Hello, I got now one of those T34 plugs. This belongs to those devices where MCU sits totally on any pads to solder wires. So - I suppose, it has to be desoldered and flashed loose. But how much heat does it tolerate? I don't have proper gear to do it. Do I fry the MCU if I just put heat on it...

How do you want to desolder T34 (QFN or similar) without hot air? I don't think it's reasonably possible. It even has 4 pads under itself. See:

Yes. There is those pads. And yes. Unfortunately I do not have proper heatgun to do it. I suppose hot air does also heat the whole chip. I suppose it does hold that temperature even though it is quite much for this kind of chips. So you think it's not worth trying? Actually I'm trying to update Cloudcutter to see if it can do miracles.

I used a 'JCD Hot Air Gun 8858A Micro Rework Soldering Station' which I bought from a well known Chinese Warehouse. Temperature was set to 410C°. I took about 90 seconds applying the heat until I could gently lift the T34. I protected the parts around the T34 from heat with Kapton tape. There are many examples on YouTube of how to desolder QFN components safely.

Hey, T34 is not BGA. It's QFN. 858 is a good cheap hot air. You can check my tests of multiple stations to see which performs best. Avoid the ones that can't reach target temperature.

Maximum Safe Temperature for Desoldering T34 Plug MCU Without Damage

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#1 21723803 18 Oct 2025 11:28

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21723803 18 Oct 2025 11:28

Hello,

I got now one of those T34 plugs. This belongs to those devices where MCU sits totally on any pads to solder wires.

So - I suppose, it has to be desoldered and flashed loose. But how much heat does it tolerate? I don't have proper gear to do it. Do I fry the MCU if I just put heat on it by regular soldering iron?
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#2 21723846 18 Oct 2025 12:28

p.kaczmarek2 p.kaczmarek2

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21723846 18 Oct 2025 12:28

How do you want to desolder T34 (QFN or similar) without hot air? I don't think it's reasonably possible. It even has 4 pads under itself. See: https://www.elektroda.com/rtvforum/topic4110013.html
p.kaczmarek2 wrote:

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

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#3 21723868 18 Oct 2025 12:50

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21723868 18 Oct 2025 12:50

Yes. There is those pads. And yes. Unfortunately I do not have proper heatgun to do it.

I suppose hot air does also heat the whole chip. I suppose it does hold that temperature even though it is quite much for this kind of chips.

So you think it's not worth trying? Actually I'm trying to update Cloudcutter to see if it can do miracles.
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#4 21723885 18 Oct 2025 13:08

sp4rk1e sp4rk1e

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21723885 18 Oct 2025 13:08

I used a 'JCD Hot Air Gun 8858A Micro Rework Soldering Station' which I bought from a well known Chinese Warehouse. Temperature was set to 410C°. I took about 90 seconds applying the heat until I could gently lift the T34. I protected the parts around the T34 from heat with Kapton tape. There are many examples on YouTube of how to desolder QFN components safely.
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#5 21723893 18 Oct 2025 13:16

p.kaczmarek2 p.kaczmarek2

Moderator Smart Home

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Post #5
21723893 18 Oct 2025 13:16

Hey, T34 is not BGA. It's QFN.

858 is a good cheap hot air. You can check my tests of multiple stations to see which performs best. Avoid the ones that can't reach target temperature.
https://openshwprojects.github.io/hotair/350c.html
https://openshwprojects.github.io/hotair/450c.html

I am creating multiplatform open source firmware (Tasmota replacement), right now supporting BK7231T, BK7231N, XR809, BL602, W800, W600, LN882H and soon supporting RTL and W701:
https://github.com/openshwprojects/OpenBK7231T
If you like my work, support me at: https://paypal.me/openshwprojects

Helpful post? Buy me a coffee.
#6 21723901 18 Oct 2025 13:28

sp4rk1e sp4rk1e

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Post #6
21723901 18 Oct 2025 13:28

p.kaczmarek2 wrote:
Hey, T34 is not BGA. It's QFN.

sure I corrected this
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Maximum Safe Temperature for Desoldering T34 Plug MCU Without Damage

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