Samsung LN32A450C1D Red light

[tom66]

Re: Samsung LN32A450C1D Red light

Voltages are OK (pin 9 is connected to Vcc making start threshold 9~11V.) So, either the IC is bad or something is being mis-detected and firing one of the FAULT inputs (the over-volt detect is probably not the cause as the outputs never rise.)

Can you get a photo of this ICM801 - is it easily accessible for testing?

[CraigR]

Re: Samsung LN32A450C1D Red light

That must be it. Out of circuit it reads nothing, must be open.

[CraigR]

Re: Samsung LN32A450C1D Red light

Icm801

[budm]

Re: Samsung LN32A450C1D Red light

"That must be it. Out of circuit it reads nothing, must be open." The cap?

[CraigR]

Re: Samsung LN32A450C1D Red light

Yes the cap, now where to get one.

[tom66]

Re: Samsung LN32A450C1D Red light

ICM801 please check the following pins with the negative lead of your multimeter on the negative of the 450V capacitor. Careful high voltage present across primary side.
- pin 5, Vref, 5~5.2V
- pin 9, enable, >2V
- pin 11, soft start, >2V

CM808 must check on capacitance range, will check open on most resistance checks.

[budm]

Re: Samsung LN32A450C1D Red light

It does not show capacitance of .018uF (18nF) on the cap meter?

Polypropylene metalized, High Frequency, Switching.
This is what I use: .018uF 630V
http://www.digikey.com/product-detai...2122-ND/585189

[CraigR]

Re: Samsung LN32A450C1D Red light

tom I think this blue square cap CM808 is bad as it has no readings.

[tom66]

Re: Samsung LN32A450C1D Red light

A good capacitor will give "no readings" on ohms. You must check this capacitor on capacitance range, if your meter has that feature. If it does not, check voltages as I indicate, if they come back good IC is probably working so capacitor is probably bad.

[CraigR]

Re: Samsung LN32A450C1D Red light

Right 0.0uF

[budm]

Re: Samsung LN32A450C1D Red light

I replaced many of this cap in Samsung power supply board, probably bad batch, the newer boards use the same body/type as I have on Digikey. When I see this cap in style cap in Samsung power supply board, I replace them needed or not, it is used in Samsung monitor power supply boards also.

[CraigR]

Re: Samsung LN32A450C1D Red light

Well I just ordered it. IF you guys feel like subcribing to this thread I will re-post once I get i get it in. And a big thank you guys! Your help is greatly appreciated!

[CraigR]

Re: Samsung LN32A450C1D Red light

Darn! that did not do anything. Not sure what the deal is with my meter either. It's a month old Milwaukee MM and I tested the new cap before I put it in and it also read 0.0 but yet I took a round cap and it reads it just fine. I had it on Autorange so I would think that would work. Looking at a Fluke 115 MM now. Anyway what next??

[CraigR]

Re: Samsung LN32A450C1D Red light

ICM801 please check the following pins with the negative lead of your multimeter on the negative of the 450V capacitor. Careful high voltage present across primary side.
- pin 5, Vref, 5~5.2V
- pin 9, enable, >2V
- pin 11, soft start, >2V

CM808 must check on capacitance range, will check open on most resistance checks.

Assuming I have the right pins pin 5=5.07v then drops to 2mV then back up.
pin 9=14.73 and pin 11=jumps all over in mV range have a look at this picture this is how I figured the pins.

[CraigR]

Re: Samsung LN32A450C1D Red light

I also pulled every cap off the board now and check with ESR70 and all are good. Less than 10% off.

[vlado64]

Re: Samsung LN32A450C1D Red light

The blobs of glue holding the components in place become conductive after a while resulting in a short between the parallel wire links feeding the mains smoothing capacitor and CM810 (2.2nF/1KV) , Q802

[CraigR]

Re: Samsung LN32A450C1D Red light

Ok, just tried cleaning all the glue from everything but same results.

[tom66]

Re: Samsung LN32A450C1D Red light

ICM801 please check the following pins with the negative lead of your multimeter on the negative of the 450V capacitor. Careful high voltage present across primary side.
- pin 5, Vref, 5~5.2V
- pin 9, enable, >2V
- pin 11, soft start, >2V

Please check these voltages as indicated previously.

[CraigR]

Re: Samsung LN32A450C1D Red light

I did as stated a couple posts up.

[tom66]

Re: Samsung LN32A450C1D Red light

Whoops, did not notice that. Now Vref should not drop out. Neither should softstart. It could be bad IC or something shutting down IC. Check pin 15, Vcc. Should be a stable voltage, about 15V.
Softstart might be being pulled down by the circuit which detects PFC voltage being low (QM805, etc.)