Solder Both Sides of PCB?

[cudbucket]

I noticed while working on my JCM 2000 DSL that you can see a little solder on the top side (component) of the board. But when I changed my grid and bias resistors, little if any made it through the hole from the leg side. Continuity is good on everything though. Do you have to apply some solder from the top as well? Seems like it would be super difficult. If so, how do you do that for upright caps? Should I be worrying about this at all?

Dave

[g1]

Should not matter. If it's double sided board, there are "vias" connecting top to bottom traces. They are like little copper pipes that the component legs go through.
If you have double sided board and the via gets ripped out, then you have to solder both sides or reconnect top to bottom trace somehow.

[cudbucket]

Thanks G1. I noticed that. When I removed R71 to install a choke, I drilled out the holes to accept turrets. I believe I removed those vias in doing so. But there is no trace on top of the board at this location. Only below where I soldered the turrets in. I have continuity so in this case, I think I'm good.

Thanks for the reply.

Dave

[Jazz P Bass]

The double sided boards are great when you have an unusual number of traces to layout.

Can't make it?
Run up through the via & off you go.

The double clading also helps to secure heavier components .
IF the solder goes to both sides.

I have seen cracked pads and cracked vias all because either the through hole was to small, thus the solder doesn't wick up, or lack of QC at the wave solder station.
I think the oldest trick to increase production is to cut back on the preheat time.
And you end up with solder that doesn't wick properly.

Meniscus is the term.

Here is a nice tutorial on proper soldering tecnique.

http://training.ipc.org/demos/pdf/drm-pth-d.pdf

[Steve A.]

The best advice I read about using a cheap soldering iron was in one of Craig Anderton's books, I think: plug it in and go get a cup of coffee. Back then my big problem was cold solder joints...

If the back side of the PCB is mainly a ground plane one purpose of the little donuts on the back is to help hold the component in place so as to not lift up on the trace topside. If you manage to screw up both the via and the donut you can help secure the component by bending the lead a little bit and back, avoiding the ground plane unless that is the intended destination. And its a good idea to take a digital picture of the traces in case they get damaged and you need to reconstruct them later. (This advice is for people experimenting with different components, soldering and removing them repeatedly.)

Steve A.

[cudbucket]

Thanks for the replies gents.

Dave

[olddawg]

Lately... The most problems I have seen recently with double sided boards are in powered speakers, specifically in stress points caused by large components such as filter caps. Many times in replacing them I have to set the replacement cap up a bit "on its legs" so I can get the tip of a soldering iron under it. Worse case I have had to run a fly wire around the board. I was trained to desoldering and clean boards, then use liquid flux to make the new solder flow through these "vias" when heat is appropriately applied. But it doesn't always work. The best advice is to take your time and think about what you are doing. Every situation is different. With double sided boards it is nearly always preferable to cut the leads off of a component then remove the leads gently, with an iron, one at a time.

[Steve A.]

The best advice is to take your time and think about what you are doing. Every situation is different. With double sided boards it is nearly always preferable to cut the leads off of a component then remove the leads gently, with an iron, one at a time.

Agreed! It brings to mind the statement in R.G.'s troubleshooting guide for tube amps that it is better to sacrifice a 5 cent component by cutting the leads (or cutting it in half) than ruin a $100 PCB that is probably not even available anymore. Been there, done that...

Steve Ahola

P.S. When I was working at the Pacific Stereo central parts dept back in the 70s one of the techs ordered a PCB for a Sony receiver, presumably because he could not figure out what was wrong with it. He was very disappointed when he received the PCB unstuffed, as I recall the only way that Sony would supply the board. Yes, they expected the service tech to remove and install every component on the board.

[olddawg]

Agreed! It brings to mind the statement in R.G.'s troubleshooting guide for tube amps that it is better to sacrifice a 5 cent component by cutting the leads (or cutting it in half) than ruin a $100 PCB that is probably not even available anymore. Been there, done that...

Steve Ahola

P.S. When I was working at the Pacific Stereo central parts dept back in the 70s one of the techs ordered a PCB for a Sony receiver, presumably because he could not figure out what was wrong with it. He was very disappointed when he received the PCB unstuffed, as I recall the only way that Sony would supply the board. Yes, they expected the service tech to remove and install every component on the board.

That board thing happened all of the time. Lol. The part number was for the board. Every component had its own part number. You could occasionally get a board but you had to request it through a manufacturer tech rep. If they didn't know you well, more than likely you would be required to send it in for evaluation and you better hope the tech didn't overlook some simple problem. You worked for Pacific Stereo? I was the head tech for DOW in the 70s! Authorized for everything from Akai to Zenith. Yamaha was a bitch. You had to actually take a bunch of competency tests.