Am i killing my resistors?

Gmorb

Member
ive been having a little trouble lately. i thought it was my donor board resistors being bad but its probably just my technique. everytime i replace a resistor with a known good the readings are always off either too low or way too high. what am i doing wrong? am i heating them up too much? what is your guys' technique for smd soldering. how many degrees? I am using the quick 861dw station and around 330 degrees i find this amount easy to replace smd resistors fast but may be killing them. i tried lower settings but solder takes too long to heat up.

any guidance or tips appreciated.
 

smiba

New member
Damaging a resistor is very hard, unless you abuse them there shoudn't be a reason for them to go way out of spec.

You can use higher temperatures like 400 degrees without issues, just be nice to the board by pre-heating from a distance for ~10 seconds and slowly move closer to the object you want to (de)solder. You can even be a bit rougher on dead components that you want to remove as well.

How much are they going out of spec? Up to 5% is alright and to be expected when the resistors are still at a high temperature, if they're still very hot they might even be totally out of spec because they're not meant to be used above 100C
Also resistors very rarely go lower then what they're meant to be, you're probably seeing other parts in that circuit lowering the resistance.
 
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dukefawks

Administrator
Measuring them in circuit will usually throw off the reading in the lower direction. Also residual charge could result in measurements being off even in the up direction. Make sure the circuit is fully discharged.
 
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