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unimatrix93 started a topic LG BH6420P Home theather blue ray player repair

in Troubleshooting TVs and Video Sources

12-10-2024, 10:31 AM
LG BH6420P Home theather blue ray player repair

Hello everyone, I'm trying to troubleshoot this LG hometheater player.

The customer forced her USB drive reversed into it's USB socket and since then the player won't work properly, only shows "Please wait" error forever on it's display.

Now I started diagnosing the USB socket and the mainboard where it's connected.

I found 20ohm resistance to ground on the 5V line of the USB.

5V is missing and I found the buck converter of the USB line, TPS65252 IC.
After measuring the pins I realized that both VIN and 3V3 is correctly present...

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

12-01-2024, 08:18 AM
I disassembled the froster to get to the temperature sensor and fuse.
Turns out both of them are good.
I decided to re check the main power board.
Turns out I made a soldering mistake at the heaters relay,(I replaced all of the relays to new ones) one of the coils leg were not soldered properly.
So I resoldered it and reassembled it into the fridge and the error is gone. The compressor is working and the fridge is cooling too. I wait until monday to test it before I completely reassemble it.

And I will return with the reports.
Thank you all and wish me...

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unimatrix93 replied to Which resistor should I remove/replace to decrease current to backlight leds?

in Troubleshooting TVs and Video Sources

11-29-2024, 05:51 AM
It's a Phillips 49PUS6550. The mainboard is 715G6973
....

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unimatrix93 replied to Which resistor should I remove/replace to decrease current to backlight leds?

in Troubleshooting TVs and Video Sources

11-29-2024, 05:24 AM
Good idea, but the tv doesn't have a setting for backlight brightness, only eco mode. 😅...

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unimatrix93 started a topic Which resistor should I remove/replace to decrease current to backlight leds?

in Troubleshooting TVs and Video Sources

11-29-2024, 05:05 AM
Which resistor should I remove/replace to decrease current to backlight leds?

Dear community, I want to increase the lifespan of my backlight led in my TV by decreasing the current.

However I need some help identifying the resistor I need to replace to achieve this.

Thank you!
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[URL=filedata/fetch?filedataid=363037][ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3517700}[/ATTACH][/URL]...

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-28-2024, 05:40 AM
This unit is around 25 years old and it served perfectly for it's lifetime. We love this fridge and altough I looked around for a new unit in a case of impossible repair, but those that have similiar attributes are incredible expensive. Even on the aesthetics are perfect for my kitchen. All of the current fridge are industrial looking, plain steel or black colored. At least here in Europe I cannot find anything that even similiar and doesn't cost €1000+.
I really want to repair this fridge if it's possible.

Here is a photo of the compressor:
[ATTACH=JSON]{"dat...

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-28-2024, 03:16 AM
Thank you for your help and patience everyone.
So I ordered new relays, I tought its better to replace all.

After replacing the relays the fridge compresser started right up and started cooling down both the freezer and the refrigator.
This happened last night.

Now this morning I noticed that the display showing this error code:
[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3516929}[/ATTACH]
The display does not respond to any presses, nor opening the doors.
Altough...

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unimatrix93 replied to E-Scooter battery not charging.

in General Electronics Technical Discussion

11-26-2024, 02:29 AM
Thank you for the detailed answer.

I discharged the scooter to the level where it won't provide power to the motor. It's at 2% according to the display when I connect the charger.

It won't charge by it's original charger, it shows the charging animation but the % never goes up.

I can charge it by connecting my lab PSU to the discharge plug. Then I connect the original charger and the percentage start to rise to the level where my lab psu charges up. The problem is, that when the charge drops, you cannot charge it with original charger....

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-26-2024, 02:13 AM
No, the compressor gets power for a second or two, then the relay turns off.
The other two pins, FAN H and Fan L getting power. Altough one of them getting 290V while the other 230, don't know if it matters.
As I mentioned, the relay does click when I plug in the fridge, delivering power to the compressor but it clicks again as it tursn of moments later.

I checked the PTC, the reading were 45ohm on room temperature, it should be okay since it's a 240V system here. Should I check If the resistance increases as I manually heat it?
I also checked the OLP next to it,...

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-25-2024, 12:02 PM
Here is some more tests:
i connected my DMM to the comp pin.
I noticed that as I plug in the fridge, the relay clicks, the voltage goes up then the relay clicks again and the voltage drops off to 0V. It happening in 2 seconds at max.

[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3514930}[/ATTACH]...

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unimatrix93 replied to E-Scooter battery not charging.

in General Electronics Technical Discussion

11-25-2024, 08:18 AM
I'm in the middle of doing it, I'm just very busy these days.

One question:
If the packs are inbalanced, can I balance the packs with me lab PSU without taking apart the whole thing again?
Or I have to balacne it cell by cell?...

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unimatrix93 replied to LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-25-2024, 04:46 AM
Thank you all for your inputs.

I dissassembled the motor PTC and the overload relay.
The overlay relay seems to be okay, but the PTC shows 45ohm resistance on room temperature....

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unimatrix93 started a topic LG fridge compressor not starting

in Troubleshooting Appliances and other Household Electronic Stuff

11-22-2024, 03:27 AM
LG fridge compressor not starting

Hello everyone, my old but loved LG GR-642 stopped cooling and frosting all together.
The display shows everything as normal, the focused cooling activated when I open the doors but the compressor wont start.

First I measured the terminals on the compressor at the back of the fridge. 0 volts.
Now I disconnected the compressor and measured resistance on its leads: around 8 ohms.

I dissassembled the main powerboard, couldn't find anything suspicious but I noticed that the comps relay wont send voltage to the pin, while Fan H and fan L is indeed at 230V....

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unimatrix93 replied to E-Scooter battery not charging.

in General Electronics Technical Discussion

11-18-2024, 10:25 AM
I reassembled the battery and started charging it with the original charger.

Now the battery did charge up to 9%, but now it stopped charging and the charger make this blinking every few seconds.
The battery is at now at 21.1V.
...

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unimatrix93 replied to E-Scooter battery not charging.

in General Electronics Technical Discussion

11-18-2024, 04:36 AM
Sorry for the long wait.
I replaced the faulty cells with new ones.
How close they should be in voltage? The new ones are 3.64v. I balanced the rest of the cells to 3.5V. Should I try to charge them to 3.6?

Thank you!...

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unimatrix93 replied to HP 14-DV0021NH not turning on

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-12-2024, 02:46 AM
Some progress:
I connected a HP adapter to my lab PSU and I plugged it in my notebook.
With battery, it does charge nicely: taking 220mA and slowly decreasing.

So the charging circuit and EC chip is probably fine.

Without the battery is does this and pressing the pwr button does nothing:

...

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unimatrix93 replied to HP 14-DV0021NH not turning on

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-11-2024, 12:04 PM
I just realized that these mosfets are P-channel mosfets. So the lower Gate voltage is correct, no?...

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unimatrix93 replied to HP 14-DV0021NH not turning on

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-11-2024, 11:33 AM
Turns out the first two mosfets has wrong gate voltage:
First mosfet has 6V and the second mosfet has 17V.
What could be the cause?...

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unimatrix93 replied to HP 14-DV0021NH not turning on

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-11-2024, 04:10 AM
Still no progress on the laptop. I thinking about trying to charge it with an USB C charger.
The charger IC's DC IN pin has only 17.9V. Bit low isn't it?

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unimatrix93 replied to HP 14-DV0021NH not turning on

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-07-2024, 08:10 AM
Sorry for being late, lots of work lately.
There is no schematic for this board, at least I couldn't find a free one on the web.
The charger IC is an [URL="https://www.alldatasheet.com/datasheet-pdf/view/897408/INTERSIL/ISL9238.html"]Intersil ISL9238.[/URL]

There is no silk screen markings other than the model number and such.

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