT
I was actually quite shocked at the lifted pads; I thought the thickness and build quality of the PCB would help prevent that Sounds like things will get erm, interesting should I manage to find the eyelets for this PCB
I'll solder the ground pins to the grounding wire of the volpot for now while waiting for the new volpot as per this diagram then. I think I will reflow some of the solder joints too as I think some of them have gone cold and some of them may have been using mixed solder (I thought the solder I was using was the original Kester that was supplied with the kit, turns out to be generic solder. Gotta remember to label my stuff carefully) Should I also pre-emptively change the capacitors too when I solder the new volpot? This Project Ember has been with me for about 3 years with near-daily usage in a humid environment (it's something to do with Singapore's weather)
The capacitors don't need changing. They should last for at least 10 years. The only solderjoints you may need to reflow are the ones of the tube socket after very long usage.
Thank you, I'll just focus on the volpot and tube socket then
I tried to solder the ground pins to the grounding wire as shown, but apparently it did not work out as some of the solder mask is removed from my earlier attempts, the wire will be in contact with the middle pads. So I removed the wire and reverted back to before. Strangely, right now if I use a multimeter to do continuity test, the middle pins are in contact with the grounding pins, but somehow both channels can still be heard
This means right now the situation is the same as before (i.e. the noise is still in the left channel if I change volume) but except the PCB looks more messed up now and I don't even know if I can remove this old volpot for the new one More importantly, this starts to feel demoralising; I thought it would be an easy fix but somehow I just keep messing up with no end in sight. Not even sure what should be my next step at the point. I even wonder if I should quit DIY or something
I calmed down a bit, yeah, guess I am too stubborn to quit on this amp especially since it still works Still mightily annoyed at myself for screwing up still! Or maybe it is time for me to get better equipment before I try again? I am starting to get puzzled about the solder suckers to begin with, maybe I should consider a proper electric solder vacuum instead?
What should I do next? Because of the thick PCB removing parts is very difficult. Pads can just as easily be lifted as with normal thickness PCB's. The reason for using the thicker PCB's is so that the PCB doesn't bend when removing and inserting tubes. How to replace the volpots (yes some do become scratchy). Put a big blob of solder on all 6 pads. Heat it with at least 60W iron so all solder is melted. Don't heat it for too long. Gently pull/wiggle on the volpot and it should come out easily. Now you are faced with the PCB holes that need to be empty to insert a new pot. Desolder litz won't work as the PCB is too thick. Just heat a pad and when hot and bubbling use compressed air to blow it out. NOTE be very carefull hot soldersplatters EVERYWHERE !!!! Personally I grab a drill that fits inside the hole and drill it out. Jeremy can tell you which drillbit you would need. The whole bottom planes (and top planes) are grounded so you can just scratch away the lacker next to the ground pins and solder these directly to the ground planes.
Ah this explains why wicking/litzing didn't work for me, apparently all solder above the surface will be sucked out but solder will still be stuck in the holes
For the last two holes which had their pads lifted, I am not sure where to heat to get the solder to become hot and bubbling. Does this mean that the only way left is to drill them out?
Also, I am quite nervious about the compressed air method as I have seen videos about it and it shows that the solder will be spread out to the PCB. Is there a way to do this method without the solder spreading further into the PCB?
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Post by solderdude on Oct 3, 2020 20:02:48 GMT
Just poor some solder onto the pins.
Once the pot is out there is another way (remove the tube !!) which is to heat the solder (the pad on the topside will still be O.K.
And very quickly tap the board on the table while the solder is still molten.
Watch out for hot splatter !!!!
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Post by darkarn on Oct 6, 2020 8:34:53 GMT
Just poor some solder onto the pins. Once the pot is out there is another way (remove the tube !!) which is to heat the solder (the pad on the topside will still be O.K. And very quickly tap the board on the table while the solder is still molten. Watch out for hot splatter !!!!
Hmm, looks like I need to be very precise if I do this lest I accidentally damage the other components
Give me some time to decide and arrange with Jeremy accordingly. I need to see if it is better for me to send over the amp for the repairs instead (though recent transport/supply chain issues are making me nervous. Also this means I need to borrow an amp to tide me over), or for me to attempt the repair again with the correct parts (especially the new volpots and maybe the eyelets too?) and tools.
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Post by darkarn on Oct 16, 2020 9:06:50 GMT
Right, took me a while but after much more reading up, I have decided to take another shot at repairing this.
When I reread the emails and the posts here, I too am also wondering if some of the joints on the left signal are starting to get cold and thus causing DC leakage that wear out the pot faster than expected.
So here's what I think I'll do:
1. Resolder any solder joints that look cold/dull, especially those regarding the left channel, and use this chance to check if the capacitors are somehow leaking (it is unlikely but good to check)
2. Remove the old volpot
3. Put in the eyelets or at least copper tape or jumper cable, depending on what I can/want to do by then
4. Put in a 6 pin socket, then the new volpot (idea is to make future replacement of the volpot easier since it wears out)
5. Repair the solder mask with UV curable solder mask solution (optional)
This will be an erm, interesting lesson on reworking for me but I guess this is part and parcel of DIY I suppose
May I know which joints are related to the left channel so that I can pay more attention to?
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Post by solderdude on Oct 21, 2020 10:07:59 GMT
Right, took me a while but after much more reading up, I have decided to take another shot at repairing this. When I reread the emails and the posts here, I too am also wondering if some of the joints on the left signal are starting to get cold and thus causing DC leakage that wear out the pot faster than expected. So here's what I think I'll do: 1. Resolder any solder joints that look cold/dull, especially those regarding the left channel, and use this chance to check if the capacitors are somehow leaking (it is unlikely but good to check) 2. Remove the old volpot 3. Put in the eyelets or at least copper tape or jumper cable, depending on what I can/want to do by then 4. Put in a 6 pin socket, then the new volpot (idea is to make future replacement of the volpot easier since it wears out) 5. Repair the solder mask with UV curable solder mask solution (optional) This will be an erm, interesting lesson on reworking for me but I guess this is part and parcel of DIY I suppose May I know which joints are related to the left channel so that I can pay more attention to? There won't be DC leakage near the pot. All signals are next to ground planes. 1: I would reflow/add solder to the tube socket pins and the inductor of the heater voltage regulator. It is highly unlikely others may have failed. Solderrot only happens when solder becomes hot (only the tube socket and inductor becomes warm) or when high currents flow or mechanical stress is present. The latter is only the case for the tube socket. 4: Pins of a potmeter usually don't fit in sockets. besides you would still have to ground the pot and when it is in a socket you would have to mechanically ensure the pot doesn't come loose. 5 The solder mask doesn't have to be repaired. When you want it all black again just use a permanent black marker. |
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Post by darkarn on Oct 21, 2020 11:01:53 GMT
Right, took me a while but after much more reading up, I have decided to take another shot at repairing this. When I reread the emails and the posts here, I too am also wondering if some of the joints on the left signal are starting to get cold and thus causing DC leakage that wear out the pot faster than expected. So here's what I think I'll do: 1. Resolder any solder joints that look cold/dull, especially those regarding the left channel, and use this chance to check if the capacitors are somehow leaking (it is unlikely but good to check) 2. Remove the old volpot 3. Put in the eyelets or at least copper tape or jumper cable, depending on what I can/want to do by then 4. Put in a 6 pin socket, then the new volpot (idea is to make future replacement of the volpot easier since it wears out) 5. Repair the solder mask with UV curable solder mask solution (optional) This will be an erm, interesting lesson on reworking for me but I guess this is part and parcel of DIY I suppose May I know which joints are related to the left channel so that I can pay more attention to? There won't be DC leakage near the pot. All signals are next to ground planes. 1: I would reflow/add solder to the tube socket pins and the inductor of the heater voltage regulator. It is highly unlikely others may have failed. Solderrot only happens when solder becomes hot (only the tube socket and inductor becomes warm) or when high currents flow or mechanical stress is present. The latter is only the case for the tube socket. 4: Pins of a potmeter usually don't fit in sockets. besides you would still have to ground the pot and when it is in a socket you would have to mechanically ensure the pot doesn't come loose. 5 The solder mask doesn't have to be repaired. When you want it all black again just use a permanent black marker.
Thank you, I'll stick with at least soldering the new volpot when it reaches me.
Meanwhile, is permanent black marker conductive (or rather, not insulative enough)? I noticed that even after "coloring" over the exposed copper traces, it would still be considered conductive when doing a continuity test with a multimeter
Also, how much current is high enough for solder-rot to happen?
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Post by solderdude on Oct 23, 2020 16:06:52 GMT
Thank you, I'll stick with at least soldering the new volpot when it reaches me.
Meanwhile, is permanent black marker conductive (or rather, not insulative enough)? I noticed that even after "coloring" over the exposed copper traces, it would still be considered conductive when doing a continuity test with a multimeter Also, how much current is high enough for solder-rot to happen?
I have not noticed a marker would be conductive. Maybe marker dependent. When it is fully dry there probably aren't conductive materials in there. Alternative: black paint (hobby paint, small pots for model airplanes) or black nailpolish (will probably exist) Nor does it matter because the 2 damaged pads are the same ground as what surrounds it. For solderrot you need high temp, and movement (for instance a heatsink expanding at higher temp) The currents are mA's |
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Post by darkarn on Oct 23, 2020 22:25:36 GMT
Thank you, I'll stick with at least soldering the new volpot when it reaches me.
Meanwhile, is permanent black marker conductive (or rather, not insulative enough)? I noticed that even after "coloring" over the exposed copper traces, it would still be considered conductive when doing a continuity test with a multimeter Also, how much current is high enough for solder-rot to happen?
I have not noticed a marker would be conductive. Maybe marker dependent. When it is fully dry there probably aren't conductive materials in there. Alternative: black paint (hobby paint, small pots for model airplanes) or black nailpolish (will probably exist) Nor does it matter because the 2 damaged pads are the same ground as what surrounds it. For solderrot you need high temp, and movement (for instance a heatsink expanding at higher temp) The currents are mA's
Actually the marker/paint is more for covering the exposed copper track elsewhere. I'll look for those (at least a different brand of marker) once I am done with the volpot replacement
Thanks about the solderrot info by the way, it is my first time hearing about this. Does this happen to leaded solder more than non-leaded (RoHS) solder?
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Still mightily annoyed at myself for screwing up still!