OK, I've noticed that there's a little solder pad next to the R48 resistor on the coaxial input trace, which might correspond to the notation "open" to one side of it in the circuit diagram (see previous post). How would I make R48 open; solder a wire from that pad to ground?
I've also noticed that the same notation of "open" appears at Port 2, which accepts a 10-pin external USB input adapter that's listed as one of the input types in the manual (it came with the board). Each of those connections likewise has the "open" notation and a little solder pad next to it, with instructions in the manual for which ones should be "open" and "closed" for that input type. I guess if I solder the right connections on those pads, I should be able to use digital audio data from a laptop (i.e. streaming Tidal) as music input, correct?
So, how do I make those connections?
Again, please forgive these extremely basic questions. I really don't have much experience manipulating PCBs; it's kind of a different language from from the other side of my DIY audio life.
I've also noticed that the same notation of "open" appears at Port 2, which accepts a 10-pin external USB input adapter that's listed as one of the input types in the manual (it came with the board). Each of those connections likewise has the "open" notation and a little solder pad next to it, with instructions in the manual for which ones should be "open" and "closed" for that input type. I guess if I solder the right connections on those pads, I should be able to use digital audio data from a laptop (i.e. streaming Tidal) as music input, correct?
So, how do I make those connections?
Again, please forgive these extremely basic questions. I really don't have much experience manipulating PCBs; it's kind of a different language from from the other side of my DIY audio life.
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You don't have to remove R48. You can just put a solder blob on R46 and if it works then you can switch the resistors.
Port2 is for I2S input. To use it you should switch resistors R30->R29,R32->R31 and so on.
Port2 is for I2S input. To use it you should switch resistors R30->R29,R32->R31 and so on.
I'm assuming you meant to connect the two metal squares under R46 with solder. I couldn't get solder to span the gap, so I used a thin lead from a small resistor and then cut the excess. Still no sound.
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Ok, remove R48 just to be sure. Then you could measure if there is any AC voltage on R46 when you play a CD.
If by DVM you mean digital voltage meter, then yes: I have a digital multimeter.
I've not removed anything, so R45 and R48 are still there. I've never removed these types of resistors before. Have only worked with the through-hole kind.
I've not removed anything, so R45 and R48 are still there. I've never removed these types of resistors before. Have only worked with the through-hole kind.
Okay, what soldering equipment do you have? Temp controlled iron? Set of various tips? Extra paste or liquid flux? Small diameter low temp solder wire? Solder-wick, small size? Tip cleaner?
Do you have fine tip tweezers? (e.g. https://www.amazon.com/Aven-18072EZ-Precision-Tweezer-Stainless/dp/B006RBANAS )
A better type for electronics is non magnetic: https://www.amazon.com/Aven-18072TT...x=aven+style+7+titanium,industrial,127&sr=1-1
Do you need a magnifier to see what you are doing?
Do you have a good way to hold the PCB steady while you work?
Do you have fine tip tweezers? (e.g. https://www.amazon.com/Aven-18072EZ-Precision-Tweezer-Stainless/dp/B006RBANAS )
A better type for electronics is non magnetic: https://www.amazon.com/Aven-18072TT...x=aven+style+7+titanium,industrial,127&sr=1-1
Do you need a magnifier to see what you are doing?
Do you have a good way to hold the PCB steady while you work?
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Regarding the DVM, you might see if you can ring out the connection you soldered. Did it successfully jumper R46, without shorting anything to ground?
Okay. To remove a resistor select a tip as wide as the resistor is long. You will heat both ends at once from the side. You may need to add some extra solder to one or both ends to help conduct the heat. Eventually the resistor will pop loose. Extra flux is often helpful when soldering miniature parts. Keeps solder wetting more effective and helps control solder surface tension.
Alternatively, its possible to quickly heat one end of the resistor then the other, back and forth, until both ends are melted at once. Adding extra solder to the ends may help retain heat while the other side is being heated.
When the resistor pops loose it may fly away or it may stick to the tip of the iron. In the latter case, you could try removing it with a tip cleaner or maybe try tapping the barrel of the iron on the bench to shake the resistor loose. Wear eye protection of course.
All that's left is to clean up the pads with solder wick and maybe some extra flux.
Alternatively, its possible to quickly heat one end of the resistor then the other, back and forth, until both ends are melted at once. Adding extra solder to the ends may help retain heat while the other side is being heated.
When the resistor pops loose it may fly away or it may stick to the tip of the iron. In the latter case, you could try removing it with a tip cleaner or maybe try tapping the barrel of the iron on the bench to shake the resistor loose. Wear eye protection of course.
All that's left is to clean up the pads with solder wick and maybe some extra flux.
It sure looks like R45 was removed. Check the resistance from R46 to Optical Out pin which is just next to R45. The resistance should be 51ohms.
It measures like 28.5M. I checked the sponge I wiped off the tip into, and there appears to be something foreign in one of the solder drippings. I bet that's it.
I wonder if I can just solder a jumper at R45? 51 ohm is not much.
Also, was the schematic saying to shift the resistor from the pads at R48 to the pads at R46?
I wonder if I can just solder a jumper at R45? 51 ohm is not much.
Also, was the schematic saying to shift the resistor from the pads at R48 to the pads at R46?
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Well, a scope probably the best tool for the troubleshooting job if ringing out with a DVM doesn't work. Maybe its time to start learning the scope?
Regarding R45, it should be somewhere around 50-ohms to damp out ringing of the square waves. You can tack a small 1/8 watt leaded resistor onto the pads. Or else find the smallest 50-ohm resistor can find and if you can't tack its leads to the pads, maybe you could use some VERY short pigtail leads made from a single strand of stranded wire. Small and short are key since this is RF. Long leads on a resistor make an antenna and my cause other problems.
Regarding R45, it should be somewhere around 50-ohms to damp out ringing of the square waves. You can tack a small 1/8 watt leaded resistor onto the pads. Or else find the smallest 50-ohm resistor can find and if you can't tack its leads to the pads, maybe you could use some VERY short pigtail leads made from a single strand of stranded wire. Small and short are key since this is RF. Long leads on a resistor make an antenna and my cause other problems.
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