Topics

Replacing SMD component


R. Tyson
 

Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device. Ten SMD 2N3904 transistors arrived with the mail today. Wow, they are so small. I had previously found the location of Q90 on the board and verified it was no longer functioning and noted it's position, which is not too bad to get at. I am now waiting for a 1mm tip for my soldering iron and more importantly some liquid flux.

Meanwhile I had a look at YouTube and found some ideas for replacing SMD components without special tools. I opted for the following idea, photos below.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR


Bill Bates
 

I think I  would have simply used a junior hacksaw to cut a "fork" in the cut down soldering bit (Maybe have to bend the prongs out?), but it's scarier to contemplate than it is to do, I'm a senior to & I managed to change Q90 ok! God bless,  Bill, G6ATO

On 8 Sep 2020 15:27, "R. Tyson via groups.io" <tysons2@...> wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device. Ten SMD 2N3904 transistors arrived with the mail today. Wow, they are so small. I had previously found the location of Q90 on the board and verified it was no longer functioning and noted it's position, which is not too bad to get at. I am now waiting for a 1mm tip for my soldering iron and more importantly some liquid flux.

Meanwhile I had a look at YouTube and found some ideas for replacing SMD components without special tools. I opted for the following idea, photos below.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR


JE Jesson
 

In a pinch, a toothpick with a bit of clay helps position the surface mounted part into position and soldering one leg to anchor the part.  Solder the other leg and make sure both sides are glossy. 

Joe W2JEJ

On Tue, Sep 8, 2020 at 10:27 AM R. Tyson via groups.io <tysons2=btinternet.com@groups.io> wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device. Ten SMD 2N3904 transistors arrived with the mail today. Wow, they are so small. I had previously found the location of Q90 on the board and verified it was no longer functioning and noted it's position, which is not too bad to get at. I am now waiting for a 1mm tip for my soldering iron and more importantly some liquid flux.

Meanwhile I had a look at YouTube and found some ideas for replacing SMD components without special tools. I opted for the following idea, photos below.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR


Ashhar Farhan
 

Here is what I do. I am quite butterfingers at this, btw.
I use whatever soldering iron I have, and then (hear this, the transistor is dead anyway), i load up liberal bits of solder on all the pads. solder helps in retaining the heat for the next step. next, i start to heat the pads, one by one, waiting until one is melted then move to the other. at the same time use a toothpick to gently keep pushing the transistor away. at some point, all the three will be simulatenously melted enough for the transistor to fly away. Many a times, it comes stuck to the iron itself (i use the iron to push it away - bad boy, i am). 
- f 

On Tue, Sep 8, 2020 at 10:29 PM JE Jesson <jejesson4@...> wrote:
In a pinch, a toothpick with a bit of clay helps position the surface mounted part into position and soldering one leg to anchor the part.  Solder the other leg and make sure both sides are glossy. 

Joe W2JEJ

On Tue, Sep 8, 2020 at 10:27 AM R. Tyson via groups.io <tysons2=btinternet.com@groups.io> wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device. Ten SMD 2N3904 transistors arrived with the mail today. Wow, they are so small. I had previously found the location of Q90 on the board and verified it was no longer functioning and noted it's position, which is not too bad to get at. I am now waiting for a 1mm tip for my soldering iron and more importantly some liquid flux.

Meanwhile I had a look at YouTube and found some ideas for replacing SMD components without special tools. I opted for the following idea, photos below.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR


Dj Merrill
 

A cheap rework station works wonders for removing SMD components.  I picked up this one last year and it does the job adequately:

https://www.amazon.com/gp/product/B07G7BH4HY/

-Dj


Chris Weiss <cweiss@...>
 

+1 on the rework station - otherwise, look into solder braid. It's highly-conductive copper weave (about shoelace size). You put it against the component and your iron against it and it wicks up the solder - I've found it _very_ effective for removing both SMD and through-hole components. It's also cheap and lasts forever. 

Be really careful when pulling on things, it's possible to pull the solder pad up off the board which can be a pain to work around.





On Tue, Sep 8, 2020 at 10:56 AM Dj Merrill via groups.io <groupsio=deej.net@groups.io> wrote:
A cheap rework station works wonders for removing SMD components.  I
picked up this one last year and it does the job adequately:

https://www.amazon.com/gp/product/B07G7BH4HY/

-Dj







--
-Chris


R. Tyson
 

Hi Bill,
Thanks for the comment. I had seen a video where the tip is sliced with a hacksaw blade and then the ends bent to suit. However, I was feeling lazy and decided to just go with wrapping the wire and forming the two prongs from that.

I think I also had at the back of my mind that I could remove the wire and replace it with another winding with longer prongs if I needed to try and get an I.C. off at some time on a future project.

I have steered clear of working with SMD devices until now (fear) but realise that as they are now in common use I am going to have to try working with them. It looks as if they could actually be easier to work with given some time and experience and maybe a hot air system. From videos I have watched it seems that plenty of flux is a requirement for success.

Reg           G4NFR


R. Tyson
 

Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm.

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.

Reg                     G4NFR


pat griffin
 

I'm on the late bus-I just saw this email.
I was in the same boat as you a couple of years ago.  I found that a small-tipped solder station (the $20-$30 kind.  I'm not at home and don't remember the one I bought)  works well.  Put a dab of solder on the pads, rest you hand against something to steady it, lock the part down with a clip, tape, a fishing weight, etc and quickly solder it.  You'll get the hang of it.  As far as paste goes, a cheap toaster oven works well.  I built a temperature gauge but it is really not necessary.  Put the board in the oven, turn on the heat and watch until the paste gets silver and turn off the oven.  Let it cool and you are done. I've only done this with new boards.  It may not work very well for replacement of parts.
73,
Pat AA4PG


http://www.cahabatechnology.com


From: BITX20@groups.io <BITX20@groups.io> on behalf of R. Tyson via groups.io <tysons2@...>
Sent: Tuesday, September 8, 2020 12:48 PM
To: BITX20@groups.io <BITX20@groups.io>
Subject: Re: [BITX20] Replacing SMD component
 
Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm.

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.

Reg                     G4NFR


Black Wolfe
 


On 9/8/20 10:27 AM, R. Tyson via groups.io wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR
_._,_._,_

If it works it is good enough.  I invested in a hot air soldering gun last year to move the memory chip from a failed hard drive to a new logic board.  (The chip contains the sector error table and must go with the platters it is written for)

Surprisingly the job was not all that difficult.  Unfortunately it was not quite enough fix to access my files.  I'm still working on that.

Bruce W.      ~KV4OE~


Owen Vinall
 

This info is just in time for my own attempts at working on Smd's. Some great tips thanks for all of them. I am thinking of making some Smd bits for my rather old Weller iron using some modified copper pipe pieces. Re Bad Tracks on Hard drives. I used to rebuild (not real rebuilding) Mainfram disc packs. You had to run a program to detect bad tracks then add them to the bad tracks directory then copy all the data back. Crude version of Defrag I guess. I wondered how consumer grade discs handled that issue.
Re Smd's I am making a simple Web cam Microscope so I can see what I am doing. So far I disassembled a spare web cam that is no longer supported by current W. Plugged it into a spare Raspberry Pi usb port running Raspbian (Debian). Fired up Vlc and it recognised the web cam. With the web cam lens removed and a spare Slr lens reverse mounted against it I can see fairly clearly the many 3 coloured dots on my monitor. They are quite large. I have 3d printed a number of holders to hold the reversed lens and the modified web cam so It's now a matter of tidying it up. Just use Dr Google. You will need plenty of light but that's easy.

Sorry if this is rather long.

73 Owen

On Wed, 9 Sep 2020, 6:22 am Black Wolfe, <blackwolfe@...> wrote:


On 9/8/20 10:27 AM, R. Tyson via groups.io wrote:
Hi,

Due to a senior moment ( I am old enough to be entitled to have them) I need to replace Q90 which is a dreaded SMD device.

I cut down an old, knackered soldering bit and cleaned it up as shown in the photo. I then applied some heat conducting paste (probably not essential but I already had some). I then wound 1mm copper wire onto the remains of the soldering iron tip. The two prongs that are formed should enable me to heat all 3 connections on the transistor at the same time and it (should) come off the board easily. Well.... it looks easy when the guys do it on YouTube !

Reg                   G4NFR


Clark Martin
 

For SMD I’ve found the following helpful.
Headset magnifier
fine tweezers
practice
Both with a conventional soldering iron and my hot air rework station, I practiced on desoldering components till I got a feel for it.  I also soldered a few recently removed parts back on to the board for practice at installing parts.

Clark Martin
KK6ISP

On Sep 8, 2020, at 11:48 AM, R. Tyson via groups.io <tysons2@...> wrote:

Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm. 

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.


Shirley Dulcey KE1L
 

Replacing SMD components is easy -- I find it much easier to do than replacing through-hole parts. I've had a V3 on the shelf for a while that I'm now trying to put into use and I'm stuck on replacing the relays -- I can't get the existing ones off the board :(


On Tue, Sep 8, 2020 at 7:26 PM Clark Martin <kk6isp@...> wrote:
For SMD I’ve found the following helpful.
Headset magnifier
fine tweezers
practice
Both with a conventional soldering iron and my hot air rework station, I practiced on desoldering components till I got a feel for it.  I also soldered a few recently removed parts back on to the board for practice at installing parts.

Clark Martin
KK6ISP

On Sep 8, 2020, at 11:48 AM, R. Tyson via groups.io <tysons2@...> wrote:

Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm. 

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.


Gordon Gibby
 

Cut them apart and remove them one pin at a time


On Sep 8, 2020, at 19:41, Shirley Dulcey KE1L <mark@...> wrote:


Replacing SMD components is easy -- I find it much easier to do than replacing through-hole parts. I've had a V3 on the shelf for a while that I'm now trying to put into use and I'm stuck on replacing the relays -- I can't get the existing ones off the board :(


On Tue, Sep 8, 2020 at 7:26 PM Clark Martin <kk6isp@...> wrote:
For SMD I’ve found the following helpful.
Headset magnifier
fine tweezers
practice
Both with a conventional soldering iron and my hot air rework station, I practiced on desoldering components till I got a feel for it.  I also soldered a few recently removed parts back on to the board for practice at installing parts.

Clark Martin
KK6ISP

On Sep 8, 2020, at 11:48 AM, R. Tyson via groups.io <tysons2@...> wrote:

Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm. 

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.


Ashhar Farhan
 

I dremel out the bad relays. I work at slicing out the plastic cover then take out each exposed pin. 


On Wed 9 Sep, 2020, 5:23 AM Gordon Gibby, <docvacuumtubes@...> wrote:
Cut them apart and remove them one pin at a time


On Sep 8, 2020, at 19:41, Shirley Dulcey KE1L <mark@...> wrote:


Replacing SMD components is easy -- I find it much easier to do than replacing through-hole parts. I've had a V3 on the shelf for a while that I'm now trying to put into use and I'm stuck on replacing the relays -- I can't get the existing ones off the board :(


On Tue, Sep 8, 2020 at 7:26 PM Clark Martin <kk6isp@...> wrote:
For SMD I’ve found the following helpful.
Headset magnifier
fine tweezers
practice
Both with a conventional soldering iron and my hot air rework station, I practiced on desoldering components till I got a feel for it.  I also soldered a few recently removed parts back on to the board for practice at installing parts.

Clark Martin
KK6ISP

On Sep 8, 2020, at 11:48 AM, R. Tyson via groups.io <tysons2@...> wrote:

Thanks for all the comments and useful tips guys. All noted. If I get the idea of playing around with SMD parts I will look at getting a hot air system. Playing around with SMD parts may well be forced on me as they become increasingly the norm. 

I should have everything I need delivered in the next couple of days. I then need a nice sunny day for plenty of bright, natural light. After sacrificing several small fluffy toys to appease the gods I will then give it my best shot.


 

Farhan,

Never had a problem, desoldered the relay pins with a weller and the relays fell out. No damage to any
of your boards and all relays intact. On one board I tried many brands of relsy during the hunt for the
deverishes.

Raj


At 09/09/2020, you wrote:
I dremel out the bad relays. I work at slicing out the plastic cover then take out each exposed pin.Â

On Wed 9 Sep, 2020, 5:23 AM Gordon Gibby, <docvacuumtubes@... > wrote:
Cut them apart and remove them one pin at a time


On Sep 8, 2020, at 19:41, Shirley Dulcey KE1L <mark@...> wrote:


Replacing SMD components is easy -- I find it much easier to do than replacing through-hole parts. I've had a V3 on the shelf for a while that I'm now trying to put into use and I'm stuck on replacing the relays -- I can't get the existing ones off the board :(


Ralph Mowery
 

The hot air rework station is the way to go.  You can get them for under $70 in many cases.  Then some fine solder.  Get some Kapton heat resistant tape and put over the device to be removed if near other components and cut a hole in it over what you want to remove.  Some solder around .015 of the old tin/lead is best to use if you can get in your country.  Look on youtube on how to use the equipment.  I was over 60 when I started on the SMD.  Get an old computer board with some SMD on them and practice .  I did buy an Amscope SE-400z microscope for around $ 200.  I find that I am using that a lot now at my age and eyesight.  Usually use the 10x lenses with it.  That scope has plenty of work space under it.

I find the SMD very easy to work with in many cases with the small tools.  Look for a young man named Rossman on you tube and someof his older shows on the smd and tools.

Ralph ku4pt


Dallas
 

At 65 years old I concur everyone should have a macro scope.  I also like an adjustable zoom and a long arm mounting stand. I started using one 40 years ago at work.  I had excellent vision back then but got addicted to the extended vision the scope gave me. After leaving that job I bought myself one for personal use.  I bought another better one on eBay 10-15 years ago when the imported stuff started showing up at low prices. I also recommend the LED ring light attachment that fits around the lens.  One other thing to watch for is an auxiliary screw-on lens that will move the focal plane 8-10 inches further away from the objective lens, this gives your hands room to work on what you are looking at.  You will use it for much more than SMD’s.

Dallas
N5fee


R. Tyson
 

Update,

The tiny toasting fork I made to remove SMD components didn't work. I had used enamel coated wire and it just wasn't transferring heat that well. A quick think... the solder on the tip of the iron transfers heat to the joint... O.K let's try again.
I made a new, tiny toasting fork out of bare copper wire and tinned the prongs. Bingo.. it was now like shelling peas. I had an old computer board to try it out on and it was removing components without any pushing, pulling, twisting or anything. Just hold it in place, the solder melts and the component comes off attached to one of the prongs - a quick flick and that's it the prongs are ready for the next component removal. The MAGIC ingredient is flux. I am using liquid flux but gel would do.

I can quickly clean the pads with solder wick braid and that again works much better when used with plenty of flux. I should have time tomorrow to have a go at replacing Q90.

I feel as though I am moving towards the dark side... never thought I would be playing with SMD devices. Aged 76 I had better crack on as time gets more pressing !

Reg               G4NFR


R. Tyson
 

Oh well !  I was going to wait until tomorrow but impatience (and curiosity) got the better of me.

I have some LED lights above the workbench (Wow ! That's a fancy name for it) so I decided to have a go at removing Q90.

Plenty of flux and the tiny toasting fork did its job and the speck of dust that is Q90 was safely off the board. More flux on the pads and de-soldering braid and a hot iron cleaned up the pads. So far so good.

Tomorrow I will try and install the new speck of dust... er, I mean Q90 transistor. I have 10 of them so I can afford to sneeze 9 times.....  photo of what awaits Q90 below not very good but it was LED lighting.