LF501EM5F No Power, Chirping/Beeping Transformer

[budm]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

10uF 25V MLCC.

[freakytiki4u]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

I am also looking for the part# and/or UF and Voltage Ratings for that Surface Mount Cap C3214. If anyone has that, it sure would be nice of them to post it here. I can find similar caps on ebay and I usually buy from Digikey but I don't know what Voltage and UF Rating to order. Post 137 only says its a 270 Pizo Cap but that's not all the info needed for someone like me who is not a certified repair person of your degree (Respectfully)

[R_J]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

See post #137

[Louis82]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Have you guys been able to find the Value or part number to order that cap location C3214?

Thanks!

[nwcs]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

I am having problems finding the main board for this tv for a sn starting with DS3, I did however find and order one from shop jimmy that is for a tv that starts with DS4 but they could not tell me if it will be compatible. Does anyone know if it will work for a magnavox 46me313v/f7?

[budm]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Measure the dcv between the two legs of the cap then double the value for the Voltage of the cap.
Ceramic cap common failure mode is shorted circuit.
The capacitance of the ceramic cap is affected by the applied Voltage (beside the temperature). So you must be careful as to what you choose to put in.
https://cdn.badcaps-static.com/pdfs/...1cafebd52c.pdf
http://www.murata.com/en-us/support/...mlcc/char/0005

https://ec.kemet.com/ceramic-capacit...tage-ask-fae-1


https://www.maximintegrated.com/en/a...ex.mvp/id/5527
From MAXIM notes:
'Note, first, that as the package size increases, the capacitance variation with applied DC voltage decreases, and substantially.
A second interesting point is that, within a package size and ceramic type, the voltage rating of the capacitors seems often to have no effect. I would have expected that using a 25V-rated capacitor at 12V would have less variation than a 16V-rated capacitor under the same bias. Looking at the traces for X5Rs in the 1206 package, we see that the 6.3V-rated part does indeed perform better than its siblings with higher voltage ratings. If we had looked over a broader range of capacitors, we would have found this behavior to be common. The sample set of capacitors that I was considering do not exhibit this behavior as much as the general population of ceramic capacitors.
A third observation is that, for the same package, the X7Rs always have better voltage sensitivity than X5Rs. I do not know if this holds true universally, but it did seem so in my investigation.
Using the data from this graph, Table 2 shows how much the X7R capacitances decreased with a 12V bias.'

[DrDigitalKC]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

UPDATE:
Fix confirmed.
Changing cap C3214 fixed the issue.

Original symptom:
The tv started "chirping" in cycles every couple of seconds on would not power on.

I have confirmed it is a blown cap on the main board location C3214.
Another tech here confirmed it as a 270pf cap, however voltage is not yet identified.
We ended up scrapping out a similar but smaller Emerson tv with a broken panel but similar main board. it had the same layout. I transferred C3214 from one board to another, and my LF501EM5F has life again!

We need to figure out the voltage of either the original or an acceptable replacement so we can either link to a replacement part or at least narrow it down for our next fellow tech to run across this issue.

[DrDigitalKC]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Go 1 step up on the voltage. Do not use the same voltage or the cap may go bad again. If it had a 16v use a 25v or higher. The voltage just means how many volts it can handle before it fails so the higher the voltage the stronger the cap.

This is good info... however I need to know the original value of said cap. I do not have, nor could I find the schematics for this board.
and yes, I did plan on upgrading the voltage tolerance.

[Shane711]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Go 1 step up on the voltage. Do not use the same voltage or the cap may go bad again. If it had a 16v use a 25v or higher. The voltage just means how many volts it can handle before it fails so the higher the voltage the stronger the cap.

[DrDigitalKC]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

C3214 is a 270 Pico cap btw.

I have this exact TV with the same chirping sound when plugged in.
I replaced a blown power supply about 8 months ago.
I've scoped out this power supply and cant find any bad components. I unplugged the ribbon cable from the main board to the power supply board and the chirping stopped. I'm certain the main board is the issue.

It seems to have been confirmed by you all that the problem lies with the C3214 cap on this main board.

The value is a 270pf...
What is the voltage?
I see several different ones available the most common being 50v.
I would guess that a 16v would do for this application.
Anyone have any idea or link to a good replacement part?

[JDC]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Confirmed: c3214 on main board replaced, TV works fine now.

[budm]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

C3214 is the MLCC (Multi Layer Ceramic Capacitor) brown rectangular shape SMD cap, right? So there is no polarity for that cap.

[fcisolutions]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

I have a Magnavox 46me313v/f7. I checked c3214 and sure enough it was shorted and fixed the problem Good Call. Also Budman I took your advise and got the LED Tester from SJ and it has already been a big help. It's pretty cool. Thank you both for the good advice!

Hey @martystv I have the same issue although C3214 and was trying to not only find a replacement cap but need help with polarity.

[fcisolutions]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

C3214 is a 270 Pico cap btw.

So I too have the same tv. Did you ever get a replacement part?

[Baron7]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

same symptom I fix change main board and work

[CapLeaker]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

OK, so in order to replace D614 with a better diode I need to know what the original is and then I would get one with a higher amp rating, right? I have no idea what it is.

And if I read your post I would understand that is to cut the traces on the board but I think you meant to cut the legs of the IC and then remove the IC and remove the legs from the board with a soldering iron. Yes, this is a good way to do it but for sure that IC will be trash after that ordeal. But I guess it is the best way and has to be done.

YES, I meant the legs off the IC, not the traces. Sorry, I was in a hurry to write this post.

If Kaboom would read this, he would be blastin me again.

[budm]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

If you look at the spec sheet of both diode, you can see the dimension spec.

[Shane711]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Are you saying it is bigger in size? That shouldn't be too hard. But I rather have one that would fit in the spot, not sure how to find it I guess. I expect it would be a little bigger.

[budm]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

DZ2W27000L has bigger footprint so you need to find way to fit into the old footprint.

[Shane711]

Re: LF501EM5F No Power, Chirping/Beeping Transformer

Would this be the correct part number for the 1 Watt Diode? DZ2W27000L