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Crumbtrail TV Forums: TV Equipment: TV Repair Forum:
What value zener diode? LF501EM4

 

 


Pyper
New User

Dec 6, 2017, 11:20 PM

Post #1 of 6 (144 views)
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What value zener diode? LF501EM4 Can't Post

I have an Emerson 50" TV model number LF501EM4.
The power supply (BA3AU0F01023) was making a chirping sound.
I traced it down to zener diode D1707.
The diode I pulled out has the label 1N4735A 408Y.
But from what schematics I found online it says the D1707 should be 1ZB36BB.
Which should it be? does it matter?



jts1957
Veteran


Dec 7, 2017, 6:37 AM

Post #2 of 6 (135 views)
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Re: [Pyper] What value zener diode? LF501EM4 [In reply to] Can't Post

Assuming one you pulled out is 'The Original,' then 6.2 volts 1 watt it is.


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Location: Far, Far Away


Pyper
New User

Dec 7, 2017, 3:37 PM

Post #3 of 6 (130 views)
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Re: [jts1957] What value zener diode? LF501EM4 [In reply to] Can't Post

Thanks!
I guess it will either work or it won't.
Will try the 1N4735A
Would like to get this working, someone just threw it away so to fix it for the cost of a zener diode would be great!


jts1957
Veteran


Dec 7, 2017, 8:56 PM

Post #4 of 6 (118 views)
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Re: [Pyper] What value zener diode? LF501EM4 [In reply to] Can't Post

A .15 ohm resistor is in parallel. Let's hope was testing BAD out of circuit.


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Location: Far, Far Away


Pyper
New User

Dec 14, 2017, 9:10 PM

Post #5 of 6 (77 views)
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Re: [jts1957] What value zener diode? LF501EM4 [In reply to] Can't Post

well, that didn't work.
something is still chirping.
how can I figure out what is chirping?


jts1957
Veteran


Dec 14, 2017, 9:55 PM

Post #6 of 6 (76 views)
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Re: [Pyper] What value zener diode? LF501EM4 [In reply to] Can't Post

I'd remove the board and check (in circuit on Diode test of meter). Any that read suspiciously, float either end and retest (out of circuit). There can be more than just the one you found. Also test semiconductors that connected to bad diode.


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Location: Far, Far Away

 
 
 


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