HP Forum Archive 19

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Classic Series Logic Board - Desoldering Temp ? Message #1 Posted by John Robinson on 17 Sept 2009, 8:29 a.m. 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

Re: Classic Series Logic Board - Desoldering Temp ? Message #2 Posted by Randy on 17 Sept 2009, 9:12 a.m., in response to message #1 by John Robinson Never needed more than 310 C. Perhaps you're just out of calibration?

Re: Classic Series Logic Board - Desoldering Temp ? Message #3 Posted by Joel Setton (France) on 17 Sept 2009, 10:25 a.m., in response to message #2 by Randy 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

Re: Classic Series Logic Board - Desoldering Temp ? Message #4 Posted by Dan W on 17 Sept 2009, 1:52 p.m., in response to message #1 by John Robinson 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. ;)

Re: Classic Series Logic Board - Desoldering Temp ? Message #5 Posted by Martin Pinckney on 17 Sept 2009, 2:52 p.m., in response to message #4 by Dan W Quote: F to C conversion thanks to my handy HP-55. 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.

Re: Classic Series Logic Board - Desoldering Temp ? Message #6 Posted by Dan W on 17 Sept 2009, 3:49 p.m., in response to message #5 by Martin Pinckney Quote: 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. 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.

Re: Classic Series Logic Board - Desoldering Temp ? Message #7 Posted by John Robinson on 17 Sept 2009, 8:02 p.m., in response to message #1 by 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

Re: Classic Series Logic Board - Desoldering Temp ? Message #8 Posted by Dan W on 17 Sept 2009, 9:36 p.m., in response to message #7 by John Robinson 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

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