phillips lcd keeps blowing fuse

[TimT]

Re: phillips lcd keeps blowing fuse

2 diodes beep at both ends.. and 2 read about 5 to 6 and 0.. some go up to 19??? I have some 1n914 diodes they look about the same?

[TimT]

Re: phillips lcd keeps blowing fuse

all on board.. should i desolder one leg?

[Mr Bill]

Re: phillips lcd keeps blowing fuse

If it's the larger diodes there could be a part number printed on it. I would desolder one leg of the suspected diodes, lift it out of the board, and then recheck to make sure it is bad.

The "1" on your meter is infinity. SO a good diode with your meter would read .450 one way and "1" with the probes reversed. The .450 is just an example it could vary depending on if there are other components on that same trace.

[TimT]

Re: phillips lcd keeps blowing fuse

now im confused? " suspected diodes " very few have a "1" on one end most have a reading of 5.0 to 7.0 then reverse probes 7.0 to 8.0... would this be a suspected diode? ...
ok i just used a new diode " opened a new pack of 50 " and tested you are correct Mr Bill I got .667 then reverse probes got the 1 ..so looks like i still got a bunch of bad diodes..

[TimT]

Re: phillips lcd keeps blowing fuse

there is no " . " on my meter so its not 5.0 but. 500 not many diodes with 1 so about 90% are bad i would think?

[Mr Bill]

Re: phillips lcd keeps blowing fuse

If your getting a reading in both directions in circuit then it's going to have to be removed and rechecked out of circuit. I would say if 90% are really bad you are going to have way more time and $$ in the power supply than a working one off ebay would cost.

[TimT]

Re: phillips lcd keeps blowing fuse

I will remove one of them in the morning and post back. Thank you for your help!

[TimT]

Re: phillips lcd keeps blowing fuse

I tested a diode at .677 And .766 then removed the leg from the board. it test it out good! 1 on one side. could there be something on the board that would cause it to read incorrectly when mounted?

[ben7]

Re: phillips lcd keeps blowing fuse

I tested a diode at .677 And .766 then removed the leg from the board. it test it out good! 1 on one side. could there be something on the board that would cause it to read incorrectly when mounted?

Yes, thats why it is always good to take the diode off the board and double-check

[TimT]

Re: phillips lcd keeps blowing fuse

I would have to pull about 50 of them out lol... shouldn't they test good mounted? or at least most of them if they're in fact good

[TimT]

Re: phillips lcd keeps blowing fuse

ok, after testing many small diodes ( they all were good) i took a break and started testing some larger ones. 2 of the larger ones are " beeping " on both ends reading on meter is 0..pulled them off the board same thing.. the rest were ok. so I will order these.

I would like to test the bridge rectifiers. do i test these the same way? ignoring the middle pin? i guess there attached to the heat sink?

[Mr Bill]

Re: phillips lcd keeps blowing fuse

Here is a youtube video on testing the bridge. Your meter will need to be on the diode mode.

http://www.youtube.com/watch?v=dqkT6hF0O3E

[tom66]

Re: phillips lcd keeps blowing fuse

Those diodes are the bridge rectifier. It's marginally cheaper but less reliable to do it as four diodes.

[TimT]

Re: phillips lcd keeps blowing fuse

Thanks! I was looking for a chip with 4 pins " rectifier ".. none on the power board.. I will order the new diodes and go from there! how do i find the correct diodes? there marked LT 0342 IN5406 But this turns up nothing is a search..

[Mr Bill]

Re: phillips lcd keeps blowing fuse

That I is probably a 1 (1N5406)
http://www.digikey.com/product-detai...TPCT-ND/950583

[Mark369]

Re: phillips lcd keeps blowing fuse

here are the drawings for that board just check the number on the top corner of the board if it is BA01P0F0103 3. the same board that i have in my
emerson lc401em2f.

I have the full pdf ver. just to big to upload on here. that power suply look the same as the one im working on.

[Mark369]

Re: phillips lcd keeps blowing fuse

I found the link of the manual and the part number for you is on page 74.
http://www.scribd.com/doc/80791100/40PFL3705D-F7
have a good one.

[TimT]

Re: phillips lcd keeps blowing fuse

thanks everyone I'm just about to order the parts :-). I will report back when I get them installed

[Mark369]

Re: phillips lcd keeps blowing fuse

Thanks i hope you let us know

[TimT]

Re: phillips lcd keeps blowing fuse

after installing the new diodes. it's still blowing fuses any suggestions on what I should try next?