ilo V27DMBX dead totally

[CraigR]

ilo V27DMBX totally dead. no light on the front or anything. On the power supply I found 2 bad mosfets and the main cap was bad so replaced all those and the blown fuse. Same thing all dead. No caps are swollen and I replaced what I think was the start up cap and still totally dead. I have zero volts at all the pins on the connector. I know there must be an open someplace I think. I just can't find any info on this and there is no voltages printed on the board next to the plug so no clue what is to be there. The board is PN 6693006602

[CraigR]

Re: ilo V27DMBX dead totally

Another picture with the heat shield removed.

[CraigR]

Re: ilo V27DMBX dead totally

found another 22uF cap under that shield and replaced now also with same result. Plugged in on bench and only have 165V at the big cap.

[CraigR]

Re: ilo V27DMBX dead totally

I just pulled 7 of the ceramic caps (blue brown) and checked with my meter and those are ok also. I'm just lost on this one. Can anyone help?

[selldoor]

Re: ilo V27DMBX dead totally

Can you post a picture of the bottom of the Power board - which cap did you think was the start up. C26? Can you have only the power supply connected and check the connector that goes to the main board for 5v standby? Have you checked diodes and resistors for open?

[stj]

Re: ilo V27DMBX dead totally

it's possible the shorted fets damaged whatever was supplying the signal to the gate pins.

[CraigR]

Re: ilo V27DMBX dead totally

I replaced C15 and C26 I have zero volts on all the pins going to the main board Checked all diodes and resistors on top and are ok.

[selldoor]

Re: ilo V27DMBX dead totally

last pic is not really clear enough for troubleshooting - perhaps try in 2 halves
are the 4 black dots in a row the bridge rectifier? I usually try and find that to get my bearings

[CraigR]

Re: ilo V27DMBX dead totally

Not sure if this is any better. This is with my webcam. My regular camera wont focus that close.

[budm]

Re: ilo V27DMBX dead totally

So which two MOSFETs did you replace? The two next to each other are for driving the main transformer, the one by itself is for the PFC Voltage booster.

[CraigR]

Re: ilo V27DMBX dead totally

one is at Q20 on big heatsink and the other is Q17 on other heatsink that are next to each other. I also just checked the surface resistors on the bottom for an open and nothing.

[selldoor]

Re: ilo V27DMBX dead totally

Hi
Pics are a little better here is a sort of schematic


In with the group of secondary capacitors there is an inductor L2 can you test it for continuity.

[CraigR]

Re: ilo V27DMBX dead totally

L2 checks good!

[CraigR]

Re: ilo V27DMBX dead totally

On the underside there are 2 510k resistors connected together and put in some black shrink tube. I found that they were open so I ordered those and once I get those in I will report back.

[budm]

Re: ilo V27DMBX dead totally

Picture in post 2, it looks like one of the resistor (<1 Ohm) is for the Source pin and primary Ground (Negative leg of the main cap), and another resistor (in 1000'S of Ohms) is part of the snubber circuit.
Can you show the picture of the two resistors with the shrink tubing removed? Also the MOSFET for the PFC, when it shorted out it may have taken out the PFC IC also.

[CraigR]

Re: ilo V27DMBX dead totally

Here is the picture where the 2 resistors came off and I circled where they connected. I also have a pic of the resistors. I did go and check all the mosfets and they checked out ok.

[CraigR]

Re: ilo V27DMBX dead totally

Well I replaced those 2 resistors today and still got squat.

[budm]

Re: ilo V27DMBX dead totally

OK, those two 510K resistors are not the one I am asking about, they are these 3 resistors.

[CraigR]

Re: ilo V27DMBX dead totally

Here is a picture.

[CraigR]

Re: ilo V27DMBX dead totally

Ended up scraping it out.