juno 106 chip desoldering

[elsquirrel]

I'm trying to desolder a failing 80017a voice chip from my 106 so I can attempt the acetone method to try to save it.
I've removed most of the solder with braid but there's always a small amount still left in the actual hole where the legs sit and I cant wiggle the chip loose. If I can't properly desolder it I guess I'll just snap it off and install a clone chip, but I would like to try this method first.

Any tips for getting it out? I've also tried adding more solder and trying to grab it out (as per a tip I found on the internet) but always seems to cool before I can get it out. It sounds like witchcraft, or maybe I'm doing something wrong.

[madtheory]

Solder sucker.

[elsquirrel]

Ive tried that too. I'll have another go. Not super confident the sucker I have is powerful as possible though. I think it was only $1.50.

[madtheory]

Mine was €10 about ten years ago. I never use braid. I've done two Juno voice chips with it.

[elsquirrel]

Do you heat the solder and try to draw it up at the same time with the sucker on an angle or do you heat the solder and quickly apply the sucker so it makes full contact to the board? (i.e directly up)

[Stab Frenzy]

For the solder sucker to work properly you need to add a bit of flux or solder with flux core when you're reheating it to get it to flow properly.

[synthparts]

It is real easy to lift solder pads and board traces on those Roland thru-hole soldered boards. You want to heat those pads just a very short period of time. The best thing to use is a vacuum pump desoldering station. I highly recommend the Hakko 808.

[synthRodriguez]

+1 on the Hakko 808. Pricey though for the occasional repair.

I got mine when I decided that:
a) I seemed to be tearing into enough vintage synths and arcade games to justify it, and
b) I'd had enough of SolderWick working about 60% of the time.

With the Hakko you can easily remove 12-14 pin chips. I've had them literally fall out. Occasionally you have to resolder a pin and suck it out again, but 95% of the time it goes without a hitch. I've never had to clip out a belligerent IC like I used to do with SolderWick.

The wide solder braid is good for absorbing big blobs like power lead connections though so I still keep it around.

[rhino]

Vacuum desoldering station is the only way to go. First time you need to replace a 40-pin chip, you'll know why.

[HideawayStudio]

The difficult pads to clear are almost always connected to the power plane due to the heat being sinked away from the joint by the surrounding copper.

Sometimes this helps removing stubborn PTH components but be careful not to lift the pads...

Remove as much of the old solder as you can with solder braid and then flood the joint with fresh new solder. Whilst the joint is still hot then quicky remove it with the solder sucker.

By far the quickest way to replace those modules (I've done a few myself) is a method that is probably not going to be any use to you as you are wanting to save the module:

You will find most service engineers simply don't bother trying to remove a PTH component whole. The usual trick is to use a very fine pair of side cutters and snip off all of the legs on the IC or module. It's then a relatively trivial matter of removing each of the remaining pins one by one with an iron and some tweezers. I've changed a voice module on a 106 using this method in literally 5 minutes and countless DIP chips on synths.

There are some professional tools to help remove ICs/SIL modules in tact but most are very expensive:

The cheapest option is to invest in a heated solder sucker. There are some relatively inexpensive self contained units on the market but be very careful not to damage the plate-thru's with them and lift pads. Better still is a self contained vacuum powered heated solder sucker as suggested above.

On the soldering iron front Metcal do some superb RF powered irons which are capable of putting tremendous amounts of heat into large areas of copper without cooling like lesser irons suffer from. You can get really wide (1" wide!) chisel desoldering bits for these irons that allow you to apply heat to several pads on a SIL component in one go whilst pulling.

There is another secret weapon but I don't know much about it. There is a very special solder you can get which is a bizarre alloy that when mixed with solder lowers its melting point to a silly temp. This permits many legs or pads to be heated in record time which allows the device to simply slide or fall out of the pcb.

[rhino]

There is another secret weapon but I don't know much about it. There is a very special solder you can get which is a bizarre alloy that when mixed with solder lowers its melting point to a silly temp. This permits many legs or pads to be heated in record time which allows the device to simply slide or fall out of the pcb.

It's called "Chip-Quick". Works wonders on flatpacks and SSOP chips, but not much help on DIPs.

[garranimal]

Another +1 for the Hakko 808. Worth every red cent, the most reliable way to remove juno voice chips.

The only other thing I could suggest is a PCB board holder like the PanaVise. The idea being to position the pcb vertically so that using the braid method gravity will help pull down the solder.

[elsquirrel]

Thanks for the info. I'm not really a big repair guy, just changing batteries and obvious stuff here and there.
De-soldering station looks cool, just don't think I'd get much use out of it to justify the cost. Probably end up having to pay someone else. Goddamn you juno 106.

[madtech]

Maybe it will help if you actually watch a person accomplish the task. It is critically important to reflow the joints before starting and you have to leave the iron on the joint longer than you think. I have removed two sets with the solder braid but the desoldering station like the Pace or Hakko's are the best option. But patience will pay off and you can remove them. Remember what he says about having a little too much heat versus too little!Don't wiggle too much of those chips or the legs will detach. Good luck!

[elsquirrel]

I don't plan to damage anything if I can help, but out of curiosity how serious is damaging a trace? Are they repaired easily enough, or would that be a huge nightmare?

I think I've seen a video of someone scraping a trace and re-soldering it or something but given I can't even get a chip out I'm assuming it's beyond my skill-set.

Just tossing up whether to give it one more try or snap the chip/pass it to more capable hands.