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Fine soldering help needed: broken laptop keyboard ZIF connector
jasonbar:
Can somebody here perform a fine soldering task or point me to someone who can?
Long story short:
HP 15T-N200 laptop. Keyboard ZIF connector snapped pretty cleanly off of PCB. Connector is in a few pieces. Connector is (was) a 32-position, 1 mm pitch, horizontal, surface mount, ZIF connector, & an equivalent replacemetn parts is as unattainable as a unicorn.
This Dropbox folder shows hi-res photos of the relevant parts, & I attached some lo-res pics to this post as well: https://www.dropbox.com/sh/57r1n2o4c2r8gbl/AAAIVa1htRQ-Gi6D4VZnD9j8a
So far, local PC repair shops, even ones that advertise motherboard repair, are not enthusiastic about fixing it. I'm confident that this could be repaired reasonably by using an alternate floating connector replacement or even hard-soldering the keyboard flex cable to the motherboard if necessary. It "just" needs somebody who is accustomed to some fine solder work.
Thank you very much,
-Jason
PS--after 1,870 posts over 7.5 years, I finally just noticed the "Message icon" drop-down menu. Wow.
RandyT:
Ouch...I was hoping this was a cheap unit so I could easily tell you to "junk it", but I see that it is not. Is this something you bought cheap, hoping to fix it, or a personal mishap?
The issue at hand is that even if you could find a connector, it appears to be one which you couldn't even solder to (i.e. requires reflow). I'd also be very surprised if it was possible to solder directly to the cable without destroying it. If it were upside down (and actually had some metal contacts exposed) it could be trimmed back to the contacts, held in place with some hot melt, and each solder point carefully bridged. But it's not, and I doubt this type of cable would hold up to the heat. It may not even have any real metal in it to actually solder to.
The prognosis is not good, I'm afraid. Likely a $200 job for anyone who values their time, if it's even possible. Probably best to put this in a bartop or cabinet, or use as a desktop system with a USB keyboard.
jasonbar:
Thanks for the input, Randy. I appreciate it.
I got out my multimeter to check for continuity between the motherboard's rectangular ZIF pads & the neighboring round pads just to their left, in the cases where I could see a clear trace connecting them. I tested a handful & got continuity on only a couple.
Dragging the multimeter probe over the PCB surface, it does feel as if each rectangular pad is a depression, as if the trace did indeed come out.
I added pictures 9-14 to the Dropbox folder: https://www.dropbox.com/sh/57r1n2o4c2r8gbl/AAAIVa1htRQ-Gi6D4VZnD9j8a
These show the bottom of the ZIF connector, & the side-lit shots of the PCB seem to show shadows indicating that the rectangular pads are sub-flush.
I don't necessarily need an exact "stock" replacement. My research has shown that a 1mm pitch, 32-pin, surface mount, horizontal, ZIF connector is as rare as a unicorn.
So, I'm not averse to a skilled workaround where we could solder to the available neighboring pads a fresh connector on flying leads (ribbon cable?) & then plug the keyboard ribbon cable into that connector. It's a modern laptop, so it's slim, but there is a little volume available here, especially if we trim away the steel frame/EMI shield a little, & the keyboard flex cable gives some flexibility.
Or, there are connectors readily available just like the broken one, but in a maximum of 30 positions, so perhaps the cable could be carefully slit lengthwise to feed into a 30-pin connector & a neighboring 2-pin connector, or some other such split (pin 14 on the keyboard ribbon cable appears to be unused & may be a reasonable location to attempt a split).
I'm also not averse to a more "permanent" solution of hard-soldering between the PCB & ribbon cable, eliminating the removable functionality of the keyboard. If there's good strain relief, in the rare case that I'd need to get in to change the hard drive or other component under the keyboard, it can be done. Of course, a coffee spill that breaks the keyboard is another story...
Gotta find a guy who does lots of RGB mods on consoles--they're not afraid to run super fine wire from super fine pads... :]
Thanks,
-Jason
MonMotha:
1mm pitch? Trivial to solder. The 0.5mm ones get a bit tricky but aren't too bad once you get the hang of it.
Unfortunately, you've torn the pads off the PCB. That'll make it a lot harder to repair. Still not impossible.
As has been pointed out, the issue is finding the connector. 32 positions is not common. I can't find any distributors stocking them for qty. 1 purchase. I can ask my guys at Arrow if they know of anything.
For reference, this is commonly called an "FFC Connector", FCC meaning "Flat Flex Cable". The style appears to be a rotary backlock.
jasonbar:
Thank you for your input. Yes, the issue seems to be that this clamp flipped up from the "back" side, opposite of where the flex is inserted, rather than the "front" side, like most of them (AFAIK).
Even a connector w/ > 32 positions might be a candidate to be cut down...?
Thanks,
-Jason