Crumbling T-con cable wires on an LCD - Page 1
Forum section: electronics / repair

author: matt6ft9
author_rank: Contributor
timestamp: March 07, 2015, 12:20:49 am
content: Hi, I'm trying to save a small LCD TV from the trash heap. The TV is a Philips, model15pf9936/37 and is about 10 years old.I've tracked the problem down to a disintegrating T-con cable. See picture below.Outside of a hot environment, extreme age, or lots of vibration, I've never seen wire insulation crumble like this.There are no markings on the cable. The “bad” side has a roughly 3 inch long ground strap with a round terminal lug on the end.Both sides of the cable have 1mm pin spacing. I've looked on ebay to find a replacement, no luck.(even if I were to find one, it might be crumbling too) Digikey and Mouser have not been any help either.Below is a closeup of the "crumbly" side.Any idea's on how to get/make a new cable?Matt

author: Spyke
author_rank: Contributor
timestamp: March 07, 2015, 12:48:32 am
content: That one looks pretty salvageable with something like kapton tape or heatshrink tubing.The one in my Dell 3008WFP was pretty destroyed.I originally opened it up to replace the D22 Schottky diode (common problem), only to have the T-Con cable disintegrate...Needless to say I found another T-Con cable from one of my junked computer monitors, took the plugs off the end and wire for wire replaced all 24 wires of the cable to the old cables T-Con header. Luckily the T-Con header had an inch or so of good wire left to solder to. I also lucked out on the fact that the end plugs that go into the main PCB used the same type of pins as the new cable so I simply transferred them over to the old plug casings. The worst part about the whole thing was removing the black sheath of the old cable, to completely map the pinouts of the LVDS pairs. The entire thing inside the sheath was also crumbling to nothing...Some pics, old cable in the last image.https://imgur.com/a/POruc

author: Shock
author_rank: Super Contributor
timestamp: March 07, 2015, 12:57:17 am
content: Looks like the insulation has failed, google to see if it is a known issue. If so call it a manufacturing fault and contact the Philips you might have success in getting them to send out a replacement, or try the same with a service agent.

author: matt6ft9
author_rank: Contributor
timestamp: March 07, 2015, 12:48:59 pm
content: The kapton tape or heatshrink tubing is a good idea. The wire pairs are twisted together, which might make the kapton tape wrap of each wire difficult. I'll have to see if I can remove the pins from the connector.I was not able to find anything about crumbling insulation being a manufacturing fault from Philips.

author: amyk
author_rank: Super Contributor
timestamp: March 07, 2015, 03:41:52 pm
content: That is unusual - I guess it was either runningveryhot, or if the insulation cracks near the middle too and not just where it goes into the connector, it could be the result of some solvent they used that reacted with the insulation or a defective batch of plastic. When plasticisers migrate out of plastics this usually happens.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: March 08, 2015, 04:10:13 am
content: Geez what were you watching on that TV?

author: G7PSK
author_rank: Super Contributor
timestamp: March 08, 2015, 09:52:41 am
content: I would just slice the outer open and replace each wire in tun by cutting it off at each end with a couple of mm of wire left and soldering a new wire on, then insulate the soldered bit, a short piece of shrink tube over the wire before soldering is best.Then wrap the whole harness with tape when finished. If the insulation is that bad at the ends it is unlikely to be much better under the sleeve so replacement of the whole wire is best in the long run.

author: Spyke
author_rank: Contributor
timestamp: March 09, 2015, 01:35:39 pm
content: The CCFL backlights and inverters on older monitors/tv's ran ridiculously hot so the LVDS cable insulation was very likely ran out of temperature spec, at least in my case all but the last 1 inch of the cable was ruined.Its more likely in your case someone had a crack at repairing the TV, as you would have to disturb these cables years later to have the insulation all flake off like that.

author: matt6ft9
author_rank: Contributor
timestamp: March 11, 2015, 02:46:29 am
content: Success! G7PSK you're awesome. I took your advice and replaced the wires with wire wrap and then heat shrunk both ends.It took a couple of hours (I'm slow at soldering fine wire), but the TV is now operational.(see pictures, for the cable and operational TV)Spyke, you're probably right about someone trying to repair the TV. The TV draws about 40 watts.

author: tom66
author_rank: Super Contributor
timestamp: March 11, 2015, 11:50:10 am
content: Nice fix!