maybe a job for my 100w iron ?

[petehall347]

just had a thought and wondered if my 100w iron would heat an as15 ic enough to remove it ? the bloody thing is surrounded by tiny components that i would rather stay put .

[redwire]

Re: maybe a job for my 100w iron ?

What's an "as15 ic" ? What package is it

[petehall347]

Re: maybe a job for my 100w iron ?

What's an "as15 ic" ? What package is it

i believe it is a QFP48

[diif]

Re: maybe a job for my 100w iron ?

I'd thing it depends how good the thermal transfer is of the iron tip to ic, I can't see it doing any damage to the board.

[petehall347]

Re: maybe a job for my 100w iron ?

think i will try on an old board if i can find one . the iron has a large tip .i use it for repairing alternators and starter motors .

[stj]

Re: maybe a job for my 100w iron ?

so why not use hot air?

[petehall347]

Re: maybe a job for my 100w iron ?

so why not use hot air?

not had much luck with hot air as yet . plus i would like to avoid disturbing the minuscule sized components surrounding the ic .

[sam_sam_sam]

Re: maybe a job for my 100w iron ?

It might be that you do not have the right tip for your hot air gun

For what I use mine for is removing IGBT module pins from a circuit board I use the smallest round tube at maximum air flow to do this job so I do not trae off traces on either side of the board with a Desoldering Gun
( and other two sided boards with ground planes )

Try putting foil around everything that is not suppose to be removed

One note to this is a pain in a** to rework this type of application boards
One other note when using very small tip opening you have to have the air flow higher otherwise you might burn out the element

[diif]

Re: maybe a job for my 100w iron ?

They won't move unless you touch them, or the air speed is way too high.

[stj]

Re: maybe a job for my 100w iron ?

yes, too much airflow - dont be a Rossmann!

[redwire]

Re: maybe a job for my 100w iron ?

It's tough because you have to heat up all pins on all four sides. If you heat up only one or two edges, total waste of time.

Another approach I have used is cut the IC's pins off with an Exacto knife. Not too hard to trash the pcb. Then I use solder wick to clean up the pin fragments and clean off the pads.

The small nozzle is bad on my 858D, it's pretty much choked off so much the thermocouple doesn't get enough hot air inside. During warm up it massively overshoots and I can smell burnt plastic, so I first warm it up with a bigger nozzle. The cold heater ceramic seems to keep the thermocouple cold longer than the air is hot.

[stj]

Re: maybe a job for my 100w iron ?

set your temp to 360, and airflow to 2.5 and use an 8-10mm nozzle in a circular pattern

[petehall347]

Re: maybe a job for my 100w iron ?

2.5 ..mmm will have to go look to see the graduation . and the nozzles

[petehall347]

Re: maybe a job for my 100w iron ?

ok just tried another board . similar pinned chip but a bit bigger . carried on until my back was hurting ,maybe 5 mins . no melted solder .could burn my finger on the ic . oh the airflow goes to number 8 .

[petehall347]

Re: maybe a job for my 100w iron ?

well i got the bugger off with heat gun but had to set at 400 . lifted 2 traces but should be ok . was impatient and started lifting it before it was ready ..my back hurts after a few minutes .

[stj]

Re: maybe a job for my 100w iron ?

i forgot to mention, the nozzle is about 3cm from the target

[petehall347]

Re: maybe a job for my 100w iron ?

i had it closer than that .

[petehall347]

Re: maybe a job for my 100w iron ?

well i didn't even plug in my big iron and the job is done . had to solder the chip twice because it wasn't right first time . i did my old trick of lightly flooding the pins then using the solder sucker to remove the excess . pic was washed out looking so did a picture reset and looking good now .just needs tweaking when i get a remote for it .

[BadmanRasta]

Re: maybe a job for my 100w iron ?

not had much luck with hot air as yet . plus i would like to avoid disturbing the minuscule sized components surrounding the ic .

What was wrong with using hot air? I'm considering this approach but I want to find out about potential issues

[stj]

Re: maybe a job for my 100w iron ?

if your airflow is too high you blow all the 0402 and smaller caps/resistors off the board!!!