# Messed Up PCB Pads? New PCB?



## joelorigo (Jul 19, 2020)

I got to the last component on the Duocast PCB when I noticed I installed the 8 pin IC socket in upside down. Trying to get it out I think I messed up a couple of the pads. What would be the options here? Finish it and see if it works? Buy a replacement PBC and take all the parts out of the old board and install on the new board?
I can't believe I did this


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## Nostradoomus (Jul 19, 2020)

Just the socket? That doesn’t matter, put the IC in the right way and it’ll be fine.


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## twebb6778 (Jul 19, 2020)

Just like Nostradoomus said, the orientation of the socket is irrelevant. As long as the IC itself is the correct orientation it'll work.

Personally, I think this circuit is a lot more interesting at 9v anyway. I just left the charge pump out of my simulcast.


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## joelorigo (Jul 19, 2020)

A


Nostradoomus said:


> Just the socket? That doesn’t matter, put the IC in the right way and it’ll be fine.


Ahh, I wish I posted here BEFORE I tried to remove it. It’s all messed up now


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## joelorigo (Jul 19, 2020)

twebb6778 said:


> Just like Nostradoomus said, the orientation of the socket is irrelevant. As long as the IC itself is the correct orientation it'll work.
> 
> Personally, I think this circuit is a lot more interesting at 9v anyway. I just left the charge pump out of my simulcast.



At this point it seems the smartest thing for me to do is just finish it and not worry about the charge pump ic.

So I assume then there’s no need to add the external voltage switch? The one that switches from 9v to 27v? Since sending the signal through the ic is how it becomes 27v, right?

And it will still work with this cracked in half socket and a couple of messed up pads?


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## twebb6778 (Jul 19, 2020)

Correct. If you follow the schematic you can see where the IC is that increases the voltage. You can just follow the highlighted path, ignore everything below it, and you should be sweet! It looks like the LT1054 also integrates the switchable gain option, so unfortunately you'll also lose this too.


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## joelorigo (Jul 19, 2020)

twebb6778 said:


> Correct. If you follow the schematic you can see where the IC is that increases the voltage. You can just follow the highlighted path, ignore everything below it, and you should be sweet! It looks like the LT1054 also integrates the switchable gain option, so unfortunately you'll also lose this too.
> 
> View attachment 5524


Oh no, you mean the foot switch that switches to the higher gain mode? So it wouldn’t be able to do the high gain mode?


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## twebb6778 (Jul 19, 2020)

Actually I think you should be ok. Looking at the schematic again I think the gain and bypass footswitches should work normally.

I am a little confused by SW3 in the schematic (highlighted). The two 3PDT's and SPDT for voltage are all accounted for in the build docs, but not SW3.





If you're leaving out the IC and want to hard wire it for 9v, you'll also need to short these two pads (in red):


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## joelorigo (Jul 19, 2020)

twebb6778 said:


> Actually I think you should be ok. Looking at the schematic again I think the gain and bypass footswitches should work normally.
> 
> I am a little confused by SW3 in the schematic (highlighted). The two 3PDT's and SPDT for voltage are all accounted for in the build docs, but not SW3.



Ok, that's good news. I purposefully waited for this dual foot switch version.

Also, for anyone else reading this, any confirmation on what SW3 is?


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## joelorigo (Jul 19, 2020)

twebb6778 said:


> If you're leaving out the IC and want to hard wire it for 9v, you'll also need to short these two pads (in red):
> 
> View attachment 5526



Will do, thanks! 

Although, if I don't do this jumper, would you be able to use a higher voltage power adaptor, or a voltage doubler to run at 18v?


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## twebb6778 (Jul 19, 2020)

You'll still need to use a jumper there in place of the switch, because there's nothing for the switch to switch to, if that makes sense. Without something bridging those two pads, either a jumper or a switch, your board won't get power.

As long as your components are rated for at least 25v, I think you'll be able to use an 18v power supply with this if you decide you want to try it.


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## joelorigo (Jul 20, 2020)

twebb6778 said:


> You'll still need to use a jumper there in place of the switch, because there's nothing for the switch to switch to, if that makes sense. Without something bridging those two pads, either a jumper or a switch, your board won't get power.
> 
> As long as your components are rated for at least 25v, I think you'll be able to use an 18v power supply with this if you decide you want to try it.



Oh right, I'll have to double check the voltage one all the components. 

And yes that does make sense about the switch/jumper/power issue

Thanks


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## Robert (Jul 20, 2020)

joelorigo said:


> Also, for anyone else reading this, any confirmation on what SW3 is?



SW3 is the solder jumper pads on the bottom of the board (under the charge pump IC)...   these are for using a 7660 or 1044 type charge pump instead of LT1054.


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## twebb6778 (Jul 20, 2020)

SW3 is really obvious now that you mention it, thanks!

@music6000 those jumpers look correct to me.


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## joelorigo (Jul 20, 2020)

twebb6778 said:


> SW3 is really obvious now that you mention it, thanks!
> 
> @music6000 those jumpers look correct to me.



Oh where did that post go from @music6000 ? I'm not sure what that was implying


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## music6000 (Jul 20, 2020)

This should help if you want to try jumpers to the Op Amp Socket.
Pins 3 & 5 go to Ground.
Pins 1, 4, 6 & 7 are not used with LT1054, Somebody jump in if this is not Correct! :


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## joelorigo (Jul 20, 2020)

music6000 said:


> This should help if you want to try jumpers to the Op Amp Socket
> Pins 1, 4, 6 & 7are not used with LT1054, Somebody jump in if this is not Correct! :


Assuming this is correct, are you saying I would have to do more than jumper those first 2 SPDT pads that was previously mentioned?


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## music6000 (Jul 20, 2020)

joelorigo said:


> Assuming this is correct, are you saying I would have to do more than jumper those first 2 SPDT pads that was previously mentioned?


This is for correcting any damage if you use an Op Amp socket & LT1054 to be able to switch from 9v to 27v again.


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## joelorigo (Jul 20, 2020)

music6000 said:


> This is for correcting any damage if you use an Op Amp socket & LT1054 to be able to switch from 9v to 27v again.



Ah! I think I see. If I take the socket out, I can insert the LT1054, use the SPDT switch, and in case any pads are damaged, doing the jumpers you highlighted - it will work as originally intended?


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## music6000 (Jul 20, 2020)

joelorigo said:


> Ah! I think I see. If I take the socket out, I can insert the LT1054, use the SPDT switch, and in case any pads are damaged, doing the jumpers you highlighted - it will work as originally intended?


I would still use a Socket again, Heat is your worst enemy with Op Amps!
I would use 24 gauge hook up wire & twist the tinned wires.
Wrap around a safety pin twice then cut of excess and slide over Op Amp Pin & solder:


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## joelorigo (Jul 20, 2020)

music6000 said:


> I would still use a Socket again, Heat is your worst enemy with Op Amps!
> I would use 24 gauge hook up wire & twist the tinned wires.
> Wrap around a safety pin twice then cut of excess and slide over Op Amp Pin & solder:
> 
> View attachment 5533


OK sounds good. 
Regarding your diagram above, just to be clear since I am new at this, I would jump from the "8" you highlighted on the SPDT pin, to "8" on the D5 diode to "8" on the D100 diode to the "8" on the IC to "8" on the D1 diode? And a separate jump that goes from "2" on the IC to "2" on C12 and to "2" on  C14? And "G" to "G" on the IC pins? Like this?


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## music6000 (Jul 20, 2020)

You would just need this.
It would all be done on the reverse side so you don't see it :


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## joelorigo (Jul 20, 2020)

music6000 said:


> You would just need this.
> It would all be done on the reverse side so you don't see it :
> View attachment 5538


Got it. Thank you. 

I currently only have 22 gage solid wire. Would that work?


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## joelorigo (Jul 20, 2020)

So, if I understand everything correctly, I can:

1. Remove and replace the socket, and even if a couple of the pads are bad, it will work as normal if I do the jumpers above.
2. Hard wire it for 9v by doing not using the IC or the SDPT switch and jumping then 2 switch pads (what is suggested in reply 8 of this thread).


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## music6000 (Jul 20, 2020)

Yes, 1, 4, 6 & 7 dont need to be connected, you can put some solder on them to give the socket some more strength onto the PCB.
22 gauge should be fine.


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## joelorigo (Jul 23, 2020)

I received a new socket today and I though of another question.

When I was saying I might of "messed" a pad it was only a couple on the bottom. How does one tell if a pad is "messed" up on the PCB? Could I try without doing any jumpers and see if it works?


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## twebb6778 (Jul 23, 2020)

You can use your DMM to test for continuity between points that are supposed to be connected. 

Use the colours in the pictures above. You should get continuity between any red pad to another red pad. Then check yellow, then blue.


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## joelorigo (Jul 23, 2020)

twebb6778 said:


> You can use your DMM to test for continuity between points that are supposed to be connected.
> 
> Use the colours in the pictures above. You should get continuity between any red pad to another red pad. Then check yellow, then blue.


Thanks, I'll try it


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## joelorigo (Jul 23, 2020)

Only the yellow ones got continuity. And the IC blue pad looks fine. Then, I noticed I had the D5 diode in backward. Got it out but having trouble getting it back in the right way. Ughh, this project is cursed


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## twebb6778 (Jul 24, 2020)

You'll need to add jumpers wherever you don't have continuity.

If you've got a solder sucker or solder wick that can help you remove excess solder before trying to reinstall a component. If you're having trouble getting it back in the right way, just go one leg at a time. Get it most of the way through with one leg, then work on the other leg. Let the pads cool down for 20 seconds before each attempt so they're not being heated for too long.


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## joelorigo (Jul 24, 2020)

OK, that makes sense, I will try one leg at a time. I might have damages these pads as well however.


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## twebb6778 (Jul 24, 2020)

Take your time 

Once it's in post some photos and do some more continuity tests. If you're not getting continuity you can always add some jumpers.


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## joelorigo (Jul 24, 2020)

twebb6778 said:


> Take your time
> 
> Once it's in post some photos and do some more continuity tests. If you're not getting continuity you can always add some jumpers.


Yes, I will be more patient and always try to double check in the future.

Anyway I got the diode in the correct way. Still the same continuity result - just the yellow from the above diagram. However, I do not yet have the new socket soldered in yet. Should I do that and check again?

EDIT: I placed it in without soldering and now I have continuity with the blue and yellow


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## music6000 (Jul 24, 2020)

Yes , make sure the Socket is facing the right way & all the way in.
Test for Continuity again after Soldering on the 3 Colours on all the pads marked.


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## joelorigo (Jul 24, 2020)

Ok, soldered the socket and now it is back to just the yellow showing continuity. Also, I was having a hard time getting the solder to drop around the socket's pins, it kept collecting on the iron. Could that be because the metal on the PCB pads are damaged? And looks like I need to jumper the red and the blue paths


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## zgrav (Jul 24, 2020)

hard to solder a pin in place if the pad is gone that it would have been soldered to.  but solder in all the pins you can, and then use jumpers on the pins where you do not have the indicated connectivity.


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## joelorigo (Jul 24, 2020)

zgrav said:


> hard to solder a pin in place if the pad is gone that it would have been soldered to.  but solder in all the pins you can, and then use jumpers on the pins where you do not have the indicated connectivity.


Ok got it. Based on how this project is going, this should be I interesting ?


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## joelorigo (Jul 25, 2020)

I added the blue and red jumpers as directed above. Now shows continuity on the blue, red and yellow points. Yay!

In regard to the D5 diode I had to extract and replace correctly, how do I know if I damaged either of those pads?

And, can I proceed to add the IC in the socket and finish the build?


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## music6000 (Jul 25, 2020)

D5 Continuity Check - Left side to GROUND (Yellow Trace)
                                    Right side to Right side D100 & Op Amp Pin 8 (Red Trace)


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## joelorigo (Jul 26, 2020)

music6000 said:


> D5 Continuity Check - Left side to GROUND (Yellow Trace)
> Right side to Right side D100 & Op Amp Pin 8 (Red Trace)
> 
> View attachment 5618



Left side (yellow) - Yes
Right side - No

So jump the right side of D5 to Right side D100?


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## music6000 (Jul 26, 2020)

joelorigo said:


> Left side (yellow) - Yes
> Right side - No
> 
> So jump the right side of D5 to Right side D100?


Yes!, & there should be continuity to Op Amp Pin 8 & left side of D1 (RED).


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## joelorigo (Jul 26, 2020)

music6000 said:


> Yes!, & there should be continuity to Op Amp Pin 8 & left side of D1 (RED).


Done and there is continuity to Op Amp Pin 8 & left side of D1.
Here is a photo of my jumping. Is it ok to continue with the build now?


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## music6000 (Jul 26, 2020)

Yes, Put the Op Amp in & Test all the matching pads below:


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## joelorigo (Jul 27, 2020)

Test was good! It's all done and sounds great!

I learned a lot on this one. Thank you all for taking the time to help a noob and  getting me through this.


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