Thread: Fanuc OM-C Dead RS232 port... Repair, new, or???

Cool man, I'm glad that was of some use.

Originally Posted by Miketd

A solder sucker is a nice thing to have when you're doing this so you can clear out the PCB holes and make room for the socket you're putting in.

DP-140 OK Industries/Div of Jonard Ind Corp | K500-ND | DigiKey

That will do for a few but if you ever find yourself having to desolder alot of IC legs, something like a Hakko 472 with electric vacuum pump is infinitely better. Important to have as small a tip as possible for the leg size and keep it clear with their special tool. I once desoldered 20 IC's with 20 legs each on one board...that's 400 desolder cycles. All in very tight quarters and keeping each IC intact (i.e. no leg cutting) so I could test each one. Didn't use any solder wick...didn't need it.

I only flowed the solder onto the socket pins from the bottom side of the board. I put a small amount down as I am worried about flowing off the pad and into a trace. Maybe I should solder from the top too or let it flow a bit longer.

Bottom only is the way it's done...there should be metal eyelets that connect bottom pad to top of PCB pad. Check continuity with multimeter to test any suspect solder areas, check continuity direct from pad to IC leg if possible, as it is possible to fold over an IC leg as you insert it in a socket and not know it, if it folds over to the inside.

Originally Posted by Milacron

That will do for a few but if you ever find yourself having to desolder alot of IC legs, something like a Hakko 472 with electric vacuum pump is infinitely better. Important to have as small a tip as possible for the leg size and keep it clear with their special tool. I once desoldered 20 IC's with 20 legs each on one board...that's 400 desolder cycles. All in very tight quarters and keeping each IC intact (i.e. no leg cutting) so I could test each one. Didn't use any solder wick...didn't need it..

Milacron,
I bought a Hakko 880 kit for this job, and had limited success with desoldering. I think my method was wrong, not the tool. I clipped all the legs then heated and removed them, leaving a small amount of solder in the holes. It seemed the holes that had more material in them, the Hakko worked a treat on. The ones that were shallow, seemed to not heat and flow. I tried desoldering with the legs still in the hole after the fact and that seemed to work on my sacrificial practice board. Maybe I needed a smaller tip too. I have another board to fix on the bostomatic, yet. Might be good to practice before going head long into it.

BTW I fixed the old mori lathe. Replacing the power supply fuses and the MDI/CRT board cured it. I found a MDI/CRT board on ebay for $500, plus shipping and fuses a little over $600 for its fix.

Originally Posted by GBeaman

Milacron,
I bought a Hakko 880 kit for this job, and had limited success with desoldering. I think my method was wrong, not the tool. I clipped all the legs then heated and removed them, leaving a small amount of solder in the holes. It seemed the holes that had more material in them, the Hakko worked a treat on. The ones that were shallow, seemed to not heat and flow. I tried desoldering with the legs still in the hole after the fact and that seemed to work on my sacrificial practice board. Maybe I needed a smaller tip too. I have another board to fix on the bostomatic, yet. Might be good to practice before going head long into it.

I use an A1002 tip, which may be the smallest one they offer. Makes a huge difference in getting nearly all the solder out around an IC leg. But still there will be a tiny residue...the technique is to move leg back and forth a bit while sucking, finish sucking with leg toward outside of hole, then push leg opposite direction to break it free with no heat (or minimal amount...not enough to remelt solder nearby).

As I said, I wanted my IC's intact so I could test them...but once you get the hang of it, it's really faster to desolder with IC intact anyway...far as I'm concerned the leg cut technique is for amatures, or folks without proper desoldering equipment.

Originally Posted by GBeaman

Milacron,
I bought a Hakko 880 kit for this job, and had limited success with desoldering. I think my method was wrong, not the tool.

I was assuming until now a Hakko 880 was a newer version of my vacuum pump desoldering system, but I see now that it is apparently a heat gun meant for removing surface mount components. Below is a video link that shows IC desolder technique with vacuum. Although his example is easy as falling off a log... I could only dream of having that much space around my IC's...but nonetheless gives some idea of the technique involved.

Flat lead desoldering | Soldering Tips | B.E.S.T. - YouTube



IC's in the middle of this board are the sort of challenge I had to deal with... www.practicalmachinist.com/board2.jpg Even the little yellow caps had to be removed in order to have a leverage point to gently pry up the IC's.

Thanks for the video. I understand now how wiggling the leg back and forth a bit frees it from the board. I must apologize about my dyslexic moment, however. I should have written "Hakko 808" which has a vacuum pump built into the gun itself. Your unit would be handier with the pump separate from the hand held unit.

I am sorry for the confusion. I could edit my post, but it would make the thread not make sense to someone else later.
-Greg

Here is a picture of the unit I have to clarify.

Originally Posted by GBeaman

Thanks for the video. I understand now how wiggling the leg back and forth a bit frees it from the board. I must apologize about my dyslexic moment, however. I should have written "Hakko 808" which has a vacuum pump built into the gun itself. Your unit would be handier with the pump separate from the hand held unit.

Ah...that does make more sense. I have some desolder guns like that I bought at auction years ago. Some people swear by them but to me for the most difficult tight quarters and small pins desoldering, the separate units are more desirable, due to being lighter weight and smaller, easier to pinpoint control. Held like a pencil rather than a gun.