Re: Unknown component: Diode or zener?
Beautiful!
Thank you
Where do you recommend getting schematics like the one you shared?...
Vincenzo2
Member
Last Activity: 11-11-2023, 02:55 PM
Joined: 10-25-2022
Location: Pennsylvania
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Re: Element 32 inches tv (ELEFW328B) Unknown component: Diode or zener?
Thanks. Missed that one....Leave a comment:
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Re: Unknown component: Diode or zener?
Thank you. Great information. I measured the low voltage both with LEDs connector connected and disconnected.
I just did it again. Connected to mains and off (standby), 24 volts and some change, Turned ON, 27 volts and some change and very quick jumps to 90 volts and then goes down quickly to 28v and change.
Can you give me the general LED's connection (every strip is series, or some other configuration)?
Does one bad LED turn of that protection circuit you mentioned? or does it have to be severe enough?...Leave a comment:
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Element 32 inches tv (ELEFW328B) Unknown component: Diode or zener?
My Element 32 inches tv (ELEFW328B) lost it's backlight (confirmed with a flashlight test) and the connector on the PCB (it has one board that has a processor chip, switch mode power supply, and backlight circuit) that has the two wires that go to the backlight LED strips has a very low voltage (28-29 volts) when turned ON, in my opinion.
Started testing components and found an SMD diode or zener that is shorted (even zero fusing resistors read a few tens of milliohms, while this thing reads zero).
I put some pictures here to show that it is labeled "M7".... -
Re: New Members - please post your introductions here
Howdy. Vinny from Central PA here. Been away for a while.Leave a comment:
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Re: ebike charger Component Function (for replacement)
I did have a similar feeling that the guy wasn't very accurate. I am not repairing it for money, it is more like a challenge. After further inspection with a meter I found a tiny (what looks to be) general purpose transistor in a small aggregate of components that look like a little sensing or protection circuit that has the central pin shorted to one of the side pins (shown, back of main board, and enlarged).
That, assuming that it IS a transistor. I use [URL="https://smd.yooneed.one/"]this[/URL]...Leave a comment:
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Re: ebike charger Component Function (for replacement)
this is the little protection add-on that should not be larger than a matchbox (in dotted line)....Leave a comment:
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Re: ebike charger Component Function (for replacement)
Thanks much.
The reason I was in doubt with my guess was that this "protection" component did not prevent the little explosion and did not protect the main switching components.
The charger owner wanted me to come up with a polarity reversal protection addition to the charger and gave me permission to drill anywhere in the enclosure if a need arises. My first thought was using one of those fuses that look like a little push button (photo attached). Then, I thought, to avoid counting on...Last edited by Vincenzo2; 10-25-2022, 11:54 PM.Leave a comment:
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ebike charger Component Function (for replacement)
I have a fancy (around $400) 72V 1500W ebike charger that was connected to a battery in reverse polarity. There were two high specs MOSFETs on large heatsinks that blew up to pieces.
I ordered the MOSFETs from digikey and inspected the few other large components near the outputs and there was still a short.
My suspects were two MOVs that were not short, 680uf/100v 3 parallel caps that measured good (capacitance, leakage, and ESR), and finally a small SMD diode that had a crack and when inspected off the board was shorted.
This diode is connected...Last edited by Vincenzo2; 10-25-2022, 02:24 PM. -
Re: New Members - please post your introductions here
Hello
I just joined this forum after hearing about it a few times through the years. I guess it is the best in this field (even more so than EEVBlog) after being a reference for 19 years.
I have been in electronics since I was a child (i.e. from the late 1970s) and did undergrad and grad degrees in EE in the 1990s and worked in component level repair (did design, reverse engineering, and manufacturing a few times) for a while but recently rediscovered repair working with a microscope (i guess they call it microsoldering)...Leave a comment:
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