Thanks that's what I was hoping. Both replaced and after PAT testing them, the speakers are now back in a classroom ready to be used.
Thanks also for the feedback on the capacitors, I do try and by Panasonic or Rubycon when available but I'm limited to places like CPC or RS Components and their minimum order cost before free delivery etc. - feedback like this is genuinely always appreciated....
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Both ICs were replaced (along with the 2 large powerline capacitors which were swollen) and the speakers are now working coreectly.
I have another set of speakers in for repair (like busses they keep on coming) and they have similarly numbers AMP ICs:
[ATTACH=JSON]{"alt":"Click image for larger version Name:\t20241111_133057147_iOS.jpg Views:\t0 Size:\t1.78 MB ID:\t3504845","data-align":"none","data-attachmentid":"3504845","data-size":"custom","height":"480","title":"20241111_133057147_iOS.jpg","width":"640"}[/ATTACH]...
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Reflow training.
How do you get experience of reflowing ICs when you have no ICs to reflow - the answer is to reflow things and learn from it. Just like soldering, how do you practive soldering, you solder things. How do you learn to drive a car, you drive an actual car. How do you learn to play a piano, you practice on a piano no matter how badly someone like yourself tells you you're rubbish and need to play better - how can you play better without playing badly to begin with and practice to make perfect?
How would you suggest I learn to reflow IC's - watch youtube...
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Here you go!
[ATTACH=JSON]{"data-align":"none","data-size":"custom","height":"394","title":"LM1875T.png","width":"654","data-attachmentid":3495927}[/ATTACH]
[ATTACH=JSON]{"data-align":"none","data-size":"custom","height":"407","title":"LM1875T-NOPB.png","width":"651","data-attachmentid":3495928}[/ATTACH]Here you go!
[ATTACH=JSON]{"data-align":"none","data-size":"custom","height":"394","title":"LM1875T.png","width":"654","data-attachmentid":3495927}[/ATTACH]...
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I've just had a look on CPC's website and they sell 2 different LM1875 ampliers:
[url]https://cpc.farnell.com/texas-instruments/lm1875t/ic-amp-audio-20w-1875-to-220-5/dp/SC18488?st=M18%20BH-0[/url]
[url]https://cpc.farnell.com/texas-instruments/lm1875t-nopb/ic-op-amp-single-70khz/dp/SC18489?st=lm1875[/url]
The 25W one is cheaper than the 20W one by nearly 50% - I believe the TDA2030 is 14W so are either of the above a good replacement or would the 20W one which is closer to 14W be the better choice out of the two?I've just had a look on CPC's website and...
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The TV was replaced 2-3 weeks ago so this was purely a learning/training exercise - even if it had been successfully repaired, there is currently no use for this TV and £24 for a couple of days self learning/training a 12 year old TV worth bugger all is a bargain as any kind of training course would cost more than double that per hour!...
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Thanks I'll bear that in mind for the future (I've added it to my repairs notes I keep in Microsoft OneNote).
Is there any specifics I should look out for when purchaseing some white thermal grease or is any one from an electronics repair distributor (like the one in this link) OK?
[url]https://cpc.farnell.com/kontakt-chemie/33392/silicone-grease-50g/dp/SA04194?st=silicobne[/url]
The capacitors were not very happy so I have replaced them already! They were both very swollen. Working in a school they keep these speakers on 24/7 as if...
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TDA2030A Audio Power Amplifier Question
My boss always says "[I][B]the only stupid question is the one not asked[/B][/I]" so at the risk of asking a stupid/obvious question I'm going to one any way...
I've got a pair of speakers with an amp built in to them in for repair and on inspection I can see the TDA2030A amplifier ICs have blown (so I've ordered some spares which should arrive soon):
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3495156}[/ATTACH]
My quesion is with regards to the white paste you can...
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My hand shook when attempting to reflow the driver IC and a couple of solder balls appeared to the side of the IC so I killed it - all adding to experience as like I say, these small BGA chips were not around on the TVs I repaired 25+ years ago at College.
At the end of the day for £24 I got two days of experience and knowledge of how a modern day TV works compared to the old CRT ones and the comments from all you guys in invaluable to me - much better than any expensive training course. I've kept what I can for spares and labelled the board and LEDs up with the make/model of TV...
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RIP LG TV
My repair journey with this TV is now at an end and I will be stripping it for parts and putting the rest in the WEEE/eWaste.
I did however manager to get one of the two pairs of speakers working that I also had come in from a classroom so 33% success rate today!
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100% going to give that I try - I've reflowed a few IC's in the past that has solved issues - it certainly wont make it any worse and if it does fix it then that's another piece of knowledge in the bank!
I wish they hadnt lost the remote control as navigating the menus with the buttons on the back is a pain!! I will give that a go though.
Constructive critism is always welcomed as how else can someone increase their knowledge and experience?! Thank you all who have replied, much appreciated. I'll update the thread with what I do next...
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Limited Space + TV In Bits + Delicate Screen = Need To Sort Something Out Quick before it gets damaged!
Working in Education there is no money for training so on-the-job training like this is how we have to learn new skills and gain experience.
The TV was going to go in to WEEE/eWaste and the LED strips that had the exact model number listed in the listing cost £24 and I have learnt how a modern TV works (the last time I repaired a TV was at College 20+ years ago and they were CRTs)! I've learnt that a backlight repair is a relatively easy repair and that you should...
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The strips I got were not LG branded just some generic brand that happened to be in stock on Amazon for next day delivery - my thinking was that LG branded ones already in the TV would be better so kept the working ones in. I've since put all the ones I got from Amazon in the TV and it still pulsates when I connect the screen. No idea if it's been doing this previous to the LEDs failing as it's used for digital signage and they may not have noticed....
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I've replaced all the remaining original LG LED strips with the ones I have and it's still doing it.
I have perservered with the buttons on the back of the TV and after lots of pressing the wrong buttons I managed to navigate the menu to the BL setting and even on 0 you could see it flickering.
What I shall have to do is put all the working original ones back on the TV and then the 2 faulty strips I'll have to try bodging a repair by scratching off the tracks and bypassing the faulty LEDs and see if there are any dark spots on the TV - it is perfectly possible that its...
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Reception have lost the remote control so changing any levels is awkward with the limited buttons on the rear of the TV!
I haven't replaced all the LED strips, just 2 of them so I might remove all of the other original LG ones so they are all the same - do you think that might help?...
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Just found a USB memory stick and put a photo on it and it's still doing it but it's not quite as obvious:
...
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Without HDMI plugged in I get a spinning LG logo that doesnt quite go over to the left hand side where the pulsating occurs but I can't see any pulsating.
[EDIT]
I've just turned it on and got a menu up and yes I can see pulsating on the left hand side when nothing is connected to HDMI - I've also just tested it on the other HDMI port on the back rather than the side and sadly the pulsating is still there.
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LG 42LN540V LED Backlight Flickering After Replacement When Connecting The Screen
This TV has been on the wall in our reception area for around 10 years and the other day the backlight failed. You could see a feint picture so we knew the screen was OK. I took the TV apart to get to the failed backlight and inject voltage in to each half of the LED strips to identify which ones had failed and 4 needed replacing. I ordered a set off of Amazon and they arrived the next day.
On fitting the new LED strips I plugged in the TV was blinded by the light!!
[URL=filedata/fetch?filedataid=357626][ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3490560}[/ATTACH][/URL]...
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