Re: Hisense F42K20E Hum
I've never tried that on pins that small and close together. Is it just running the tip across them to heat them up?
revenerd
Member
Last Activity: 11-14-2022, 02:45 PM
Joined: 09-21-2022
Location: Yellville, AR
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Re: Hisense F42K20E Hum
Yes, there is a pad on the underside of the CPU heatsink.
I removed the soldered on metal cage around the CPU chip and removed the heatsink. I cleaned around the CPU with alcohol and a toothbrush, saturating the area well. I allowed it to dry then reconnected. The hum and click was still present but drastically reduced. I connected a video source and when audio was playing, the noise was imperceptible. I reassembled everything.
After reassembly, I conned a source and started playing video. It was normal, however, after a few...Leave a comment:
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Re: Hisense F42K20E Hum
The digital out is clean audio. I also noticed the left side of the screen is slightly darker than the right, it's almost imperceptible. If any of this could be related.Leave a comment:
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Re: Hisense F42K20E Hum
Unfortunately, my knowledge, experience, and tools do not go that far....Leave a comment:
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Re: Hisense F42K20E Hum
I disconnected everything I could. I also unscrewed the boards from the panel and placed a rubber mat under them to see if was something coming through the chassis. Even with the speakers disconnected, the sound comes through the headphone jack.
I checked the cap C70, it looks ok. No different that the others.Leave a comment:
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Re: Hisense F42K20E Hum
Buzz is still there after disconnecting TCON. Also attaching TCON board picture....Leave a comment:
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Re: Hisense F42K20E Hum
There is an inductor on the power board I can hear buzzing. It is located to the right of the long cap on the power board and is labeled LEI-302B.
Could that be the issue?Leave a comment:
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Re: Hisense F42K20E Hum
Attached is a recording of the noise. The pop is when the 'No Signal' text moves on the screen....Leave a comment:
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Re: Hisense F42K20E Hum
I have a little more time to look at this issue. The sound IS more static-like than I remembered.
When powering on with no devices connected, I get the blue screen with the words "no input" jumping around. The words are motionless, then jump to a new location. On each jump, I hear the static.
Any change on the screen results in the static sound. I.e. When the numbers change while adjusting the volume, pressing mute, changing the channel, moving around in the menu.
I muted the TV and the static sound is...Leave a comment:
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Hisense F42K20E Hum
With the TV on and not connected to any inputs, I get a hum. Increasing, decreasing, or muting the volume does not change it. It hums through the headphones as well.
The hum slowly and slightly goes up in pitch, then comes back down. On the blue screen, a click is heard every time the words "no signal" moves.
If I connect a device to the HDMI port, the hum gets much louder. The video's audio still plays and if turned up enough, it drowns out the hum.
I read the thread about this model and a static noise. I listened to the audio and it is... -
Re: New Members - please post your introductions here
Hi! I'm a Youtube and Forum Uncertified Repair Technician. Most of the time I don't really know what I am doing but I can follow instructions and have a great time learning.Leave a comment:
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