Hi all,
I am new to DIY and attempted to "upgrade" a Musical Fidelity V-CANS headphone amp by replacing the caps.
During desoldering, the metal round material around the through-hole was lifted. (not sure what this is called, making searching for it harder. is it the pad?)
The result is that when I tried to solder a new cap, I cannot get a nice concave surface, but only covering half the surface on the pcb hole. I tried it multiple times, and it just seems like there isnt anywhere for the solder to flow to.
What would be the best way to fix this, if possible?
Or is it best not to touch? (the amp is working)
Thanks!
I am new to DIY and attempted to "upgrade" a Musical Fidelity V-CANS headphone amp by replacing the caps.
During desoldering, the metal round material around the through-hole was lifted. (not sure what this is called, making searching for it harder. is it the pad?)
The result is that when I tried to solder a new cap, I cannot get a nice concave surface, but only covering half the surface on the pcb hole. I tried it multiple times, and it just seems like there isnt anywhere for the solder to flow to.
What would be the best way to fix this, if possible?
Or is it best not to touch? (the amp is working)
Thanks!
If half the pad is still there, and is connected to the trace, you should be fine. Reworking PC boards can be tricky, as you've found....
The pad is partially connected to the board, so there is basically half a joint there. It works, but it bothers me that it is not "perfect" :/
Thanks.
Do you have a link to a good guide on how to install them? Should I use the existing hole or do I need a new hole for it ?
Do you mean the via (round tube through the pcb) or the pad ?
If the via is gone you could have problems unless the solder side is only connected to the pad.
If the via is gone you could have problems unless the solder side is only connected to the pad.
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From here that looks like a one sided board. The pad is gone or mostly gone. the trace remains to the next joint. here is my approach. One COULD use tools available to repair the traces and pads, but hardly seems worth the effort many times. SO with the old part out, I would remove all old solder and then on the entire length of that short trace from the red arrow going to the right, I would sand off the green lacquer coating, exposing fresh copper. I'd insert my new cap and solder the left leg to hold it in place. Now the remaining leg is coming up where the pad was. I bend the cap lead wire down flat along the bared trace to the right. And solder it down along that length. Now trim off the remaining wire just before that other joint.
Now the IC on the right side with a bad corner pad. My caps have long lead wires so I can use them as I just described. ICs do not. Their legs poke through the board and not much further. See the trace that first angles a little then goes straight down? I;'d sand off the coating there as well. Then I take a piece of thin bare wire, loop it around the IC pin and tack solder that. Now I lay my thin bare wire down along the bared trace, and sweat solder it there.
An alternative would be to Tack solder a piece of small insulated wire to that IC leg pin. Cut it to length and trim the insulation at the other end, and tack solder it to the component lead joint down at the bottom end of that trace.
As someone mentioned above though, You do need to start by determining if there are solder joints on the other side of the board. If so, you need to accommodate them.
Now the IC on the right side with a bad corner pad. My caps have long lead wires so I can use them as I just described. ICs do not. Their legs poke through the board and not much further. See the trace that first angles a little then goes straight down? I;'d sand off the coating there as well. Then I take a piece of thin bare wire, loop it around the IC pin and tack solder that. Now I lay my thin bare wire down along the bared trace, and sweat solder it there.
An alternative would be to Tack solder a piece of small insulated wire to that IC leg pin. Cut it to length and trim the insulation at the other end, and tack solder it to the component lead joint down at the bottom end of that trace.
As someone mentioned above though, You do need to start by determining if there are solder joints on the other side of the board. If so, you need to accommodate them.
you can attach a wire link to make up for a lifted of removed pad.
Scrape the epoxy coating off the adjacent trace. 3mm to 4mm along the trace is probably sufficient. Try not to damage the copper under the epoxy coating.
Pre-solder that copper trace.
Wrap a single turn of 0.2mm to 0.4mm plain copper wire around the projecting leg of the component and lay the straight wire along the pre-tinned trace. Solder the wire to the trace. Solder the turn to the leg. job done.
You can get thin copper strands from a short piece of scrap stranded cable. 0.15mm, 0.2mm & 0.3mm are common strand diameters in 0.5sqmm, 0.75sqmm and 1sqmm stranded cable.
Scrape the epoxy coating off the adjacent trace. 3mm to 4mm along the trace is probably sufficient. Try not to damage the copper under the epoxy coating.
Pre-solder that copper trace.
Wrap a single turn of 0.2mm to 0.4mm plain copper wire around the projecting leg of the component and lay the straight wire along the pre-tinned trace. Solder the wire to the trace. Solder the turn to the leg. job done.
You can get thin copper strands from a short piece of scrap stranded cable. 0.15mm, 0.2mm & 0.3mm are common strand diameters in 0.5sqmm, 0.75sqmm and 1sqmm stranded cable.
Learn the proper techniques next time, if had been a multi layer board you may have had to scrap it...
Look up PCB rework should give plenty of links.
Best bet cut the component of the board so you only have to de-solder the legs.
Look up PCB rework should give plenty of links.
Best bet cut the component of the board so you only have to de-solder the legs.
Wow thanks for the additional tips here.
I didn't realise the thread went on after the initial responses.
I will definitely follow up on the links here... for my next project
I didn't realise the thread went on after the initial responses.
I will definitely follow up on the links here... for my next project
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