Adding fresh solder adds flux assuming you are using a flux core solder. While the carrier will vaporize, the flux solids remain. I always deflux when the repair is completed.
Not sure either, but I often use hot air to preheat the area before using the iron. Nothing ruins desoldering faster than heat sinking.
And nothing ruins germanium semis faster than NOT heat sinking.
Not sure of your point, but what I'm referring to is the heat sink action o f a multi layer PC with a huge ground plane running on or in it. Placing a soldering tip on some points can actually freeze the tip to the joint in w orse cases, or prevent complete solder melting inside a plated through hole . Anybody who has replaced an IPM on an LG sustain board can attest to thi s. Preheating the board minimizes excessive loss of desoldering tip heat to surrounding areas.
Right, you make the desoldering iron tip push the pin in a circular movement while the suction is operating. This is the technique described in the Pace manual, and it REALLY works!
Well, I rework some prety expensive boards for physics research gear. One thing I've done a lot of is recovering $10 connectors with 68 pins. The problem is not the cost of ONE connector, but the distributors make you buy
160 pieces minimum order! That does get expensive. We have piles of old boards that have been superseded with newer designs. I can desolder the connectors in about 10 minutes with the Pace. The boards would be usable if we wanted to do that, but the evidence of the desoldering would be visible. I'd hate to try doing a 68-pin connector with a spring-piston solder puller.Jon
The early Japanese radios had the transistors mounted almost flush - I wonder how they got shunts onto those tiny short leads?
Years ago I got the compressor from a scrap fridge, coiled up the pipe and wedged it in the grille of a portable LPG heater with a carburettor jet peened into the end.
It worked well harvesting from all SMD boards, but I was getting toasted using it.
...
Yeah, I would not attempt something like those 68-pin or ICs with the tiny pins, etc. with the Soldapullt.
When it gets down to it we use five basic methods of desoldering devices in the order of use on my bench:
1) Weller and Soldapullt2) Pace desoldering station
3) Weller and solder wick4) Weller and Chip-Quik surface mount desolder kit. This has an alloy rod that greatly reduces the melting point of the solder and is used on very fragile items and small surface mount repairs.
5) Hot Lamp surface mount station (we really get very little surface mount work).John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
I've used the propane (using MAPP gas tank) torch method on boards that are to be scrapped - heat the bottom side of the board fast and very hot, bang the board (IC legs down) onto a piece of wood to drive the molten solder off the bottom, then retrieve the released parts.
Makes a mess of the PCB, but the ICs are usually fine. At least it is quick!
John ;-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
make you buy 160 pieces minimum order! That does get expensive.
As a private individual repairing my own kit I have met that problem too. If you can find a sympathetic salesperson you could try asking for a "sample"...
Mike.
Some of that has aslways been a sore spot with me. The companies should be required to sell any parts to an individual to do their own repair. I went with a man to help him pick up some boat motor parts. A man off the street wanted to buy some small part of about $ 20. They would not sell it to him. So we bought the part and then sold it to him. If not for us, he would have had a hard time getting that part.
I have called some companies and received small parts with no problem. Needed a special transistor for a $ 1500 radio. Called Icom and ordered two of them and the postage and parts was about $ 5. No rip off at all from them.
I once needed some microwave transistors from Rockwell-Collins. They wanted $1500 each, and I had to buy 15 of them. The deliver date was almost a year away. Needless to say, I scrapped a lot of their $4,000 radios. I replaced them with new Microdyne 1100LPR receivers for under $1200 each. The new units were agile, with a digital tuner. The older $4,000 units were tunable, but they needed an input filter for whatever frequency you needed. We had a lot higher quality signal from the new equipment, and it ran a lot cooler. :)
I can confirm this method works beautifully. It feels like a waste of time 'testing' each pin, but being able to lift the IC out undamaged and the pins straight with fingertips makes it worth it, especially if you're trying to save the IC. It also prevents pulling out the plating 'tube' with plated-through holes. My heart always sank when that happened.
--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")
As long as the pads on both sides have tracks, its fairly easy to repair with a strand of wire - unless its a multilayer board with internal connections to that via!
Yes, or make sure the pin is soldered both top and bottom.
If that happens, it's sayonara, I think.
--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")
I had a Samsung multi layer board that was working but quit after I replace d a typical leaded electrolytic that was vented a bit. Top and bottom conn ections fine but the middle layer was not. Several reheats did not fix it.
Fortunately I had a working board and I used a DMM on the diode scale (for the audible) and attached one lead to the cap in question and I waltzed the other lead around the board on every point until I found a zero ohm connec tion that did not exist on the damaged board. Running an external jumper f ixed it.
Ingenious. I'll remember that. Thanks.
--
(\_/)
(='.'=) Bunny says: Windows 10? Nein danke!
(")_(")
Well, you got lucky. You'd want to find the closest point that same net came to another through-hole. If that net didn't come out to another hole nearby, the long wire would somewhat defeat the purpose of the cap. If in a high frequency circuit like a switching regulator, it might not work.
Jon
Wow, fair pricing and avialable parts? Glad I just got an Icom radio. Just tore it apart too- the construction is excellent- reminds me of late 1990s Motorola radios in the attention to detail and ease of service.
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.