How to extend a laptop LCD cable? - Page 1
Forum section: electronics / beginners

author: idoit
author_rank: Contributor
timestamp: December 14, 2021, 12:41:20 am
content: Hi everyone,I have a laptop LCD cable that is short and I want to extend its length (image #1 right side). There is a "FFC connectorA" on the left and FFC atBshould connect there, but as cable is short, I need to add a FFC fromAtoBto connect them. And eventuallyDshould connect to a FFC connector on the laptop motherboard. Which is also further away from it and therefore, I should add a FFC cable and connector here too!I think I have two options:1. Cut the wire at the red spot... find another cable of desired length and count of thin wires (32) and try to solder the two ends of this new wire to the two ends of cut wire at pointC.2. Buy a long FFC with same pitch and count of pins as the end and use ffc connector to connect A to B and D to motherboard.Option two seems to be the easiest BUT here's a constraint: all these cable have to go through a hole that is less than 1 inch and they'll be moving around... so a 32pin ffc connector would not fit.I'm assuming option one is very tedious if at all possible, but if it is, it's surprisingly the cleanest!What is a good way to extend my LCD cable in this case?For option 1: can I make use of the thin wires that are found in headphones? (image #6)For option 2:- Is there another way with thinner profile? Like I said, ffc connector can not move through a 1 inch hole, on an every day use scenario. Can I somehow glue them in a way that the pins perfectly get aligned and never move?! (image #2)- Where can I buy a ffc cables that is bundled like image #5 ? What are they called?Thank you for your inputs!

author: ledtester
author_rank: Super Contributor
timestamp: December 14, 2021, 03:15:49 am
content: Quote from: idoit on December 14, 2021, 12:41:20 amYou can get FFC breakout boards for cheap, e.g.:https://www.aliexpress.com/item/33005592334.html

author: idoit
author_rank: Contributor
timestamp: December 14, 2021, 03:31:56 am
content: Thanks for your response. I actually thought about it, but like I mentioned, I don't have much space for a break-out board and its thickness would make fitting even more challenging.- What does the inside of these LCD cables look like? (My search yielded not much) 32 really thin wires? Not possible at all to cut the cable in half, add desired length and solder them and extend the cable that way? (I am willing to put a lot of work and patience in this)- Can I use the very thin earphone wires, 32 of them, to make this LCD cable? or its resistance etc would be problematic, heating, fire hazard etc. Sorry I'm an electronic newbie!

author: ledtester
author_rank: Super Contributor
timestamp: December 14, 2021, 05:39:06 am
content: You might be interested in what this guy did:https://www.yars.org/kc6uds/gtx-remote-head.html(web archive link)He soldered a 25 conductor serial cable (a "DB25" cable) to a flat-flex cable.Besides a DB25 cable you could look at using a Centronics printer cable -- that's what was used to talk to printers before USB came around. You can still buy them. In the US they still pop up with some regularity in thrift stores (i.e. Goodwill, Salvation Army, ...) I'm not sure but it is possible that a Centronics cable has upwards of 36 conductors.

author: idoit
author_rank: Contributor
timestamp: January 23, 2022, 04:44:49 am
content: Thank you for your responses. I'm back with one more question.I have attached a piece of schematic for the LVDS connector. I want to minimize the number of wires in it (that I am intending to extend). As you can see the connector has 28 pins; well it has 30, two for the GND legs (or whatever they are called in connectors) that get soldered to the motherboard. I guess I can ignore those two.I have opened up the cable and it actually only has 24 thin wires as there are no wires for pin 5, 15, 18 and 21 (even though schematic shows that pin 15, 18 and 21 are GND).So that leavespins 1, 11 and 12. Can I reduce them to just one wire? or it affects signal integrity?If I can reduce them, what would be the best configuration with least number of wires? I have attached two configs that came to my mind. Are any of them possible? If so, that'll reduce the thin wires that I have to run from 24 wires to 21 wires (which is great).I'd love to hear your opinion. Again, I have not studied electronics, so sorry if it's stupid question.P.S. Even if I can just replace wire 11 and 12 with just one wire, it'd be good. But please let me know the best config possible. Thank you!