Benq W1070 projector smps

[tibimakai]

Re: Benq W1070 projector smps

I believe that is what is going on here, something is bad on the mainboard.
The question is, why both voltages are fluctuating? Must be something common.
With everything disconnected from the mainboard, still fluctuates. That means that not the fans, or the color wheel/motor are causing this.
Maybe the PMD1000 IC?

[R_J]

Re: Benq W1070 projector smps

If the 3.3 volt drops, the it will effect the standby power supply feed back, so the 12 volts will also be changing, If you look at page 8, try and locate U96 and measure the voltage on it. If the input (1,2,3) are jumping, measure the voltage on (5,6,7,8). If it is 0 volts, then the likely cause is a load on the 3.3 line

[tibimakai]

Re: Benq W1070 projector smps

Sounds good. Most likely, I will do it on Wednesday.
Since I'm not repairing TVs anymore, I need to buy one, if I need one.
Tomorrow, arrives a refurb. Samsung UN55MU6290($357 shipped, from Walmart).
Tomorrow, I will be busy with that.

[R_J]

Re: Benq W1070 projector smps

These schematics are a pain in the ass to follow, it looks like the 3.3v from the standby is the P3P3V_LP, (page 8) so what ever it supplies after that could be loading it. but don't confuse it with the A3P3V_AFE, they are different.

[tibimakai]

Re: Benq W1070 projector smps

OK, sounds good. Thank you for all your help. It is much appreciated.

[tibimakai]

Re: Benq W1070 projector smps

Ok, I have measured both voltages, and both are jumping.
With min/max, at pin #1/2/3 I'm getting 4.7V and at pin #5/6/7/8, 1.37V.
Still measuring with min/max, at TP 178= 1.43V, TP 177= 0.18V.

[tibimakai]

Re: Benq W1070 projector smps

So, it seems like I have a short on the 12V rail.
After the U96, I measure 1.63 Ohm.
All the U110/U111/U112 etc., at pin #2, which is the 12V supply, I measure 1.63 Ohm.
I have tried supplying external power to it, but consumption is 0A. Nothing heats up.
What I'm doing wrong?
Placed 12V power supply, at pin #3 at CN701 and negative, to pin #7.
OK, I have placed the positive lead after the U96 and my power supply jumped to the max. 5A and I have used low voltage to do this test. At this point, I have found U42(PMD1000) IC, was getting hot.
I have measured other outputs from this IC, and they are not shorted to the ground.
So at this point, I have to assume, that this IC is shorted, right?
Before I remove it, I would appreciate your input.

[tibimakai]

Re: Benq W1070 projector smps

It seems like, it wasn't the shorted part.
After removing it, I still had a short. Smaller, it was 1.35 Ohm.
I have found a capacitor under(other side of the board) this IC, that had a chipped side.
After removing it, the short has lifted.
The problem that I'm facing is, that there is no value on the schematic. It just shows CAP_NP. These seem like de-coupling capacitors, they are all over the board.
What should I use in it's place?

[R_J]

Re: Benq W1070 projector smps

I don't know for sure, If you could check the value of one that looks the same that would give you a value, if not it is likely a 0.1 or maybe 0.01
It is likely the projector will work without it

[CapLeaker]

Re: Benq W1070 projector smps

maybe upload a pic of the affected area.

[tibimakai]

Re: Benq W1070 projector smps

I have found one that size wise is the same and the value seems very close.
I have soldered it in and the Power button's LED turn solid green and the Power LED shows red. It looks like, it is in download mode.
Nothing turns on, none of the fans or lamp. I will need to measure some voltages.
I don't know, how to get out of this mode.

[tibimakai]

Re: Benq W1070 projector smps

I'm also reading in the Level 2 SM, that red light could also mean, that is not ready for standby.
https://www.scribd.com/doc/208363905...Service-Manual

[tibimakai]

Re: Benq W1070 projector smps

I have stable voltages, at CN701: 3.3V= 3.23V, 12V= 14.7 pin #2= 3.1V.

[tibimakai]

Re: Benq W1070 projector smps

It is hard(impossible) to measure anything under the board. Test point numbering, does not match with the schematic, only some of them.
I have only one power supply, so I can't supply both voltages, with the board removed. I will have to come up, with some kind of power supply.

[R_J]

Re: Benq W1070 projector smps

Are you getting the 380 volt on CN603 now? I also see CN702 where the thermal wire is connected? Is the thermal device ok, it likely should check low resistance. looks like it is needed to get the 12 volts to the ic653 opto to turn on the 380 supply

[tibimakai]

Re: Benq W1070 projector smps

No, I'm not getting 380V, yet. Most likely, it is not turned on, by the mainboard.
The thermal wire, is connected and is shows 0 Ohm.
At the opto IC653, I'm getting 12.6V, at one of the pins and on the other, is 12V.
I have a feeling, that there is still something wrong, on the mainboard.
Somehow, I will have to check for all the voltages, if they are OK or not.

[R_J]

Re: Benq W1070 projector smps

Looks like PFC_ON is still needed to turn it on. That signal comes from U104 Power Control MCU (page8)

Which capacitor was shorted that was causing U42 to get hot? maybe that could be a clue to what is else is wrong?

[tibimakai]

Re: Benq W1070 projector smps

Today I'm done, but hopefully tomorrow, I will take out the mainboard and I will apply 12V, and start checking the voltages on PMD1000 IC, there are a couple of voltages.

[tibimakai]

Re: Benq W1070 projector smps

It was C297. Right under U42(PMD1000).

[tibimakai]

Re: Benq W1070 projector smps

I'm trying to measure some voltages, but unfortunately, I can't reach to the bottom of the board, where are most of the measuring points are located.
I have 14.7V, at both ends of U96. I have also 14.7V at the C297 that I have replaced. This feeds U42 IC. I can't reach, at the outputs of U42.