- backlights #2 - 2 Updates
- backlights - 2 Updates
| kayge <kgpupswitch@gmail.com>: Sep 01 08:53PM Well, well, aren't you sharp! I'm going through the backlight chain one by one INCLUDING connectors. The originals were 5 strips of 10 LED's, but the replacements are 10 strips of 5 tied by a connector. Sure enough one of the lines wasn't making it through one of the connectors. I will go through the rest of the chain tomorrow and repair any breaks. My friend will be super happy if I fix this as they aren't terribly well off. Just curious, where are you from? North Florida USA here. |
| "ohg...@gmail.com" <ohger1s@gmail.com>: Sep 02 09:32AM -0700 On Thursday, September 1, 2022 at 4:53:29 PM UTC-4, kayge wrote: > through the rest of the chain tomorrow and repair any breaks. My friend > will be super happy if I fix this as they aren't terribly well off. Just > curious, where are you from? North Florida USA here. I'm in Wolcott Connecticut. I have seen a lot of those interconnects cause problems from flickering to no function at all, but never on new strips. I have a feeling you ended up with pulls. There should be zero resistance across the connectors. After you fix the bad one make sure they ALL are zero ohms. If any are a few tenths of an ohm or higher, jump them all out with short insulated wires, otherwise you'll be back inside at some point. Even if they test good with an ohmmeter they may show some voltage drop across them. There of course should be 0.0V drop across the connectors. If this TV has a back light adjustment in the customer menu, lower it to just above half to preserve the LED array. If it doesn't have an adjustable setting in the menu, let me know and I'll show you what resistor to change to lower the global current. |
| kayge <kgpupswitch@gmail.com>: Sep 01 07:35PM Again thanks for the help. Dummy me, test all the new back lights individually and assume that problem is solved. WRONG! Upon plugging the power cord in, no flash. Stuck my trusty meter on XP702 and it initially goes over 200V, then peters out a few volts per second like there's no load whatsoever. It appears to be draining slowly into the power supply. Time to take all the screens apart again and find where the break is. |
| "ohg...@gmail.com" <ohger1s@gmail.com>: Sep 01 01:37PM -0700 On Thursday, September 1, 2022 at 3:35:36 PM UTC-4, kayge wrote: > goes over 200V, then peters out a few volts per second like there's no > load whatsoever. It appears to be draining slowly into the power supply. > Time to take all the screens apart again and find where the break is. That's why I don't reassemble until the LEDs run an hour. The more the screen comes apart, the greater the likelihood it won't survive another attempt. Look for one of the plugs not fully seated (I've done that a bunch of times). General comments on display removal: be very careful with the bonded ribbons - try not to flex them much. If the display is held down with double sided tape, make sure to carefully life the screen out. I use a heat gun (carefully) to heat up each side one by one, and with a small suction cup, pull up while sliding a thin plastic shiv along working until the side is free. I then put some paper towels on the released side so it doesn't rebond when you move to another side. If you try to lift the screen without releasing the tape, the screen WILL crack. Make sure those sheets go back *exactly* as they came out. If you get one upside or backwards or out of order, it will affect the picture as at least one of the sheets is a polarizer. Make sure the four corners of the display itself are safely nestled inside the frame. You can use a combination of feel and magnification if necessary to make sure the screen isn't sitting on the lip even by a micrometer. If the display isn't tucked properly inside the frame, it WILL crack when you snap the outer mask back in place. |
| You received this digest because you're subscribed to updates for this group. You can change your settings on the group membership page. To unsubscribe from this group and stop receiving emails from it send an email to sci.electronics.repair+unsubscribe@googlegroups.com. |
No Response to "Digest for sci.electronics.repair@googlegroups.com - 4 updates in 2 topics"
Post a Comment