English Amiga Board - View Single Post

Lektroid · 15 August 2020, 12:53

I'm no expert, but no spring chicken. I have been working in electronics since the late '80s, my contracts included avionocs (aircraft communication systems), electronics for the digital TV infrastructure in the UK, not to mention being a test engineer at Commodore in Peterborough. Happy to share a couple of tips, someone may find them useful.

I have a couple of Weller irons on my bench, it's good to have two irons when removing 2 contact SMDs, a soldering iron at either side of the component will quickly lift the part off. Removing anything bigger than 2-pin parts, use a hot air rework station, they're pretty useless for soldering, but great for multi pin part removal - including 40 pin through hole ICs. I also have a TS80 for field work away from the bench. If you don't have a low voltage iron like the TS80/100 (which I would highly recommend), Always use a station (never a direct to mains), not only for a well regulated temperature, but reduced voltage leak at the tip.

You should never need to go over 350ºC on any board, if you do, you run the risk of lifting pads/traces. If you find you need to go over, your iron has poor heat transfer efficiency, this can also be down to poorly maintained tips. Tip life can be hugely extended with auto standby on your iron which drops the temperature when not in use (in case like me you are forgetful and often leave your iron on).

One thing I notice is folk talking about the fumes from lead solder, firstly there is no way on this planet you'll be able to reach the temperature required for lead to evaporate with a any sort of off the shelf soldering iron, the toxicity comes from the rosin flux. That said, liquid flux is great for tidy factory finish joints, and essential for tight pitch SMD ICs, but can make the PCB sticky, so have some isopropyl on hand.

Always use lead solder (60/40 or 63/37) when repairing or reconditioning older machines like the Amiga, C64 etc. (I also do a lot of vintage synth repairs). It's very rare for pre-RoHS units to use lead free solder, and the two types do not mix well and have different melting points (lead free is usually higher and thus you run the risk of messing your board up.

These are just a few tips off the top of my head, but if I think of anything else, I'll post it here, hopefully you'll find something of use if it's not already been mentioned (I've not read the whole thread).

15 August 2020, 12:53	#253
Lektroid Registered User Join Date: Aug 2020 Location: UK Posts: 122	I'm no expert, but no spring chicken. I have been working in electronics since the late '80s, my contracts included avionocs (aircraft communication systems), electronics for the digital TV infrastructure in the UK, not to mention being a test engineer at Commodore in Peterborough. Happy to share a couple of tips, someone may find them useful. I have a couple of Weller irons on my bench, it's good to have two irons when removing 2 contact SMDs, a soldering iron at either side of the component will quickly lift the part off. Removing anything bigger than 2-pin parts, use a hot air rework station, they're pretty useless for soldering, but great for multi pin part removal - including 40 pin through hole ICs. I also have a TS80 for field work away from the bench. If you don't have a low voltage iron like the TS80/100 (which I would highly recommend), Always use a station (never a direct to mains), not only for a well regulated temperature, but reduced voltage leak at the tip. You should never need to go over 350ºC on any board, if you do, you run the risk of lifting pads/traces. If you find you need to go over, your iron has poor heat transfer efficiency, this can also be down to poorly maintained tips. Tip life can be hugely extended with auto standby on your iron which drops the temperature when not in use (in case like me you are forgetful and often leave your iron on). One thing I notice is folk talking about the fumes from lead solder, firstly there is no way on this planet you'll be able to reach the temperature required for lead to evaporate with a any sort of off the shelf soldering iron, the toxicity comes from the rosin flux. That said, liquid flux is great for tidy factory finish joints, and essential for tight pitch SMD ICs, but can make the PCB sticky, so have some isopropyl on hand. Always use lead solder (60/40 or 63/37) when repairing or reconditioning older machines like the Amiga, C64 etc. (I also do a lot of vintage synth repairs). It's very rare for pre-RoHS units to use lead free solder, and the two types do not mix well and have different melting points (lead free is usually higher and thus you run the risk of messing your board up. These are just a few tips off the top of my head, but if I think of anything else, I'll post it here, hopefully you'll find something of use if it's not already been mentioned (I've not read the whole thread). Last edited by Lektroid; 16 August 2020 at 21:39.