Si5351A blown (IC1) QCX transceiver.


William Jenrick
 

Has anyone been able to replace IC!, surface mounted, successfully?
If so, please give me your secrets. I have a Hubal magnifying lighted desk lamp and needle soldering iron by the way. An and also a NASA certified soldering certificate/ circa 1966!!!!!


geoff M0ORE
 

Use a soldering iron with a larger bit then use a solder wick to remove excess. A needle point tip does not hold enough heat and will do more damage. Don't try to save the old chip. Cut the legs and remove one at a time.

On 24/02/2021 23:53, William Jenrick wrote:
Has anyone been able to replace IC!, surface mounted, successfully?
If so, please give me your secrets. I have a Hubal magnifying lighted desk lamp and needle soldering iron by the way. An and also a NASA certified soldering certificate/ circa 1966!!!!!


Steve Z
 

One word: ChipQuik. Reduce the iron temp to 450C, and coat those pins with tons of ChipQuik, keep both sides heated and the chip will slide right off.

Steve N9SZ


Steve Z
 

Oops, I mean 450F.


mike.carden
 



On Thu, Feb 25, 2021 at 12:19 PM Steve Z <zabarnick@...> wrote:
Oops, I mean 450F.

Whew. I usually solder at 370C so I really was wondering what your PCBs look like. :)

--
MC
VK1MC

 


Mont Pierce KM6WT
 

Personally, I would not "cut the legs"... I'm too afraid of damaging those tiny pads.  But, that's just me.

After using solder wick to remove as much solder as possible, you can heat the pins on one side and lift them slightly with an exacto knife.
Once the pins are lifted on one side, the part should slide right off when the pins on the other side are heated.

I second Steve's comment on ChipQuik.  It's pretty cool.  I've never used it.  But seen several YouTube vids (click here) removing square chips with pins on all four sides.  Just be sure to wick the pads clean to remove all the ChipQuick before soldering in new chip.

Search YouTube for "how to remove smd ic with soldering iron" (click here)
after watching a few of these, you will feel more comfortable about doing it, and you may find some other ideas you like.


I second Geoff's comment on using a broad tip.  It'll help when removing the chip, as you can heat all the pins at once.
Also, there's no need to try to solder each pin individually.

I used to try to solder each pin very carefully to avoid solder bridges, until I learned how easy it is just to remove the bridge later...

Once all the pins are soldered, here's two easy ways to remove solder bridges:
1) use solder wick to wick away the excess solder.
2) I like to hold the board up-side-down while heating the pins with the soldering iron.  Gravity will pull the excess solder onto the iron.


Practice First: If you have any old boards available that you don't care about, practice on them until you feel comfortable with the process.



73
km6wt


William Jenrick
 

Tnx.....I cut the chip in 1/2 and gilded an iron over each side which worked well. I didn't cut any of the legs, just the chip....Now, soldering a new chip in place is going to be a challenge!!!!!

On Wed, Feb 24, 2021 at 6:04 PM Mont Pierce KM6WT <de.km6wt@...> wrote:
Personally, I would not "cut the legs"... I'm too afraid of damaging those tiny pads.  But, that's just me.

After using solder wick to remove as much solder as possible, you can heat the pins on one side and lift them slightly with an exacto knife.
Once the pins are lifted on one side, the part should slide right off when the pins on the other side are heated.

I second Steve's comment on ChipQuik.  It's pretty cool.  I've never used it.  But seen several YouTube vids (click here) removing square chips with pins on all four sides.  Just be sure to wick the pads clean to remove all the ChipQuick before soldering in new chip.

Search YouTube for "how to remove smd ic with soldering iron" (click here)
after watching a few of these, you will feel more comfortable about doing it, and you may find some other ideas you like.


I second Geoff's comment on using a broad tip.  It'll help when removing the chip, as you can heat all the pins at once.
Also, there's no need to try to solder each pin individually.

I used to try to solder each pin very carefully to avoid solder bridges, until I learned how easy it is just to remove the bridge later...

Once all the pins are soldered, here's two easy ways to remove solder bridges:
1) use solder wick to wick away the excess solder.
2) I like to hold the board up-side-down while heating the pins with the soldering iron.  Gravity will pull the excess solder onto the iron.


Practice First: If you have any old boards available that you don't care about, practice on them until you feel comfortable with the process.



73
km6wt



--
William Jenrick 


William Jenrick
 

Looks like a dream and worked well from the start only having to take 5 turns off the 'toroid from hell' to tune it up. Then after a week, IC1 took a dump. I have a variable heat range soldering iron by the way and am certified by NASA for soldering.


On Wed, Feb 24, 2021 at 5:36 PM mike.carden <mike.carden@...> wrote:


On Thu, Feb 25, 2021 at 12:19 PM Steve Z <zabarnick@...> wrote:
Oops, I mean 450F.

Whew. I usually solder at 370C so I really was wondering what your PCBs look like. :)

--
MC
VK1MC

 



--
William Jenrick 


William Jenrick
 

Getting the bad chip off was not the problem. I first cut the chip in 1/2 with flush cutter dikes and heated both sides and it fell off nicely. My question is how do you solder the new chip in place. I have 5 of them coming in sourced locally ($.89/each).....I guess I could glue the chip to the pcb first and then solder it(????)
Tnx for the tip about chip quik. I just ordered some from Amazon...

On Wed, Feb 24, 2021 at 4:26 PM Steve Z <zabarnick@...> wrote:
One word: ChipQuik. Reduce the iron temp to 450C, and coat those pins with tons of ChipQuik, keep both sides heated and the chip will slide right off.

Steve N9SZ



--
William Jenrick 


mike.carden
 



On Thu, Feb 25, 2021 at 1:26 PM William Jenrick <wjenrick1@...> wrote:
Getting the bad chip off was not the problem. I first cut the chip in 1/2 with flush cutter dikes and heated both sides and it fell off nicely. My question is how do you solder the new chip in place. 

Gently clean the pads with solder wick. Apply liquid flux from a flux pen or gel flux from a syringe. Tin one corner pad with a small amount of solder. Place the chip on the PCB, triple checking that it's the right way around. Hold it there with tweezers, a toothpick - whatever you have that you can hold it down with. Apply the soldering iron to the pin that's on the corner you applied solder to. Check that the chip still has its pins aligned with all the pads. If not, reheat and nudge until it's right. Then apply solder and the iron to the pins on the OTHER SIDE of the chip from where you started. Don't worry about bridges, just get the solder on there. Then back to the side you started and do the same. To finish off, apply some more flux and the solder wick to clear out the bridges. Then use either isopropyl alcohol or spray PCB cleaner with a brush to tidy up, and finally, inspect your beautiful work with a jeweller's loupe.

--
MC
VK1MC

 


Mike Easterbrook
 

I've successfully used ChipQuick several(!) times to remove Si5351 from QCX original & Mini boards. Clean-up of pads easy with fluxed cotton bud. What continues to frustrate is eliminating bridges between pins on the replacement chip. Fluxed bud and solder wick ineffective (thus the several removals).  Any tips? - my stock of  5351s is rapidly diminishing!
Thanks Mike 9M2LXM

On Thu, 25 Feb 2021, 10:04 Mont Pierce KM6WT, <de.km6wt@...> wrote:
Personally, I would not "cut the legs"... I'm too afraid of damaging those tiny pads.  But, that's just me.

After using solder wick to remove as much solder as possible, you can heat the pins on one side and lift them slightly with an exacto knife.
Once the pins are lifted on one side, the part should slide right off when the pins on the other side are heated.

I second Steve's comment on ChipQuik.  It's pretty cool.  I've never used it.  But seen several YouTube vids (click here) removing square chips with pins on all four sides.  Just be sure to wick the pads clean to remove all the ChipQuick before soldering in new chip.

Search YouTube for "how to remove smd ic with soldering iron" (click here)
after watching a few of these, you will feel more comfortable about doing it, and you may find some other ideas you like.


I second Geoff's comment on using a broad tip.  It'll help when removing the chip, as you can heat all the pins at once.
Also, there's no need to try to solder each pin individually.

I used to try to solder each pin very carefully to avoid solder bridges, until I learned how easy it is just to remove the bridge later...

Once all the pins are soldered, here's two easy ways to remove solder bridges:
1) use solder wick to wick away the excess solder.
2) I like to hold the board up-side-down while heating the pins with the soldering iron.  Gravity will pull the excess solder onto the iron.


Practice First: If you have any old boards available that you don't care about, practice on them until you feel comfortable with the process.



73
km6wt


William Jenrick
 

Your the man!!!! Tnx


On Wed, Feb 24, 2021, 6:37 PM mike.carden <mike.carden@...> wrote:


On Thu, Feb 25, 2021 at 1:26 PM William Jenrick <wjenrick1@...> wrote:
Getting the bad chip off was not the problem. I first cut the chip in 1/2 with flush cutter dikes and heated both sides and it fell off nicely. My question is how do you solder the new chip in place. 

Gently clean the pads with solder wick. Apply liquid flux from a flux pen or gel flux from a syringe. Tin one corner pad with a small amount of solder. Place the chip on the PCB, triple checking that it's the right way around. Hold it there with tweezers, a toothpick - whatever you have that you can hold it down with. Apply the soldering iron to the pin that's on the corner you applied solder to. Check that the chip still has its pins aligned with all the pads. If not, reheat and nudge until it's right. Then apply solder and the iron to the pins on the OTHER SIDE of the chip from where you started. Don't worry about bridges, just get the solder on there. Then back to the side you started and do the same. To finish off, apply some more flux and the solder wick to clear out the bridges. Then use either isopropyl alcohol or spray PCB cleaner with a brush to tidy up, and finally, inspect your beautiful work with a jeweller's loupe.

--
MC
VK1MC

 


Ham Radio
 

I have used ChipQuick and it works well.

That stuff does gum up your soldering iron  tip so make sure your iron tip is super clean after using ChipQuick.

Use *lots* of flux when soldering SMT.  As the many videos show, tack down diagonal corners of the chip and then use a small flat tip on your soldering iron and drag the iron tip across the SMT pins.   Magic !   Inspect for bridges with a magnifying lens or eye loop and remove any bridges with solder wick.


73, Bernie, VE3FWF
(most typos in this message have been generated by highly sophisticated auto-correction software)


Matt Burge <matt24512@...>
 

Hi William, i am about to... i have a new chip and i intend to use solder paste & a heat gun... i have purchased an SMD practice board.. i was going to just use the soldering iron method 
but that chip is sooooo dam tiny... its costing a little more to get the equipment together but i am enjoying the challenge.. lol I overheated my chip while searching for another fault to do with the controls board.. good luck 👍


Hans Summers
 

Hi all

Another reminder, just in case it helps anyone: when replacing an Si5351A chip please be sure to purchase Si5351A-B-GT or Si5351A-B-GTR (Matt's appears to be correct). Do not be tempted to buy a part number such as Si5351A-Bxxxxx-GT [R] because the xxxxx indicates it is a customized chip for a particular customer's requirements; these typically operate on I2C bus addresses other than 0x60. These non-standard chips will NOT work in QRP Labs kits. 

73 Hans G0UPL
http://qrp-labs.com

On Thu, Feb 25, 2021 at 8:03 AM Matt Burge via groups.io <matt24512=yahoo.com@groups.io> wrote:
Hi William, i am about to... i have a new chip and i intend to use solder paste & a heat gun... i have purchased an SMD practice board.. i was going to just use the soldering iron method 
but that chip is sooooo dam tiny... its costing a little more to get the equipment together but i am enjoying the challenge.. lol I overheated my chip while searching for another fault to do with the controls board.. good luck 👍


Gwen Patton
 

I splurged and got myself a hot air station. They aren't tremendously expensive. I think I paid about $65 for mine.

When doing SMT work, I have either an iExtruder solder paste dispenser or a tiny manual dispenser I got from Tindie. Then I use syringe-able solder paste and apply to the pads, carefully put the chip onto the pads with a pair of tweezers (I use a lighted magnifier or a LCD microscope), and heat it with the hot air station. When the solder melts, surface tension will practically SUCK the chip into alignment. Let cool, then clean off the flux that was in the solder paste with isopropyl and a swab. I use disposable foam swabs for electronics work, as they don't leave little wisps of cotton fiber everywhere. They get torn up on the board, but don't leave bits for the most part.

If you get a hot air station, removing a chip is easy. Apply some flux (I use Amtech NC-559-V2-TF Tacky Flux in a syringe), then heat the part while holding it with tweezers. When the solder melts, lift the chip off. Then clean up the pads with solder wick and your iron, and clean the board. Then you can apply fresh solder paste to the pads, and hot air solder the new chip in place.

I get the tacky flux from Rossmann Group in New York, a certified Amtech dealer. It's really good flux. I mostly use that for soldering iron work. https://store.rossmanngroup.com/amtech-nc-559-v2-30-cc-16160.html
I get either MG Chemicals T3 solder paste for larger pads, or Chip Quik T5 solder paste for really tiny pads. The really small syringe applicator I have is for the T5. When working with paste, that number matters. The smaller the number, the larger a syringe needle you need for it to flow properly.

https://www.i-extruder.com/en/
https://www.tindie.com/products/avandalen/disper-micro-dot-solder-paste-syringe-dispenser/
Chip Quik T5: https://www.amazon.com/gp/product/B00D2I88PG/
MG T3: https://www.amazon.com/gp/product/B00M1RC0YY

I have 3 soldering irons. A TS-100 with an ILS tip  for fine work, a cheap but temp controlled mains iron from Banggood for connectors, PCB enclosures, and large heat sinks, and a Dremel Versa-Tip butane iron for outdoor work.

TS100: https://www.amazon.com/gp/product/B06XBFTKMY
ILS Tip: https://www.amazon.com/gp/product/B072J75BRT/
https://www.banggood.com/MUSTOOL-MT883-80W-Electric-Solder-Iron-Station-Adjustable-Temperature-180-480-or-392-896-Auto-Sleeping-110V-or-220V-EU-or-US-or-UK-Plug-Option-p-1553736.html
WEP/Kohree Hot Air Station: https://www.amazon.com/Kohree-Rework-Station-Solder-Digital/dp/B00JVM3WBC  (There's a bunch of these under different names. The one I bought is no longer on the site.)

I also have a ReFlowR programmable soldering hotplate that I've never actually used. Maybe someday I'll find an actual need for the thing. Not worth posting a link, it's no longer being made.

73,
Gwen, NG3P


William Jenrick
 

Hot air station(?). Wow! Things have really got HI-tec in the last 60 years since I first got my general class license at age 15.  Do the math, I am 75.
Just now getting back into ham radio for something to do since I retired and am looking forward to renewing my morse code skills. I still have my gold plated Vibroplex bug from 60 years ago, but went ahead and bought a paddle since it appears the way to go nowadays....Nothing sacred anymore(?)....

On Wed, Feb 24, 2021 at 10:16 PM Gwen Patton <ardrhi@...> wrote:
I splurged and got myself a hot air station. They aren't tremendously expensive. I think I paid about $65 for mine.

When doing SMT work, I have either an iExtruder solder paste dispenser or a tiny manual dispenser I got from Tindie. Then I use syringe-able solder paste and apply to the pads, carefully put the chip onto the pads with a pair of tweezers (I use a lighted magnifier or a LCD microscope), and heat it with the hot air station. When the solder melts, surface tension will practically SUCK the chip into alignment. Let cool, then clean off the flux that was in the solder paste with isopropyl and a swab. I use disposable foam swabs for electronics work, as they don't leave little wisps of cotton fiber everywhere. They get torn up on the board, but don't leave bits for the most part.

If you get a hot air station, removing a chip is easy. Apply some flux (I use Amtech NC-559-V2-TF Tacky Flux in a syringe), then heat the part while holding it with tweezers. When the solder melts, lift the chip off. Then clean up the pads with solder wick and your iron, and clean the board. Then you can apply fresh solder paste to the pads, and hot air solder the new chip in place.

I get the tacky flux from Rossmann Group in New York, a certified Amtech dealer. It's really good flux. I mostly use that for soldering iron work. https://store.rossmanngroup.com/amtech-nc-559-v2-30-cc-16160.html
I get either MG Chemicals T3 solder paste for larger pads, or Chip Quik T5 solder paste for really tiny pads. The really small syringe applicator I have is for the T5. When working with paste, that number matters. The smaller the number, the larger a syringe needle you need for it to flow properly.

https://www.i-extruder.com/en/
https://www.tindie.com/products/avandalen/disper-micro-dot-solder-paste-syringe-dispenser/
Chip Quik T5: https://www.amazon.com/gp/product/B00D2I88PG/
MG T3: https://www.amazon.com/gp/product/B00M1RC0YY

I have 3 soldering irons. A TS-100 with an ILS tip  for fine work, a cheap but temp controlled mains iron from Banggood for connectors, PCB enclosures, and large heat sinks, and a Dremel Versa-Tip butane iron for outdoor work.

TS100: https://www.amazon.com/gp/product/B06XBFTKMY
ILS Tip: https://www.amazon.com/gp/product/B072J75BRT/
https://www.banggood.com/MUSTOOL-MT883-80W-Electric-Solder-Iron-Station-Adjustable-Temperature-180-480-or-392-896-Auto-Sleeping-110V-or-220V-EU-or-US-or-UK-Plug-Option-p-1553736.html
WEP/Kohree Hot Air Station: https://www.amazon.com/Kohree-Rework-Station-Solder-Digital/dp/B00JVM3WBC  (There's a bunch of these under different names. The one I bought is no longer on the site.)

I also have a ReFlowR programmable soldering hotplate that I've never actually used. Maybe someday I'll find an actual need for the thing. Not worth posting a link, it's no longer being made.

73,
Gwen, NG3P



--
William Jenrick 


William Jenrick
 

Yes, I bought 5 of them for $.89/each but really don't know which is pin 1. The original one has a dot. So how does that correspond to the one pictured?

On Wed, Feb 24, 2021 at 9:50 PM Hans Summers <hans.summers@...> wrote:
Hi all

Another reminder, just in case it helps anyone: when replacing an Si5351A chip please be sure to purchase Si5351A-B-GT or Si5351A-B-GTR (Matt's appears to be correct). Do not be tempted to buy a part number such as Si5351A-Bxxxxx-GT [R] because the xxxxx indicates it is a customized chip for a particular customer's requirements; these typically operate on I2C bus addresses other than 0x60. These non-standard chips will NOT work in QRP Labs kits. 

73 Hans G0UPL
http://qrp-labs.com

On Thu, Feb 25, 2021 at 8:03 AM Matt Burge via groups.io <matt24512=yahoo.com@groups.io> wrote:
Hi William, i am about to... i have a new chip and i intend to use solder paste & a heat gun... i have purchased an SMD practice board.. i was going to just use the soldering iron method 
but that chip is sooooo dam tiny... its costing a little more to get the equipment together but i am enjoying the challenge.. lol I overheated my chip while searching for another fault to do with the controls board.. good luck 👍



--
William Jenrick 


Ian VA7ITM
 

when replacing an Si5351A chip please be sure to purchase Si5351A-B-GT or Si5351A-B-GTR. Do not be tempted to buy a part number such as Si5351A-Bxxxxx-GT [R]
Wait... what?! C**p! Well that explains everything. Problem now is that in North America Digikey, Mouser, Arrow, RS, etc have no stock and a lead time of 20+ weeks! The one unofficial supplier that I did find was charging $18 for delivery...

... and alas the SI5351A is not available from QRP Labs shop either.

There's a lesson to be learned here... if you frazzle your Mini don't even bother trying to repair the SMD devices. By the time you've bought new SMD devices, paid for shipping and spent $20 on ChipQuik, you could have bought a new QCX mini main board with all components from QRP Labs for only $40!!


William Jenrick
 

Yea, but then if I buy another QCX kit and wind the "TOROID FROM HELL" and the chip fails again, then where am I.....? Besides It is not the mini I have, but the maxi....

On Wed, Feb 24, 2021 at 11:27 PM Ian VA7ITM <ian.mcalpine@...> wrote:
when replacing an Si5351A chip please be sure to purchase Si5351A-B-GT or Si5351A-B-GTR. Do not be tempted to buy a part number such as Si5351A-Bxxxxx-GT [R]
Wait... what?! C**p! Well that explains everything. Problem now is that in North America Digikey, Mouser, Arrow, RS, etc have no stock and a lead time of 20+ weeks! The one unofficial supplier that I did find was charging $18 for delivery...

... and alas the SI5351A is not available from QRP Labs shop either.

There's a lesson to be learned here... if you frazzle your Mini don't even bother trying to repair the SMD devices. By the time you've bought new SMD devices, paid for shipping and spent $20 on ChipQuik, you could have bought a new QCX mini main board with all components from QRP Labs for only $40!!



--
William Jenrick