Quick Resistor Question (Sharp LC-32D43U)

[saintlouis74]

I came across a Resistor that I can't identify, can anyone tell me the kind of resistor this is? and maybe a link to a replacement part... thanks



Markings:

6.8M Ohms
M1WJ

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

Is one leg of the resistor connected to the chassis and another leg connected to Neutral? This is a safety resistor with very high value and high breakdown voltage, it is not needed for the circuit to function. So what is the problem with the unit you are working on? Make and model?
BTW, those small blue caps are also safety cap (X/Y type).

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

Its a Sharp LC-32D43, with no power at all, i havent fully diagnose it, just popped the back off checked the fuse, then the resistor i questioned about had no reading, so i stopped to figure why it didnt

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

Post good clear pictures of the back side pf the TV and whole picture of this power supply board. There should be big main filter cap in the primary side of the circuit, it should have about 165~170VDC right at the two legs of the cap.
Was the TV hit by the surge or it just went out by itself?

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

thanks for the support

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

OK, so the fuse did not blow, right? You need o get access to those two brown caps laying on their side to measure the DC Voltages at the two legs of each caps, just be real careful since you are working in the Primary (deadly side) of the circuit.

[selldoor]

Re: Quick Resistor Question (Sharp LC-32D43U)

Hi Can you post a picture of the whole of the back of the tv.
and one of the other side of the power supply. Also as we cant see them for the wires close ups of the connectors showing the pin assigment 5v 12v gnd and so on.

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

I found good pictures provided by Shopjimmy, and the service manual.

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

Fuse was not blown, both the big caps read 168.9 VDC... and the picture budm posted are identical to my board..... Only thing i know about the TV is that it was working one day, and tried to turn it on the next and it wouldnt

[selldoor]

Re: Quick Resistor Question (Sharp LC-32D43U)

Ok - Can you try for a better picture of the back of your board if its still out.
Will help us spot bad joints.
If it is back together then testing secondary voltages on the connectors is next. Lodge the black probe of your meter on a ground screw then with the red probe test all the pins in the sockets. Set meter on 200vdc
List the results eg
GND ......gnd
5v......4.99v
on/off.... 3.2v and so on

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

sorry took so long to get back, but after probing all the pins got 0 Volt from every pin.. I did get 168vdc from the big caps, everything seems dead.. checked all the soldering joints they look good to me.

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

i dunno i missed it but i think i solved it, thanks to budm post

therdhttps://www.badcaps.net/forum/showthread.php?t=33077&highlight=Sharp+LC-32D42U

when part arrive i will post update on repair thanks

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

ok Diode was in bad shape, replaced that and found 2 resistor that was shorted out. i got them out and they are for sure blown... i just need guidance in finding a replacement part,

Markings:

F1J
FD774
0.12ohms

Location on Board:

R7933
R7626

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

OK, you have more problem. Those two resistors are Fusible resistors that will blow open circuit if the two power MOSFET Q7602, Q7603 are shorted out, you need to test and see if they have low resistance between S (Source) and D (Drain) pins, also the SMPS IC7603 may be also damaged. This is not good news for you.

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

OK, you have more problem. Those two resistors are Fusible resistors that will blow open circuit if the two power MOSFET Q7602, Q7603 are shorted out, you need to test and see if they have low resistance between S (Source) and D (Drain) pins, also the SMPS IC7603 may be also damaged. This is not good news for you.

MOSFET are goog from my knowledge,

i get 110 with red>source & black>drain
black>source & red>Drain i get 1
when i move Red>Gate then back to Drain i get a reading

As for IC7603 i followed :
https://www.badcaps.net/forum/showthread.php?t=27615

and i tested it and it seems ok also

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

Where can I order the Fusible Resistors from? link if possible thanks

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

That is strange to have two blown fusible resistors in the same circuit.
Digikey sells them but they are non-stock item.
http://www.digikey.com/product-searc...0&pageSize=500

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

That is strange to have two blown fusible resistors in the same circuit.
Digikey sells them but they are non-stock item.
http://www.digikey.com/product-searc...0&pageSize=500

how many Watts is it suppose to be?

[budm]

Re: Quick Resistor Question (Sharp LC-32D43U)

It looks to be around 1W, you will have to take the measurement on the body and look at the link I gave you for Digikey to see which one matches what you have. Or look at the attached PDF.

[saintlouis74]

Re: Quick Resistor Question (Sharp LC-32D43U)

It looks to be around 1W, you will have to take the measurement on the body and look at the link I gave you for Digikey to see which one matches what you have. Or look at the attached PDF.

ohhok thanks