Can someone recommend a preheater for large boards (up to ATX size)

[dicky96]

Hi guys
I have a semi-auto BGA rework station already but I've been playing around with cheaper options on my YT channel

I'm currently looking for a preheater suitably large enough for ATX motherboards to use with my Quick 861DW

I had a look on aliexpress and this one keeps coming up
https://www.aliexpress.com/item/1005...archweb201603_

Says it is 1600W and seems to be about big enough but I couldn't find any reviews to see if they are actually a usable piece of kit or not. Does anyone have one of these, something similar, or other suggestions

Thanks

[megaraider]

I'm not the best adviser on this subject...
That being established, the major short come will be the actual preheated plat size 260x240.
ATX motherboards usually take up to 300 cm or more in length. Although not all the the motherboard area needs preheating, the motherboard itself takes it space to seat.
It's also over rated in power, nothing new, at full power draws 1200W.
See consumer reviews here.

[dicky96]

Thanks megaraider - well it seems it has 5 out of 5 star rating so it may not be junk

I accept an ATX motherboard is a bit larger than 260x240 but that does seem to a reasonably big heater size

I was trying to put together some YT videos which determine how to do difficult things such as change a LGA socket using the minimum possible cost of equipment so that this sort of repair is accessible to more hobbyist repairers

Yeah I can put it on my €3500 BGA station but that isn't the point of what I was trying to do, I wanted to prove if it is possible with for example a Quick 861DW, or similar, and a preheater - say 200-300 euros worth in total, as that is much more in the range of availabliity for a lot of people who may have the skills but not the finance.

In the two attempts I made so far
This one I published https://www.youtube.com/watch?v=x9Xiv19Kx-8 if you watch you will see it was not successful

And the other video I didn't upload yet (Asrock H97M), it appears to confirm that the problem does not seem to be getting enough heat into the job, it appears to be more to do with the distribution of heat. The one I didn't upload, I again managed to remove the LGA without ripping any 'connected' pads, but the upper surface of the PCB was uneven again, and I managed to burn tracks off the bottom of the PCB trying to resolder a new LGA even using two thermocouples to monitor things

I honestly don't know if what I am trying to achieve is actually do-able, though I suspect it probably is, but for sure it makes for some interesting experiments

[megaraider]

Originally Posted by dicky96

(...)

It's still a nice result with the tools you used...! Nice effort!
I think it's doable..., but a question pops-up:
Socket desoldered with success THEN what...? Because soldering a new one will be impossible!

[Obvious correction on my previous post: "300mm" not "300cm"]

[clearchris]

Most of this equipment is probably buildable with a 3d printer, a few parts and an arduino. Not commercial grade, but good for hobbyist work. I'm actually pretty surprised I haven't seen more builds out there.

Some light reseaching at hackaday yields an even cheaper and possibly quite effective solution. Do these boards you are working on have smooth undersides, or are there SMT devices under there? If it works, it's hard to beat $10.
https://hackaday.io/project/11566-ha...-smd-soldering

Kind of bothers me that the temperature isn't controllable, but 230C is pretty close to where you need to be. Might be too hot though.

[dicky96]

@megaraider
Why would soldering a new one be impossible? It's just the reverse of removing one isn't it, with the advantage of getting fresh flux under it? And the replacement sockets are cheap

Having said that I find it harder to fit replacement LGA sockets successfully on my BGA machine than I do removing them for some reason - I would have thought the same profile that removed the old one would solder the new one but I generally find not all the solder balls melt for some reason

@clearchris
That depends on the boards - some are smooth underneath and some have a handful of capacitors there - I'll check out the link, thanks

[clearchris]

Originally Posted by dicky96

That depends on the boards - some are smooth underneath and some have a handful of capacitors there - I'll check out the link, thanks

Yeah, I remember seeing that on some boards, but I haven't seen anything relatively modern, all my boards are probably 10+ years old. Everything else is a laptop, and those are definitely packed, both sides.

I have seen people use a salt or sand bed with a board heater. Not sure how well that works, but I may try it before going with an infrared system.

[megaraider]

Originally Posted by dicky96

@megaraider
Why would soldering a new one be impossible? It's just the reverse of removing one isn't it, with the advantage of getting fresh flux under it? And the replacement sockets are cheap

My comment never meant to depreciate, no way.
Just wondered if one can use the hot air flow gun to solder the new socket since the plastic / compound material on the socket will melt...

[dicky96]

Yeah I see what you mean. Obviously the socket has a maximum temperature it can withstand. On my BGA machine it has IR peheater plus upper and lower hot air - so really it is just like using a hot air gun to solder the replacememt socket

Obviously that has profiles to ensure the new socket doesn't melt. But if you program a profile wrong then you *will* melt the socket and/or burn the board. I've done it once myself using that machine to replace an LGA. And I've trashed a few BGA chips too

My current thinking is, if you can get the board warm enough using a preheater below it, and in a fairly even fashion - then the fact your hot air station is not heating the socket evenly while resoldering is less relevant as you don't need to apply much more heat to 'push it over the edge' and liquify the solder balls. But this is all conjecture of course at the moment

[Noo0b]

Sorry for resuscitating this thread.
I followed Learn Electronics Repair's youtube videos here and now I'm quite not encouraged to try repairing an LGA 1700 socket. I looked at the Kada 853b on Ali and really felt compelled to acquire it even if it is just for playing around with old boards.
As for the actual socket repair:
I have "no" Equipment per se but an old Madell 850b that I just brought back with epoxy and an ambiguous voltage resistance that may be somewhat iffy - with the resistance temps 450~500 c but nozzle below 180 c on the IR gun. (Not sure if that's correct, maybe it's ok - tech friend says its hot, red and fast).
I have "no" skills. All relevant experience I had was reflow a lot of XBox 360's back in the day. I still have some of the boards that did not repair though.
I have "no" funds. Whatsoever.
What I have is a cheap IR gun that might not be very precise, the rework station, a rework station handle stand, a solder iron with tips, a solder sucker, a large rubber mat, some flux and wick.
Should I invest in buying the Kada 853b or maybe something not to far from it's price and try it on the x360s before going for the expensive socket stuff or save the money for someone to try it?
I really don't care about spending on it but if it's useless and I'm just going to damage stuff and waste time relying on the IR gun and unknown solder temps I will not do it and let the boards collect more dust/find a decent affordable repair for the socket.
Thanks for the posts and for reading!
Kind regards.

[diif]

No, save your money. Don't buy the Kada 853b.
Buy some scrap boards, practice removing and replacing components with both hot air and your iron.
A cheap thermometer with a probe can be bought for under $10/£10, it enables you to have an extra hand to work with and you can concentrate on the job and watch the temperature move.

[Noo0b]

Thanks for the reply diif.
The Kada 853b does not seem to be most appropriate for the repairs I want to do - LGA 1700 and AM3 sockets. Looking at the LY IR6500 v2 on AliExpress tempted me buying it for myself, but not knowing if it's the right size, customs uncertainty and all the reviews about the profiles, and the thermocouple and lamp issues it was too much of a risk to take for someone with no experience.
I have about a dozen X360 boards that I wasn't able to reflow that I could use for experience. With the 850b working, I just need to get a stencil and solder balls.
Once I get everything set I'll record and post what I tried.
Thanks again for the reply, kind regards.

[diif]

The 850b is hot air, you still need to heat the whole board, especially if you want to reballl processors.

[dellxps15]

yesterday i have ordered this: https://it.aliexpress.com/item/10050...yAdapt=glo2ita

will use it for preheating large board for small smd remove , as my hot air is not able to remove them alone.
got the 95€ version with hot air holder.

[diif]

Originally Posted by dellxps15

yesterday i have ordered this: https://it.aliexpress.com/item/10050...yAdapt=glo2ita

will use it for preheating large board for small smd remove , as my hot air is not able to remove them alone.
got the 95€ version with hot air holder.

It's only got a 12cm heating area, that's designed for phones not large boards.

[dellxps15]

yes i just need to heat a bit large board for remove small component, like ram bga and so.
ofcourse ill use hot air on top.

for large bga i have 2.7kw IR bga rework station

[dellxps15]

i got the preheater aftwe around 25 days and it works perfectly. it much much better remove component from imacs board