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#372574 - 02/02/2020 20:52 Hot air desoldering tool
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
In addition to empeg players, I also sometimes repair automotive ECUs (Engine Control Unit, aka "the car's computer").

Usually it's just a matter of somehow opening up the factory sealed enclosure (if possible) and then looking for obviously fried components. Replace the baddies and eight times out of ten it works again.

The current one I'm looking at had an obvious failure point, in a 20-pin driver chip (CAD$8 from Digikey.ca). But getting it off the board was a real tug of war. In the end I just cut it into pieces, and pried those off to reveal the solid copper heatsink base of the chip, soldered to a very large pad on the board under the chip.

The soldering iron was inadequate for removal, so I applied heat from a small butane torch directly to the copper remnant of the chip, and it came away cleanly.

Obviously I cannot rely on the same method for reattachment, so I'm finally getting a hot-air (de-)soldering gun. Essentially a small heat gun with temperature and airflow controls.

I don't have it yet, but this is what I ordered:
https://www.amazon.ca/gp/product/B07FBGFT3K/

There were several similar models, with various inclusions and exclusions, but I chose that one for the digital display and the calibration button, which should allow better temperature accuracy in conjunction with my multimeter and a temperature probe. There were other models ranging from around $25 upwards.

Anyone else here have experience with these things? Tips and advice welcome!



Attachments
ecu1.jpg

Description: Spot the blown chip!

ecu2.jpg

Description: Removed. With fuss.



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#372575 - 03/02/2020 02:03 Re: Hot air desoldering tool [Re: mlord]
tanstaafl.
carpal tunnel

Registered: 08/07/1999
Posts: 5539
Loc: Ajijic, Mexico
Originally Posted By: mlord
Tips and advice welcome!

I would recommend that you read carefully the one-star review for this product. There's only one of them, but it is... interesting.

tanstaafl.
_________________________
"There Ain't No Such Thing As A Free Lunch"

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#372576 - 03/02/2020 14:15 Re: Hot air desoldering tool [Re: mlord]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
I read that review, thanks. A Factory assembly error on the power wiring, easily checked for. The rest of the review was very much at odds with all of the others, so perhaps a total lemon unit there.

Pretty much everything on Amazon has one or more such reviews, as well as dozens (or more) fake positive reviews.

Cheers

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#372577 - 03/02/2020 17:57 Re: Hot air desoldering tool [Re: mlord]
tanstaafl.
carpal tunnel

Registered: 08/07/1999
Posts: 5539
Loc: Ajijic, Mexico
Originally Posted By: mlord
...as well as dozens (or more) fake positive reviews
That is why I only read the one and two star reviews! I figure if three or four people press the same hot button and it is one of my hot buttons as well, that's enough for me.

tanstaafl.
_________________________
"There Ain't No Such Thing As A Free Lunch"

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#372587 - 06/02/2020 13:33 Re: Hot air desoldering tool [Re: mlord]
mlord
carpal tunnel

Registered: 29/08/2000
Posts: 14472
Loc: Canada
The hot air tool arrived on Tuesday, and sure enough, the included "IEC" power cord was incorrectly wired. The load/neutral wires were reversed within the power cord, yet the actual hot air device is wired correctly.

So I cut up and tossed the power cord, and just grabbed another from my stash. Even with the faulty power cord, there didn't seem to be any immediate danger though. The neutral inside the unit was (correctly) not attached to anything external, so no obvious shock hazard. But I have cut/tossed the faulty cord regardless.

The hot air tool works quite well, and had no issues at all in soldering down the replacement chip in the ECU I was working on. That board is now back with the mechanics, though I have yet to hear whether the repair was sufficient to bring the host vehicle back to life. smile

Decent hot air tool for CAD$72. With an extra (spare) heating element included for when the original someday burns out, as well as various tweezers and solder pick tools etc included. I did also (separately) purchase a larger assortment of tips for use with the tool, and those fit it without issues.

In all, a nice addition to the kit here, and I could really have used one many times over the years of repairing empegs, cellphones, and other gear. Happy to finally get there now though!

Cheers

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#372588 - 06/02/2020 18:12 Re: Hot air desoldering tool [Re: mlord]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31563
Loc: Seattle, WA
Originally Posted By: mlord
Pretty much everything on Amazon has one or more such reviews, as well as dozens (or more) fake positive reviews.


Diverging from the topic, but... I've been happy with this Chrome plugin to help tell me whether the Amazon reviews for a product are fake or not:

Fakespot - Analyze Fake Amazon Reviews
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Tony Fabris

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#372594 - 07/02/2020 21:36 Re: Hot air desoldering tool [Re: tfabris]
Dignan
carpal tunnel

Registered: 08/03/2000
Posts: 12318
Loc: Sterling, VA
Originally Posted By: tfabris
Originally Posted By: mlord
Pretty much everything on Amazon has one or more such reviews, as well as dozens (or more) fake positive reviews.


Diverging from the topic, but... I've been happy with this Chrome plugin to help tell me whether the Amazon reviews for a product are fake or not:

Fakespot - Analyze Fake Amazon Reviews

Interesting. I'll try it out. So far, apparently all the reviews of the Unifi products that I love are pretty lowly rated laugh
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Matt

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