Infocus power supply isssue

[subarub4]

I've been looking at this for hours but can't figure it out.. I have no power going to the projector, so I took the power supply out and I do have power coming in to it, but something is funny.. I have 120V in and about half way with the caps and all it seems the board is at 164VDC however the low voltage cable has no power to it, the plug for the ballast should have 390V but it has nothing.

Hopefully these pictures will help

[Khron]

Re: Infocus power supply isssue

"Just" 164V DC means the PFC definitely isn't working. That plug seems to be coming straight from that big reservoir/filter cap (that's at the output of the PFC) and normally, it should indeed be in the 380-390V DC area.

I'd say it's a safe bet that among that wire harness on the secondary (top right corner in the first photo), one of the wires is actually the PS_ON signal, which turns on the whole shebang.

Second "suspect" would be the two small electrolytics near the main PWM (lower right in the first photo). What brand / series are they?

[subarub4]

Re: Infocus power supply isssue

"Just" 164V DC means the PFC definitely isn't working. That plug seems to be coming straight from that big reservoir/filter cap (that's at the output of the PFC) and normally, it should indeed be in the 380-390V DC area.

I'd say it's a safe bet that among that wire harness on the secondary (top right corner in the first photo), one of the wires is actually the PS_ON signal, which turns on the whole shebang.

Second "suspect" would be the two small electrolytics near the main PWM (lower right in the first photo). What brand / series are they?

Hey thanks for responding, the wire harness goes to the main board which has the power switch however when plugged up and before I took everything apart when the projector is off the standby light should show (it does not) also pressing the power switch did nothing..

The two small electrolytic caps are Elite branded

C208 is 22 uF 50V
C204 is 47 uF 35V


The funny thing is the TO-220 which is a MR4010 for sure works, I used a IR temp gun and it gets up to around 122 F/ 50 C

Also at the lamp output I'm not getting anything.. at the black Cap which is 150 uF/450V I'm getting 164V at that but pretty much after that I have nothing.

The transformer on the far right says on the board O/P 5V/.15A| 12V/3.6A

[Khron]

Re: Infocus power supply isssue

The closest thing to a datasheet that i could find, is this:



Now, Elite is one of the "replace on sight" brands, for me

There's a small SOIC8 chip on the bottom of the board (that's the PFC controller) - what do the markings on it say?

[subarub4]

Re: Infocus power supply isssue

The closest thing to a datasheet that i could find, is this:



Now, Elite is one of the "replace on sight" brands, for me

There's a small SOIC8 chip on the bottom of the board (that's the PFC controller) - what do the markings on it say?

heh I saw that same data sheet and I had the "huh" feeling when I saw it.. and Elite haha another one... I guess any name is better then nothing as soon as I saw that I wanted to change out every one of them I saw.

SOIC8? Forgive me but where on the board is that?

[Khron]

Re: Infocus power supply isssue

SOIC8 = "Small Outline Integrated Circuit" with 8 pins/legs, and by that one i mean the small 8-legged chip on the back of the board, underneith the big heatsink, identified as IC101.

[subarub4]

Re: Infocus power supply isssue

SOIC8 = "Small Outline Integrated Circuit" with 8 pins/legs, and by that one i mean the small 8-legged chip on the back of the board, underneith the big heatsink, identified as IC101.

Oh ok I thought so..

Here it is

[Khron]

Re: Infocus power supply isssue

Found the datasheet for the (slightly more recent) A-version, R2A20113A.



Upon closer inspection of the photos, i reckon the voltage to that white 2-pin plug is actually turned on and off by the TO-220-packaged transistor right next to it (3-legged, no heatsink). Can't really make out where its control signal's coming from, though, but it might involve Q213.

Also, the PFC chip's Vcc supply line seems to be coming from the area around the main PWM chip; it's filtered by C117 and C117A (big ceramic caps right next to each other, on the bottom of the board). If you trace the circuit, you'll see that long PCB track ends up in the main PWM area - i can only keep track of it until near the small ceramic C118. Either way, you'll want to check if that's over 12v (PFC chip needs at least 12v to "wake up"; after that, it'll keep working until its supply drops under 9v).

[subarub4]

Re: Infocus power supply isssue

Found the datasheet for the (slightly more recent) A-version, R2A20113A.



Upon closer inspection of the photos, i reckon the voltage to that white 2-pin plug is actually turned on and off by the TO-220-packaged transistor right next to it (3-legged, no heatsink). Can't really make out where its control signal's coming from, though, but it might involve Q213.

Also, the PFC chip's Vcc supply line seems to be coming from the area around the main PWM chip; it's filtered by C117 and C117A (big ceramic caps right next to each other, on the bottom of the board). If you trace the circuit, you'll see that long PCB track ends up in the main PWM area - i can only keep track of it until near the small ceramic C118. Either way, you'll want to check if that's over 12v (PFC chip needs at least 12v to "wake up"; after that, it'll keep working until its supply drops under 9v).

The 3 legged TO-220 near the white plug is P1260ATF As for the PFC chip I'm not seeing voltage on it at all

[subarub4]

Re: Infocus power supply isssue

I hope this helps I made lines to show where the TO-220 goes to.

[Khron]

Re: Infocus power supply isssue

Hmmmmm... Judging by how Q204 and Q213 are arranged, i'm starting to get a hunch that maybe that FET is actually triggered by a signal from the secondary, through the left-most optocoupler (in this last photo)...

Do you have access to a multimeter (ideally one with a continuity-tester, aka "beeper")? It could help a lot in tracing this circuit, what with traces going under surface-mounted parts and all...

[subarub4]

Re: Infocus power supply isssue

Yep I have one of those meters

[Khron]

Re: Infocus power supply isssue

Any chance you could try to lift the schematic of that piece of circuit, then?

[subarub4]

Re: Infocus power supply isssue

I can try..

Q213 when I touch the two pins closest to each other I get continuity on the other hand for Q204 I get nothing

[subarub4]

Re: Infocus power supply isssue

Q602 and the trace that runs down to C118 & R129 are connected which seem to go to Q204 & Q213 which ends up at those optoisolators.

Right now I'm temped to replace all the caps with Panasonic's but still curious where in the circuit the voltage just drops out at.

[Khron]

Re: Infocus power supply isssue

What are the markings on Q204 and Q213?

[kc8adu]

Re: Infocus power supply isssue

looks like that shrinkwrapped cap near the transformer is bulged.
i would replace all.
and i suspect that once the 5v is there again a power on command from the logic will fire up the pfc and the unit will work.no pfc in standby.very common.

[subarub4]

Re: Infocus power supply isssue

what are the markings on q204 and q213?

q204 =241
q213 = 241

[subarub4]

Re: Infocus power supply isssue

looks like that shrinkwrapped cap near the transformer is bulged.
i would replace all.
and i suspect that once the 5v is there again a power on command from the logic will fire up the pfc and the unit will work.no pfc in standby.very common.

I wanted to know why are these shrinked wrapped in the first place? I took the shrinkwrap off and it's not bulging it's 220 uF 16V and one of the few caps I do have around that matches but only 85C rated but OK just to test.

I wont do that much more until all the caps are replaced and hopefully I will get that order placed today. Only comes to like $7 in all.

[subarub4]

Re: Infocus power supply isssue

I'm probing around here checking some diodes and I found one here D106A in diode test it reads 0V both ways.. on the backside of it is a white 0.025 Ceramic resistor.