Blown IC

Hi Group, need help identifying a blown IC. it's on Vizio e550-b2, power supply board # DPS-167DP ,.. Board locator # ic901, it has 7 pins, and the top is blown away.??

Reply to
Stu jaxon
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You missed an 'I'

Googling is remarkably effective with the right input.

e550I-b2 ic901

e.g.

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Apparently a LD7913JGM6, a PWM controller?

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Adrian C
Reply to
Adrian Caspersz

I have a .068 ohm resistor reading 0.00.. acting like a short, it is a low ohm resistor, is it supposed to read???

Reply to
Stu jaxon

board part # R804A...

Reply to
Stu jaxon

Reply to
ohger1s

wer supply board # DPS-167DP ,.. Board locator # ic901, it has 7 pins, and the top is blown away.??

w ohm resistor, is it supposed to read???

Did you zero the meter? Sometimes a low value resistor is shunted by a cho ke, and sometimes some residual voltage in the circuit will throw off a res istance reading. Try removing one lead of the resistor and checking again, and if it's OK, see if it is paralleled with another low resistance compon ent.

Reply to
ohger1s

power supply board # DPS-167DP ,.. Board locator # ic901, it has 7 pins, an d the top is blown away.??

low ohm resistor, is it supposed to read???

oke, and sometimes some residual voltage in the circuit will throw off a re sistance reading. Try removing one lead of the resistor and checking again, and if it's OK, see if it is paralleled with another low resistance compon ent.

I did lift a lead, and it's still reading zero, like a short.??? it doesn't look like it's paralleled with another low resistance component.

Reply to
Stu jaxon

w ohm resistor, is it supposed to read???

Lemme see. 0.068 ohms. Really? That would be within the margin-of-error for many cheap VOMs. Does your meter have a range-adjust? If you are in the 0-

10.000 range, you will not get a wiggle at 0.068 ohms. Of you are in the 0- 1 ohm range, that is entirely something else.

Peter Wieck Melrose Park, PA

Reply to
Peter W.

It would take a very special meter to show a .068 resistor value. That or measure the voltage across it with a known ammount of current through it.

For most meters there could be that much contact resistance.

Reply to
Ralph Mowery

0.068 ohms is basically a short. It's unlikely a resistor will fail shorted, so leave it alone, it's probably OK.
Reply to
Cydrome Leader

A 0.068 reading zero is not uncommon. Most ohmmeters do not measure that lo w. Suffice it to say it is not open, and it is very unlikely to short.

Before changing tht IC, you must find and fix any shorts on the secondary s ide of the transformer and identify the output pin. It will go straight to the transformers and may have either a cutout around it in the board or a c oating of white shit on the board.

Whichever it is, if nothing go with the ohmmeter from the top (+ probably) and find a pin that checks pretty much continuity to that gong to the trans former. Now look around, there will be a diode, resistor and a cap Make sur e those components are not open and as they are voltage snubbers without th em the IC is destroyed fast.

Reply to
jurb6006

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