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| Test Equipment Anonymous (TEA) group therapy thread |
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| Vince:
TV REPAIR OK made some progress. Took the thing completely apart, LCD is gone, and it's sitting upright on itsedge because nowhere to lay it flat. If that damages it, too bad for him, I can't invent table space that I don't have... So now I can see inside this thing and... uh oh.... where are the fucking LEDs, there are none ?! :wtf: Oh.. I see.... assumed somehow it must be lie the previous TV I fixed, that had an array of LED covering the entire chassis... well no, this newer TV has no array, it's lit only from the edge, and only one single edge at that ! :o Well, it that works, I guess why not... So now we can see we have indeed 4 independent strings, and no resistor that I can see to equalize the currents between the strings that are //, so I guess no surprise that they blew eventually... They cut the PCB in two. Eeach bit carries therefore two strings and a 4 pin connector. Each string carries 20 LEDs. I immediately found a dead LED in the right half of the screen, the half that didn't work, so I was happy. Was easy to spot... it's was brown / cooked... Buzzed it with the DMM because somehow '"at rest " they drop only 0.7V. I guess the typical 3V drop is only valid once they lit up and suck lots of current. One has to scrape the white solder mask to reveal the copper so s to make contact with the DMM probes, but it's not too bad of a job. So I could confirm that that LED was dead, open circuit. So I Widlerized it with side cutters, just because, then a BC558A agreed to sacrifice and donate one of its leads so I can use it to bridge the gap where an LED used to reside. Then I plugged the TV to see what I get. Luckiiy the digital board is kind enough to accept to light up the screen even in the absence of the LCD panel... NOw the strip with the dead / bridged LED lights up, yeah !!! :-+ But... it's sister string, the last one to the right... does not. So I guess there must be at least one open circuit LED in that string as well. Also, the first two strings / Left half of the screen, that used to work... well now one of the two strings is dead now ! :palm: So now instead of having the left half of the panel that light up, I have now alternating stripes of lights, as you can see. OK... more work required.... but looks like I am making progress. I can't call it an "improvement " just now since it's one step forward and one backward, but I think at least I can call it " progress ", what do you think... So now nee do a lot of scraping so I can test all the LED's in these two dead strips, and find the dead ones.... EDIT : well we did at least now prove that the power board / LED driver was indeed fine, which was still an hypothesis / educated guess just an hour ago.... so yeah, we did at least "improve" in the "diagnostics" department, short of improving in the "fixing" department just yet.... |
| Specmaster:
--- Quote from: bd139 on July 06, 2022, 03:10:52 pm ---<snip> I don't agree with speed cameras being removed. They are quite effective. However cyclists yep. At least here they have a few strategically placed fuzz who take quite a few out for red light jumping. When I was working down in Farringdon it used to be a favourite morning activity to step out in front of them and then cross really slowly so they had to dismount rather than squeeze by. One of them had a right go at me and the person in the car opened the window and called him a "sweaty cracked cunt" which ended the argument with laughs. Note I was a cyclist as well and I never did that and didn't ride on the pavement at all unless it was marked up that I could. --- Quote from: Specmaster on July 06, 2022, 02:54:03 pm ---I hope you all haven't eaten all of your popcorn yet, or perhaps you'd better stock up quickly, things are developing at a fair rate of knots and there could be some big announcements coming up in the not too distant future ;) ;D --- End quote --- It's the omni-shitshow! --- End quote --- Agreed with the cameras they are quite good, trouble with them is however that there are many that are tucked away in locations where you cannot see them until the last minute, and they are usually the ones located just where the limit changes from say 40 to 30 and are designed to catch people in the process of actually slowing to new limit, the sign of which is also pretty well hidden until the last minute. That is another reason why I have the TomTom satnav as their database has the speed limits for most of the roads, and it will warn you as you approach the area where the limit change, if you're driving too fast, and also of course alert you to the speed camera, and display the speed limit. The other good thing about them is of course when you're in a average speed zone, they calculate and display what your average speed is, so you can overtake safely if you know that your average is within the limit. :-+ What I don't agree with is the current apparent reliance on cameras alone for policing the roads. Regards the omni-shitshow!, it stands currently at time of this post, 32 resignations and a possible further 6 expected today and maybe more in the wings, this could be quite entertaining in its own way, I might stock up on a few beers as well :popcorn: :popcorn: |
| Zoli:
--- Quote from: Vince on July 06, 2022, 04:04:32 pm ---TV REPAIR ... So now nee do a lot of scraping so I can test all the LED's in these two dead strips, and find the dead ones.... --- End quote --- If any of your multi-meters that would lit the LED's up, that would be a great help; especially if you have sharp tips, like the Pomona 6275 :-DD :-DD :-DD /enabling |
| Specmaster:
--- Quote from: Vince on July 06, 2022, 04:04:32 pm ---TV REPAIR --- End quote --- Make sure if you are able to resurrect the other strings, that your friend is well aware that he might actually spot areas of his screen that are dimmer than others, in the areas with the dead LEDs, otherwise he might not be happy with you. Short of replacing all the strings, I can see no way around that problem. Great work so far, keep it coming. |
| Cerebus:
--- Quote from: Specmaster on July 06, 2022, 04:11:12 pm ---Agreed with the cameras they are quite good, trouble with them is however that there are many that are tucked away in locations where you cannot see them until the last minute, and they are usually the ones located just where the limit changes from say 40 to 30 and are designed to catch people in the process of actually slowing to new limit, the sign of which is also pretty well hidden until the last minute. --- End quote --- Well, if one isn't speeding, who cares where the cameras are? And if one isn't observant enough to spot a speed limit sign or a bright yellow speed camera in a reasonably predictable place on the road in enough time to react to it safely then one certainly isn't observant enough to be in adequate control of a vehicle that is being driven over the speed limit. A traffic sergeant I used to know said he never ticketed people for mere speed, but for failing to spot that a police car was behind them when they were speeding or sitting at the side of the road while PC Plod was standing next to it in high-vis with a RADAR gun in his hand. |
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