Desoldering with a Hakko 808 on a real old board. - Page 1
Forum section: electronics / beginners

author: UF8FF
author_rank: Contributor
timestamp: January 21, 2017, 09:54:07 pm
content: Hey everyone,I recently got lucky and nabbed a Hakko 808 from eBay for $129 and it has been great! To get some practice I took apart an old joystick and removed some of the buttons and capacitors on the boards and it worked like a dream. But the tides have turned!The reason I purchased this guy is to remove the CPU and PPU off of an original, front-loader Nintendo Entertainment system. I got a majority of the pins desoldered last night on the CPU except for maybe 4-5. When I look at the component side of the board it looks like there is still a little solder on that side connected to the pins and, as I'll show in a picture below, some of the solder almost isn't coming up at all. So I put flux down and resoldered those pins and a few come up and worked but I have two left that are being a real PITA. The one in the picture is the worst so far. I can see the solder melt but then it doesn't suck up! I did have a couple times last night where I had to cool down the gun and clear the heating element because solder was stuck in there. I have recently replaced the diaphragms but I did my best to make sure they were flat when I put the covers back on. I am thinking of cleaning the valves -- but maybe it's not a vacuum issue at all? Maybe it's just super old solder? I tried some copper wick but I'm not sure how successful I've been based on the photo.Any tips?Thanks for the help!

author: Sebzy
author_rank: Contributor
timestamp: January 21, 2017, 10:52:26 pm
content: In cases like this I have applied a good healthy blob of lead solder to the pin and gently but firmly pulled the component from the other side with needle nose pliers of chip puller.

author: mcinque
author_rank: Unknown
timestamp: January 21, 2017, 10:55:35 pm
content: Check the vacuum of the 808: when it's cold, close its tip hole with a finger and "hear" if the sound changes.Check the temperature of the 808, does it melt easily the tin?Eventually, use the trimmer on the handle gun to regulate the power of the heat. I've set mine to 2,5 but it depends on the life of the heating element. When the solder melts easily on the tip of the gun, you can retry.What tip do you have? Does fit correctly on the pin or its hole it's too big? You can loose suction. A too small hole prevents suction.Apply flux and resolder the pins.Preheat the 808 at least 4 mins and then apply its tip to the pin, melting the the solder. Try to not push the tip on the pcb. It should take no more than 2 seconds to have the solder melted.As soon its melted, apply circular movements to the pin to detach it from the plated hole. Continue to do the circular movement and suck the solder.https://youtu.be/e8KRPFOD1REhttps://youtu.be/ULWDrF-JEUkHope it helps

author: UF8FF
author_rank: Contributor
timestamp: January 21, 2017, 11:09:55 pm
content: Quote from: mcinque on January 21, 2017, 10:55:35 pmThanks! I'll make sure to try all these. I do know that the solder is melting, which seems to be good -- also I was using a .8 mm and now using 1mm. We will see if your other tips help. Thank you again.

author: BMack
author_rank: Regular Contributor
timestamp: January 22, 2017, 04:43:27 am
content: .Edit: NM, misread.

author: UF8FF
author_rank: Contributor
timestamp: January 22, 2017, 09:01:57 pm
content: Just an update for those following:I cleaned the valves and hot damn it's better with suction. I could actually hear the nozzle sucking after cleaning the valves so that helped. As of now I have tried refilling that leg and tried again with no luck but I'm using RadioShack silver bearing solder so I don't believe it has lead -- i have ordered new solder with 2% lead and will have that Wednesday.A couple things;The leg broke on the stubborn one. Now I know it broke only to the surface of the board. I think I had just bent it too much and it weakened the metal to the point of fragility. I think I'll be ok though, and if necessary I saw that some people actually add a little metal and solder it on if it really is that bad.Second, I'm not sure how much these things can take since it's my first time removing an EPROM; how much force will this thing take to pull off? Is it ok to put any force at all? Or should I just keep soldering and desoldering until it basically falls out?Thanks for all your help! Also, I'll include a photo of the broken leg and the component side of the board.

author: james_s
author_rank: Super Contributor
timestamp: January 22, 2017, 10:22:19 pm
content: You really should practice more on some junk boards before trying to work on irreplaceable vintage parts like that. I bought a Hakko 808 years ago and love it, I don't know how I ever survived without it. When I encounter a stubborn part, I often add a bit of fresh solder and then hold the gun on it for 5-10 seconds to make sure the solder is melted all the way up through the hole then pull the trigger. Sometimes I'll wiggle it around a little to keep the leg from sticking to the side of the hole.For practice, pick up some broken electronics, that's very easy to do these days. Take it apart and start desoldering the components. An added bonus is that you'll get a stock of potentially interesting parts to build other stuff with. When I was a broke teenager I got almost all of my parts this way, but not having decent equipment I usually desoldered them by heating the board with a heat gun and whacking it on the bench.

author: UF8FF
author_rank: Contributor
timestamp: January 22, 2017, 11:23:15 pm
content: Quote from: james_s on January 22, 2017, 10:22:19 pmYeah wiggling the leg on that one killed it! But it was simply because of how many time I tried.I did have some junk boards and desoldered a lot of capacitors but no EPROMs. I was desoldering on the junk boards so easily I figured it'd be a piece of cake! But no worries. The leg should fit as I'll be attaching it to an interposer with headers so worst case scenario I will need to bridge that leg with some wire. Bummer, but I got this board real cheap from a buddy so I'm not out more than $25; but it would've been better to do this to an old busted PC or something!

author: BradC
author_rank: Super Contributor
timestamp: January 22, 2017, 11:49:34 pm
content: 2% lead solder won't help you. You want 60/40 or something close.

author: UF8FF
author_rank: Contributor
timestamp: January 22, 2017, 11:50:08 pm
content: Quote from: BradC on January 22, 2017, 11:49:34 pmNoted, I'll go grab some today!

author: Vtile
author_rank: Super Contributor
timestamp: January 22, 2017, 11:53:19 pm
content: Quote from: BradC on January 22, 2017, 11:49:34 pmI were just typing this. Then there is also some solders that have extremely low melting point (less than 37/63 tin/lead), but I have no further knowledge if they do more harm than good.

author: UF8FF
author_rank: Contributor
timestamp: January 23, 2017, 12:02:21 am
content: Quote from: Vtile on January 22, 2017, 11:53:19 pmI just also found that I was reading it wrong and I ordered rosin core 2% and it's 63/37

author: BradC
author_rank: Super Contributor
timestamp: January 23, 2017, 12:57:54 am
content: On particularly stubborn pins it's worth several solder/desolder cycles without putting any mechanical strain on the pin to make sure the solder is fresh. I generally go for the heat-soak then wiggle *before* hitting the trigger, then continue wiggling while the trigger is down. Sometimes you just have to cut the chip out to save the board, but I can count on one hand the number of times I've done that.

author: UF8FF
author_rank: Contributor
timestamp: January 23, 2017, 01:17:07 am
content: Quote from: BradC on January 23, 2017, 12:57:54 amRight on I'll keep at it, you guys have all been a great help, happy I found this place!

author: bitseeker
author_rank: Super Contributor
timestamp: January 23, 2017, 02:24:17 am
content: Definitely give the tip a couple of seconds to melt the solder before hitting the vacuum, especially when a lot of solder has gone though the hole to the other side of the PCB. Once the pump starts up, the cold air will hit the solder and start solidifying it.The 63/37 solder should help a lot. For desoldering, 60/40 can be advantageous since it has a wider temperature range over which the solder will be flexible.If you have one remaining pin or two adjacent ones, you can add some solder and flux, then heat them with a solder iron to melt the solder. Once it's molten, pull the component out. Never pull components when the solder is solid or you'll break leads, damage traces, etc.

author: RobertHolcombe
author_rank: Frequent Contributor
timestamp: January 23, 2017, 04:14:31 am
content: mcinque touched on some good pointsI only skimmed through the thread so may have missed someone else mentioning the following;The lead you are having issues with is attached to a large trace - this is a high thermal mass and will sink most of the heat out of the 808 before the solder reaches melting temperature. You can assist the 808 by either pre-heating the entire board or using an additional iron to apply heat to the lead from the opposite side of the board before applying vacuum.

author: james_s
author_rank: Super Contributor
timestamp: January 23, 2017, 04:19:53 am
content: The real issue that tends to happen with this is double sided boards with plated through holes where there's a thick trace or ground plane connected to the pin you're trying to desolder. This is especially true when said trace is on the top of the board, it sucks away the heat so the solder through the hole or on the top doesn't melt. When you wiggle a pin, it only takes a very small movement, don't wiggle it so hard that you're flexing it.

author: bitseeker
author_rank: Super Contributor
timestamp: January 23, 2017, 04:27:06 am
content: Coincidentally, I just finished fixing a flashlight that no longer wanted to light. It had a bad connection at a rivet in the bus bar on the negative end of the battery holder. That took a while to heat up before it'd take solder. But, once you get there, the solder flows for longer too.

author: UF8FF
author_rank: Contributor
timestamp: January 23, 2017, 06:18:26 am
content: Success! One down, one to go. All of your tips helps tremendously. In the end I actually went component side on one leg and added flux and heated it as you said and it worked like a charm.

author: bitseeker
author_rank: Super Contributor
timestamp: January 23, 2017, 06:49:35 am
content: Great news. Keep up the good work!

author: t1d
author_rank: Super Contributor
timestamp: January 23, 2017, 08:16:06 am
content: Go to YouTube and search for "desoldering" techniques... There are l-o-t-s of different methods... I learned a bunch, there...For multi-pin ICs, I might use the hot air method... Reflows all the pins at once and you just lift the IC off the board... I have a desoldering pump, but it is not always the best method to use, even though it is a wonderful tool...I DIY'd my pump... Works, but I sure envy your Hakko... Great price!

author: mcinque
author_rank: Unknown
timestamp: January 24, 2017, 11:27:46 am
content: Quote from: UF8FF on January 23, 2017, 06:18:26 amnice to hear it!

author: KL27x
author_rank: Super Contributor
timestamp: January 24, 2017, 08:59:12 pm
content: I'm late the the party. But looking at your pic, the problematic pin looks like a ground pin. You can see it is connected to a large plane on the bottom. Perhaps on the top and/or internal planes, too.When you have one pin of a device/header that causes a problem, like this, it's usually due to heatsinking. Leave the tip pressed for an extra 2-3 seconds before hitting the suction. And if that doesn't work, put a little more solder on the bead if necessary, turn up the heat, and try again.Also, might be helpful to get a good spring loaded solder sucker for the really stubborn pins. That way you don't have to burn up your expensive desoldering gun nozzle/tip. And a good solder sucker has a lot more peak suction than a desoldering gun with motorized vacuum.

author: james_s
author_rank: Super Contributor
timestamp: January 25, 2017, 05:51:51 am
content: I never had any luck at all with those spring loaded solder suckers. In most cases I found it impossible to keep the heat on the joint at the same time as sucking the solder out. The Hakko 808 is a wonderful tool as long as it's maintained. I'm still using the tip that came on mine when I bought it, I have two different sizes for different tasks.

author: bitseeker
author_rank: Super Contributor
timestamp: January 26, 2017, 03:03:18 am
content: I find the spring-loaded solder suckers to work well on old power supplies that have components soldered to turrets. The amount of solder tends to be a bit much for the THT vacuum desoldering iron.