Classic Series Logic Board - Desoldering Temp ?

[John Robinson]

Hi, can anyone recommend the best temperature to set a desoldering iron at for removing components from classic series logic boards ? I am finding that I need 400 Celcius but that sounds a little high to me.

Thanks
John

[Randy]

Never needed more than 310 C. Perhaps you're just out of calibration?

[Joel Setton (France)]

The Classics were manufactured with tin-lead solder alloys (way before the age of lead-free soldering!) which have a low melting point. Start with lower temperatures first, like 290 or 300C which should be OK. Be very careful, as the 5-digit LED displays are VERY sensitive to heat!

I hope this helps,

Joel Setton

[Dan W]

I typically use about 600-650F (315-340C) when soldering, which is probably higher than needed. I highly recommend a desoldering gun such as a Hakko 880 when desoldering the chips. The heat is applied only for about 2 seconds each connection and it's clean enough to fall right out.

F to C conversion thanks to my handy HP-55. Now if I could just find some use for the timer. ;)

[Martin Pinckney]

Quote:

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F to C conversion thanks to my handy HP-55.

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Interesting. I hadn't realized unit conversions (English-Metric, that is) had been built in to calculators that early. Looking at the HP-55 features, I was surprised to learn that it included BTU-Joules and LBF-Newtons, whereas most calcs lesser than say, the 28 series, limit themselves to length, mass, volume, and temperature, and only one of each of the aforementioned.

[Dan W]

Quote:

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Interesting. I hadn't realized unit conversions (English-Metric, that is) had been built in to calculators that early. Looking at the HP-55 features, I was surprised to learn that it included BTU-Joules and LBF-Newtons, whereas most calcs lesser than say, the 28 series, limit themselves to length, mass, volume, and temperature, and only one of each of the aforementioned.

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The HP-45 also had a few conversions: cm/in, kg/lb, ltr/gal. But in this case it offered the conversion factors only, one still had to multiply or divide appropriately. The 55 did the math at the push of the button.

[John Robinson]

Thanks for the feedback all !! Might be a calibration issue.

Dan, my Hakko 808 "chinese clone" has a minimum temp of 350, but I think the Hakko has a minimum of 380 - is that what you use ?

Thanks
John

[Dan W]

Hi John,

Ah! Now I know who you are - wasn't paying attention.

Anyway I am using whatever the default is from the factory. I haven't tried to measure it.

-- Dan