Pcb repair

[AUDIO FREQ]

I got this old board I used as a donor/experimentation learning tool. I’d like to now turn it into something.

Any good ways to fill in the pcb? Epoxy? Resin? I’ve always wandered how these things are repaired professionally. But any suggestions would be great!

 

[ccaudle]

I’ve always wandered how these things are repaired professionally.

You don't repair that kind of damage professionally, you either replace the assembly, or you just add wires and bypass the PCB traces.

Was this from a torch? Because if it wasn't something with a flame your iron is way too hot.

 

[AUDIO FREQ]

You don't repair that kind of damage professionally, you either replace the assembly, or you just add wires and bypass the PCB traces.

Was this from a torch? Because if it wasn't something with a flame your iron is way too hot.

View attachment 109874

No, that's actually cw2500 top coating. It looks like that because the stuff hardens and looks lumpy and dark. I am going to remove it and do as you say, bypass the pcb traces and maybe layer a small cutout of custom made pcb on top of it.

P.s. what setting do you use your iron? Mine is on 400 celsius and I use one of those pine solder pencils. Is that too hot?

 

[industrialarts]

My $0.02

I think that 400C is a bit high. I have a T12 station (that I love!) and I set it for 360C which seems to work in most situations. However, it has the ability to boost an additional temperature for a pre-set time, mine is +40C, so I use 400C for difficult joints. Mostly runs at 360, I found that as the suggested temp for general soldering from research I did a while ago and it seems like solid advice.

 

[AUDIO FREQ]

My $0.02

I think that 400C is a bit high. I have a T12 station (that I love!) and I set it for 360C which seems to work in most situations. However, it has the ability to boost an additional temperature for a pre-set time, mine is +40C, so I use 400C for difficult joints. Mostly runs at 360, I found that as the suggested temp for general soldering from research I did a while ago and it seems like solid advice.

I will try 360. Idk why but I always sat the iron at the highest it goes. Maybe thats why my tips always break after a few months.

 

[ccaudle]

what setting do you use your iron?

I use a Metcal soldering station, it does not have settable temperature, the tip design sets the temperature. There are different temperature ranges available, but I got mine before lead-free took over, so I think it is the lower range, something like 330C or 350C. I can double check later to verify.
It is something like this though:
Metcal STTC-004 tip

 

[JMan]

I keep mine set at around 650 Fahrenheit, which I think is just a bit lower than what @industrialarts suggested above, and it works for me 99% of the time. I'd say anywhere in this 350-ish Celsius range will serve you well.

 

[ccaudle]

I just verified my Metcalf tips. Small and medium are 330C, my largest (2.5mm chisel) is 390C.

 

[AUDIO FREQ]

Thanks guys. I think you guys may have saved my future tips.

 

[Khron]

Maybe i'm the weirdo here, but i've got my irons running at 305C Granted, Ersa and JBC respectively; likely couldn't get away with that with a chinese 936 knockoff...

 

[Tubetec]

I find optimum temp varies a bit depending on the job , how much metal your trying to heat up on the component or board and the size of the tip , 300-320c is usually my starting point , its better to start a little low and adjust upwards if required rather than over doing it and causing damage .

 

[Khron]

Much depends on the thermal capacity & transfer of the tip.

A fat tip at a lower temperature may well do a better job, than a thin but way hotter tip (that cools down as soon as you touch the joint and can't transfer enough heat into the solder).

 

[ccaudle]

Reflow temperatures are typically 260C, so you don't need super high temperatures, you just need enough power capability and thermal transfer efficiency that you can get the joint up above 250C.
That is one of the things I like about the Metcal system, the tips are made from an alloy that varies resistance with temperature, and the power base is a constant current design, so as the tip cools down the power dissipated increases until the tip gets to the correct temperature, at which point the resistance drops and the power dissipated goes back down.

 

[industrialarts]

Which Metcalf models are you guys using? I had never heard of them until mentioned here. I went to look at their site, they seem to be the Cadillac of soldering irons - a little too rich for my blood . But they do seem to be very high quality. How did you come to choose them?

 

[Script]

I'd just clean and wire-jump / bypass the connections. And when confirmed it's working properly, coat it with UV-curing solder mask ink. Could use nail polish instead. -- Adding a subboard sounds way over-the-top. Who cares what it looks like ...

 

[AUDIO FREQ]

I'd just clean and wire-jump / bypass the connections. And when confirmed it's working properly, coat it with UV-curing solder mask ink. Could use nail polish instead. -- Adding a subboard sounds way over-the-top. Who cares what it looks like ...

This is what I am doing at the moment. And it's basically turning it into a point to point....sort of.

 

[ccaudle]

Which Metcalf models are you guys using?

Mine is very old, probably no longer made. SP-PW1-10
I bought it on ebay from a telco design company that was shutting down some labs after the telco contraction in 2001 right after the dot-com bust.

How did you come to choose them?

The techs where I used to work always used Metcal, almost to the point of not willing to use anything else. I figured since they had to repair and rework circuit boards all day long for their job they were probably a trustworthy reference.

 

[kingcredie]

I got this old board I used as a donor/experimentation learning tool. I’d like to now turn it into something.

Any good ways to fill in the pcb? Epoxy? Resin? I’ve always wandered how these things are repaired professionally. But any suggestions would be great!

In consideration of long term usage, I think maybe it is a better choice for you to find PCB factory to remake the board.

 

[Khron]

In consideration of long term usage, I think maybe it is a better choice for you to find PCB factory to remake the board.

... But then one must really wonder whether the time, effort and financial investment is really worth it.

 

[AUDIO FREQ]

Hey guys...this project isn't something terribly important. It's just a spare board that was from a dead unit I had lying around, that I would poach parts off of and learn on, especially how multi-layered pcb's work and how the traces can short out between the layers and how to fix it. So I thought id use some spare parts I have accumulated over there years and create a working unit. All the while trying to optimize performance and make some experimental changes to each section (mic preamp, compressor, eq, master out). So with $0 dollars spent, I managed to trace the short in between the layers, repair all the ripped off pads and traces, make some changes, get it operational, AND learn alot from you guys here on this forum. So thank you everyone!