David1
Posts: 14
Joined: Mon Sep 30, 2013 2:43 pm

Replacing keyboard connector on motherboard

Tue Jun 15, 2021 2:02 pm

When opening my RPi 400 to take a peek inside, I mistakenly thought the keyboard ribbon cable connector was a 'slide to open' rather than a 'flip to open' connector with the result that I now have a broken connector! Grrr! My repair attempts at gluing the tiny broken fragment have been unsuccessful. The 400 works fine with a USB keyboard plugged in but... I'm still spitting nails over my carelessness.

I have done SMD work before and I think I could manage replacing the connector - if I could source a replacement. However, I have been unable to locate a supplier for this inexpensive, tiny, but critical, part.

Does anyone know where I could get an exact 26-place socket replacement? (I'm in Canada so a North American source would be preferable - but I'll order from the UK, China, etc, if needed.)

David

aBUGSworstnightmare
Posts: 3230
Joined: Tue Jun 30, 2015 1:35 pm

Re: Replacing keyboard connector on motherboard

Tue Jun 15, 2021 7:16 pm

Only seen it on some pictures, bit I think it's 0.5mm pictch (measure/compare to known the cable pitch), so you can have a look at digikey/mouser

David1
Posts: 14
Joined: Mon Sep 30, 2013 2:43 pm

Re: Replacing keyboard connector on motherboard

Tue Jun 15, 2021 8:13 pm

Thanks for replying. I measured and counted - the cable is a 1.0 mm pitch, 26 conductor FFC ('flat flexible cable' - I think that's the term).

The main problem is that there are *many* connectors at Digikey (and likely Mouser, too) that appear to fit the cable 'end' but I'm concerned about fitting it onto the PCB pads.

SMD work is hard enough for me - I don't want to try to fit a part that is physically different from the one I"m replacing. I'll likely get a single shot at the repair before I risk damaging the PCB.

I was hoping that someone might actually know an exact replacement part (manufacturer/part number) for the connector on the PCB.

David

electronicstoday
Posts: 41
Joined: Fri Nov 15, 2019 4:02 am

Re: Replacing keyboard connector on motherboard

Tue Jun 15, 2021 11:59 pm

If it were me, I'd watch a wide variety of "teardown" videos before doing this; not because you're not capable or competent enough, but because it saves this kind of damage. That said, experience teaches one which connector type is which at a cursory glance, but then there's ALWAYS that one occasion where you are "100% certain it's this type" and isn't. I hope you repair it my friend. :geek:

David1
Posts: 14
Joined: Mon Sep 30, 2013 2:43 pm

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 2:58 am

Yes. Experience is a great teacher. As are videos. I had started watching a video but it was so long and dull (and I didn’t like the way he just pulled off the heat sink without warming it a bit to loosen the adhesive) that I just barged ahead. Later I watched more of it and he clearly showed “flipping” the latch vs sliding it! For whatever reason, none of the previous connectors I have used were the flip open type. Live and learn.

I hope someone knows the part number!

David

aBUGSworstnightmare
Posts: 3230
Joined: Tue Jun 30, 2015 1:35 pm

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 4:50 am

There is no public scgematic/BOM for the Pi400, so no 'nirmal' forum member will know the part no.

You can use filters on digikey/mouser now to narroe down your search. Inspect rhe connector if there are some manufacturer logos and then look at the connector candidate specs to see if they will fit the footprint. You will only open/close it once after the repair, so even if you can solder the pins only it will be fine.

electronicstoday
Posts: 41
Joined: Fri Nov 15, 2019 4:02 am

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 8:10 am

David1 wrote:
Wed Jun 16, 2021 2:58 am
Yes. Experience is a great teacher. As are videos. I had started watching a video but it was so long and dull (and I didn’t like the way he just pulled off the heat sink without warming it a bit to loosen the adhesive) that I just barged ahead. Later I watched more of it and he clearly showed “flipping” the latch vs sliding it! For whatever reason, none of the previous connectors I have used were the flip open type. Live and learn.

I hope someone knows the part number!

David
I’d grab a powerful magnifier and look for any printed on/moulded in numbers/assembly numbers etc. Never underestimate the power of Google to be able to find treasure from VERY short numbers - an example of this is SMD transistors which often have only 3 characters on them, and yet they’re easily found.

Alternatively, you could find one which mates the ribbon end, even if the footprint isn’t right, then glue it to the board and run wire links between them. If you want, take some high res photos, very clear ones of ALL SIDES AND MARKINGS and share here and I’ll do some Google fu for you (I’m extremely dogged and don’t give up, and I mean that - I rarely don’t find anything, often will search on and off for. many months.)

You could do worse than to ask “jamesh” to ask Simon Martin for you (design lead for the product) - I’m sure it’s not a trade secret, haha

memberlist.php?mode=viewprofile&u=281376

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 29059
Joined: Sat Jul 30, 2011 7:41 pm

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 11:39 am

The actual part is from a specialist supplier so it will not be possible to buy just one part from them.

This part should work as an alternative.

https://uk.farnell.com/hirose-hrs/fh12- ... dp/2427721

When hand soldering these, care must be taken that any accidental solder bridge does not "wick" into the receptacle. It will be difficult to remove if it gets inside.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Working in the Application's Team.

David1
Posts: 14
Joined: Mon Sep 30, 2013 2:43 pm

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 12:36 pm

Thank you, Jamesh! It is just my luck that the 'ordinary looking' part I need is a specialist one! But I will try the one you suggest.

Fortunately, Mouser and Digi-Key which both have Canadian offices, have hundreds of these HiRose connectors in stock. Yahoo! I think there is some light at the end of the tunnel.

When I get done, I'll post an update. The success will depend as much on my skill (or lack thereof) at SMD repair as much as the 'fit' of the part itself.

Thanks to everyone who contributed.

David

electronicstoday
Posts: 41
Joined: Fri Nov 15, 2019 4:02 am

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 6:09 pm

jamesh wrote:
Wed Jun 16, 2021 11:39 am
The actual part is from a specialist supplier so it will not be possible to buy just one part from them.

This part should work as an alternative.

https://uk.farnell.com/hirose-hrs/fh12- ... dp/2427721

When hand soldering these, care must be taken that any accidental solder bridge does not "wick" into the receptacle. It will be difficult to remove if it gets inside.
Please specify the actual part and supplier, I have many industry contacts, thanks.

jdb
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 2615
Joined: Thu Jul 11, 2013 2:37 pm

Re: Replacing keyboard connector on motherboard

Wed Jun 16, 2021 9:40 pm

electronicstoday wrote:
Wed Jun 16, 2021 6:09 pm
jamesh wrote:
Wed Jun 16, 2021 11:39 am
The actual part is from a specialist supplier so it will not be possible to buy just one part from them.

This part should work as an alternative.

https://uk.farnell.com/hirose-hrs/fh12- ... dp/2427721

When hand soldering these, care must be taken that any accidental solder bridge does not "wick" into the receptacle. It will be difficult to remove if it gets inside.
Please specify the actual part and supplier, I have many industry contacts, thanks.
I'm intrigued. In what way does your "having many industry contacts" help the OP to fix a Pi 400 with damaged keyboard connector?
Rockets are loud.
https://astro-pi.org

electronicstoday
Posts: 41
Joined: Fri Nov 15, 2019 4:02 am

Re: Replacing keyboard connector on motherboard

Thu Jun 17, 2021 12:13 am

jdb wrote:
Wed Jun 16, 2021 9:40 pm
electronicstoday wrote:
Wed Jun 16, 2021 6:09 pm
jamesh wrote:
Wed Jun 16, 2021 11:39 am
The actual part is from a specialist supplier so it will not be possible to buy just one part from them.

This part should work as an alternative.

https://uk.farnell.com/hirose-hrs/fh12- ... dp/2427721

When hand soldering these, care must be taken that any accidental solder bridge does not "wick" into the receptacle. It will be difficult to remove if it gets inside.
Please specify the actual part and supplier, I have many industry contacts, thanks.
I'm intrigued. In what way does your "having many industry contacts" help the OP to fix a Pi 400 with damaged keyboard connector?
By way of being able to source once for them. You don't know me nor anything about me, nor whom or what I know, or have access to. Never assume.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 29059
Joined: Sat Jul 30, 2011 7:41 pm

Re: Replacing keyboard connector on motherboard

Thu Jun 17, 2021 9:01 am

I think this thread has an excellent chance of going downhill fast.

I don't have access to the specific part number/manufacturer data, and the one above should do the job.

So closing.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Working in the Application's Team.

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