Replace a 154 pin ECU connector

[4cx10000]

Hi!

I am about to replace, not ordered yet though, a 154 pin ECU connector. 154 pins is quite a number to unsolder, but I am prepared to do it even though I have not done it before. Anyone done it and if so, what would be the first words that come into your mind and also, if there is anything special I will have to consider?

Thanks in advance! 

[Ian.M]

If you've got a 1% chance of FUBARing the board per pin you need to desolder, you've only got a 21% chance of success!  If you break the plating to board bond of a thru-hole connected to an inner layer track in a multi-layer board, you'll only be able to fix it with a bodge wire if you know where the track goes, so map out all the pins in advance before attempting to desolder the connector.

Is it feasible to cut all the pins at the back of the connector shell, so they can be bent up, desoldered one at a time, and pulled out from the top side, to minimize the risk to the board?

[4cx10000]

Thanks for reply Ian.M!

Oh yes! I am aware of the plated thru-holes and that is what threaten me!  Yes, that was also my plan, but do you think it will will end up, by cutting all the pins and just apply enough heat to drag them out, in a nearly 100 % success? There are of course ground planes and guess they are, as always, a little tricky. Thanks for the warning and I will absolutely try to map out all the pins ... all 154! 

[Ian.M]

'Just enough heat' is very risky as you cook the board for longer getting it up to temperature, and there is always a risk that the solder in the depths of the hole hasn't fully melted.   Instead, you should be using the largest practical hoof bit for good heat transfer, with the temperature set to the upper end of the usual rework temperature range, limiting time per joint and *NOT* doing adjacent pins consecutively (i.e. do every fifth pin, cycling back to the start till all are done)  to limit localized board heating.  When you get it down to a pin at each corner, stabilize the connector body position with bluetak so you don't torque the last pin in its hole!

Maybe get some ChipQuik low temperature alloy: https://www.chipquik.com/store/index.php?cPath=200
to lower the melting point enough to reduce the risk of board damage when pulling the pins.  Go round the connector once with flux and a solder sucker, without attempting to move any pins, to reduce the amount of solder in each joint, then add the ChipQuik alloy to each joint before attempting to pull that pin.  Clean up the holes with desolder braid and plenty of flux after the connector is fully removed. 

[PKTKS]

Still to order MECHANIC low temp alloy...

https://www.aliexpress.com/item/33025714253.html

if that would help high thermal mass PCBs

still to see

Paul

[tooki]

Hi!

I am about to replace, not ordered yet though, a 154 pin ECU connector. 154 pins is quite a number to unsolder, but I am prepared to do it even though I have not done it before. Anyone done it and if so, what would be the first words that come into your mind and also, if there is anything special I will have to consider?

Thanks in advance! 

This is not the item you want to be learning how to desolder with!!! You need to practice with demanding trash boards (like old PC motherboards), not your patient!

And what desoldering method were you planning to use?

[jmelson]

You need a Pace-type desolderng system, with a vacuum pump that sucks the solder out through a hollow soldering iron tip.  You place the tip over the pin on the PC board, wait a few seconds for the solder to melt all the way through to the back side of the board, and then "swirl" the tip in a circular motion while activating the vacuum pump.  When you get all these steps right, the connector simply FALLS off the board when it is picked up off the bench.  But, it takes some experience to know what temp to set the iron to, how long to wait for heating of the pin, etc.

Don't even ATTEMPT this with desoldering braid, those piston-type solder suckers, etc.  Those are fine for components with a couple leads, but not this.

Jon

[bdunham7]

Definitely a job for a good vacuum desoldering tool, my Hakko FR301 all cleaned and ready with just the right tip would be the absolute minimum I would want to try this with.  The extended snout types might be the safest.  Definitely cut the connector off and leave just the bare pins if at all possible, even if this takes several hours of work.  You want each pin to come out easily after you suck the solder out, ideally they just fall out.  Tugging hard with the solder not fully melted and sucked away will be the most likely way you will damage this.  Excessive heat is the other.  If you are new to desoldering, definitely practice on something else.

[aqibi2000]

Would recommend using a large nozzle hot air station to remove this after preheating the under side of the board to 150 and maintain that temperature for 2-3 minutes

Or an IR Rework Station, can help I’ve got a Jovy RE8500

[4cx10000]

Hi!

I am about to replace, not ordered yet though, a 154 pin ECU connector. 154 pins is quite a number to unsolder, but I am prepared to do it even though I have not done it before. Anyone done it and if so, what would be the first words that come into your mind and also, if there is anything special I will have to consider?

Thanks in advance! 

This is not the item you want to be learning how to desolder with!!! You need to practice with demanding trash boards (like old PC motherboards), not your patient!

And what desoldering method were you planning to use?

Hi tooki!

I can assure you that I need no, whatsoever, training on an old PC motherboard being in electronics repair business for nearly 35 years; but it would be foolish of me to not take the opportunity to ask in this forum if anyone, of all the highly skilled people that it keeps, have done it with success and how they did. My intention was, before I posted here, to use my Weller WXD 2 which also has vacuum desoldering option. Absolutely no desoldering braid which jmelson pointed out. So ... I did not want to plow in here stating that I have nearly 35 years of experience, because that would probably hold back suggestions that I might not have thought about. An old dog like me like to keep learning - that's why.

[4cx10000]

'Just enough heat' is very risky as you cook the board for longer getting it up to temperature, and there is always a risk that the solder in the depths of the hole hasn't fully melted.   Instead, you should be using the largest practical hoof bit for good heat transfer, with the temperature set to the upper end of the usual rework temperature range, limiting time per joint and *NOT* doing adjacent pins consecutively (i.e. do every fifth pin, cycling back to the start till all are done)  to limit localized board heating.  When you get it down to a pin at each corner, stabilize the connector body position with bluetak so you don't torque the last pin in its hole!

Maybe get some ChipQuik low temperature alloy: https://www.chipquik.com/store/index.php?cPath=200
to lower the melting point enough to reduce the risk of board damage when pulling the pins.  Go round the connector once with flux and a solder sucker, without attempting to move any pins, to reduce the amount of solder in each joint, then add the ChipQuik alloy to each joint before attempting to pull that pin.  Clean up the holes with desolder braid and plenty of flux after the connector is fully removed.

Hi Ian.M and thank you so much for taking your time!

That was a good point, as well as all the other advices you shared, using ChipQuik low temperature alloy! I recall that I have a spool somewhere, but at the time of writing not a clue where!  I will, as soon as the connector is on my workbench, take som photos and put them here. I have done quite a few similar connectors before, but, as I thik I stated in one of my posts, not one of these and absolutely NOT a 154 pin bastard.  I am so glad for all advices I get; thank you so much! 

[perieanuo]

hi,
well you have another -tested by me when I was doing r&d in electronics pcb manufacturing- method: the solder 'bath'
my boss had some 3kw cooking induction plate (yep, just some cheap one) and he did made something like a solder bath filled with solder, I really don't remember if it was pb-free or not...
we just heated the solder (the rectangular solder recipient was full at maximum with solder) until the solder was really liquid then just put the pcb with the connector needed to be desoldered upside of course and with a good plyer after 2-3 seconds max you get the connector free, you lift the pcb (otherwise you can damage the board) and you can easyili separate pcb and connector
we took off hundreds of connectors from deprecated designs
the only secret is the 'hand' that operates this, just test with some bad pcb's
ok, it will cost you the solder inside the bath (you have this brick of solder trapped in his recipient only for desoldering purposes like this one, and it's lot of solder)
the method is an old-time-one from 80's when we haven't got hot-air top notch soldering stations in small companies or in est-european countries, where ingenuity was necessary to overcome missing quality tools like in west-eu countries
because the heated mass is relly big, it works 100% even with veeeery big stuff like your connector

damage to pcb/tracks/vias is zero if you keep it quick (touching the pcb with the liquid solder, wait 2-3 seconds with the pcb on the solder without submerse the pcb in the liquid, only touching it, testing with the plier if the connector is lifting up from the board and then lift the board and taking out the connector)

the recipient was something like this one http://superbproduct.com/Solder-Bath-SBPTC-500.html (only the bath I mean, not the heating part)

don't be afraid, if you got this right, you're the boss
best regards, ovidiu

[JPortici]

what i would do since you don't have to keep the old part: exactly what you tought you would do in the first place.
Cut ALL the pins so the connector comes away, desolder all the pins one by one.
Bonus, you can desolder some now, some later

[tooki]

Hi!

I am about to replace, not ordered yet though, a 154 pin ECU connector. 154 pins is quite a number to unsolder, but I am prepared to do it even though I have not done it before. Anyone done it and if so, what would be the first words that come into your mind and also, if there is anything special I will have to consider?

Thanks in advance! 

This is not the item you want to be learning how to desolder with!!! You need to practice with demanding trash boards (like old PC motherboards), not your patient!

And what desoldering method were you planning to use?

Hi tooki!

I can assure you that I need no, whatsoever, training on an old PC motherboard being in electronics repair business for nearly 35 years; but it would be foolish of me to not take the opportunity to ask in this forum if anyone, of all the highly skilled people that it keeps, have done it with success and how they did. My intention was, before I posted here, to use my Weller WXD 2 which also has vacuum desoldering option. Absolutely no desoldering braid which jmelson pointed out. So ... I did not want to plow in here stating that I have nearly 35 years of experience, because that would probably hold back suggestions that I might not have thought about. An old dog like me like to keep learning - that's why.

Fair enough! The wording of the original post made it sound like you’d never desoldered before.

Out of morbid curiosity, what failed that’s necessitated replacing the connector?

[4cx10000]

what i would do since you don't have to keep the old part: exactly what you tought you would do in the first place.
Cut ALL the pins so the connector comes away, desolder all the pins one by one.
Bonus, you can desolder some now, some later

Thanks JPortici!

Guess you are thinking of those who are connected to groundplane and without doubt will be the nastiest. Hopefully these will be solved by the advice from Ian.M. IE; "you should be using the largest practical hoof bit for good heat transfer, with the temperature set to the upper end of the usual rework temperature range". As I wrote in another post; I will post some photos when I have the connector on my workbench.  Never done a 154 pin connector before, so the key is: "stay focused for every each of the pins".   

[Ian.M]

You need a Pace-type desolderng system, with a vacuum pump that sucks the solder out through a hollow soldering iron tip.  You place the tip over the pin on the PC board, wait a few seconds for the solder to melt all the way through to the back side of the board, and then "swirl" the tip in a circular motion while activating the vacuum pump.  When you get all these steps right, the connector simply FALLS off the board when it is picked up off the bench.  But, it takes some experience to know what temp to set the iron to, how long to wait for heating of the pin, etc.

If you have a desoldering station or tool with a high thermal mass tip that can be kept properly tinned, it *may* be viable to follow Jmelson's advice.  Preheating from the component side with delicate areas  of the rest of the  board masked off with Aluminum foil and Kapton tape will improve the odds.   However if the pin to hole clearances are tight, maybe even to the point the pin corners are press-fit in their holes, it wont go anywhere near as well as the best case Jon describes, and you'll have to resort to destroying the connector body to permit individual pin removal while keeping that joint molten as discussed earlier.

Don't even ATTEMPT this with desoldering braid, those piston-type solder suckers, etc.  Those are fine for components with a couple leads, but not this.

Jon

If pin to hole clearances are generous, hot air preheat to the maximum the connector or other delicate parts will fully withstand, and a *GOOD* solder sucker with silicone tubing over its tip to conform to the board is used in conjunction with a high power hoof bit iron, its quite possible to remove such a connector intact without wrecking the board despite Jon's advice to the contrary.  You need to 'spring' each pin to check it isn't adhering to the hole plating, reheating any that are stuck and holding them away from the hole wall while they cool.    However ChipQuik makes it much less risky as its then possible to keep the solder joints molten with preheat without cooking the board or sensitive components on it.  Without ChipQuik, desolder braid is *useless* for pins with inaccessible power planes and no thermal relief, or tight hole clearances.

[4cx10000]

Fair enough! The wording of the original post made it sound like you’d never desoldered before.

Out of morbid curiosity, what failed that’s necessitated replacing the connector?
[/quote]

Hi tooki! 

These ECU connectors are prone to moisture and water ingress just because of its bad location in the vehicle it belongs to. What happens is that one or several of the pins are, more or less, totally destroyed and usually the pin('s) in one of the connector corners. Its entrance comes, most probably, through the cable harness.

In order to get things done I solved couple of them with bypass wiring from inside the ECU. Absolutely NOT the best solution, but with permission from the customers. In this case there are 5 pins gone and several others are green with a slight waist next to the bottom of the connector. 

[perieanuo]

what i would do since you don't have to keep the old part: exactly what you tought you would do in the first place.
Cut ALL the pins so the connector comes away, desolder all the pins one by one.
Bonus, you can desolder some now, some later

why not, old dremel/proxxon method for extract works too
my long story is necessary when you need the extracted connector intact

[fenugrec]

with permission from the customers.

Key word  : "from the customer" - how hard have you looked for a scrapyard pull / used ECU ? Perhaps even from a different but similar model, then reflashing the correct firmware. What make/model does this go on ?

If you're committed to replacing the connector, invest in a desoldering tool (I skimmed the thread but didn't see if you already have one). They are expensive but since you're presumably getting paid for this and possibly other small jobs, it will pay for itself quickly. I got one of the pistol-type Hakko FR-something a while ago; I feel dumb for having waited so long to invest in one.
In other words : there's no way you're going to regret buying a quality tool that does something better and faster than any other method.

[ifrythings]

I removed pretty much that exact connector from a car computer, all I used was a HAKKO FR301 desoldering gun, I believe it also removed the 6 high current pins in the center of the connector to.

Be careful if you start using hot air rework stations on this, under the connector is a ton of decoupling caps.

[4cx10000]

I removed pretty much that exact connector from a car computer, all I used was a HAKKO FR301 desoldering gun, I believe it also removed the 6 high current pins in the center of the connector to.

Be careful if you start using hot air rework stations on this, under the connector is a ton of decoupling caps.

Thanks ifrythings!

Well done and yes, it seems to be exactly the same as in the ECM I got!  Yupp, there are a bunch of decoupling capacitors right next to the pins. I have a Weller WXD2 which also has a de-soldering gun, actually the very best soldering/de-soldering station I have ever had. BTW, I ordered the connector from a seller in USA and if everything goes well it will arrive first week in 2021. Really looking forward to get the job done, but 154 pins! 

[tooki]

It might be worth getting some low-melting-point solder (ChipQuik and the like) to dilute the original solder with, to make it easier to extract.

[james_s]

I would not hesitate to do this with my Hakko 808, it's going to be tedious to desolder 154 pins any way you look at it but the tool would make quick work of each of them.

[geggi1]

I assume that the old connector is going to be discarded.
Looking at the picture of the connector I would cut the pins a few mm over the top of the PCB.
Remove the plastic parts and do one pin a time this will require less heat and also simplify the removal of old solder.

[rvalente]

Cant you replace the ecu and copy the data from the older one?