Dell E193FPc

[Peale]

Received this monitor from someone who was just going to toss it.

He stated that he had capped it, and that it had not worked after that, so he tossed it into a corner.

When I opened it up, it was obvious what was wrong: the mosfets were blown open. Charred. Replaced them, and then it worked! Well, the backlight works. It has a white picture, with pinkish lines on the sides.

I'm really hoping to get this going again, since it's a 19" 4:3 monitor. Great for arcade games.

Photos, forthcoming.

[Peale]

Re: Dell E193FPc

And, here are the photos.

Something tells me that this is either the logic board, or a poor connection to the LCD panel.

[budm]

Re: Dell E193FPc

It sounds like the T-con on the LCD panel assembly may not be getting either 5 or 12V from the logic board, check the fuse and the voltage on the LCD panel.
See examples:
http://s807.photobucket.com/albums/y...cpZZ2QQtppZZ20

[Peale]

Re: Dell E193FPc

Curses...I don't have a small enough Phillips screwdriver handy. I'll check it ASAP.

[jetadm123]

Re: Dell E193FPc

Transistor Q210 on the power board between the two inverter transformers looks like it shorted out.

Disregard, I see that you already replaced them.

[Peale]

Re: Dell E193FPc

Transistor Q210 on the power board between the two inverter transformers looks like it shorted out.

Disregard, I see that you already replaced them.

Yup! Although I'm curious how you noted that - the board isn't browned or blackened there, that I can see.

edit: never mind - it's quite obvious, in the photo.

[Peale]

Re: Dell E193FPc

It sounds like the T-con on the LCD panel assembly may not be getting either 5 or 12V from the logic board, check the fuse and the voltage on the LCD panel.
See examples:
http://s807.photobucket.com/albums/y...cpZZ2QQtppZZ20

Finally found the right size screwdriver. There's only one fuse, and it appears to be fine (verified with mulitmeter). From where do I verify voltages?

[budm]

Re: Dell E193FPc

Black probe on the chassis, red probe on one end of the fuse at a time.

[Peale]

Re: Dell E193FPc

Black probe on the chassis, red probe on one end of the fuse at a time.

2.86 VDC, either side of the fuse.

[jetadm123]

Re: Dell E193FPc

2.86 VDC, either side of the fuse.

Voltage seems a bit low. Typically, it's more like 5 VDC. Try measuring for the 2.86 V at the black wiring harness of the main board and trace your way backwards.

[Peale]

Re: Dell E193FPc

Difficult to trace back. A schematic would be helpful. The board is dual layer, so moving it around, while on, hasn't been easy.

Knowing what the voltages are supposed to be on the input/output pins would be helpful. On the harness from the PS to the logic board I found 3.03V, but I'm not sure if that's feeding that.

[budm]

Re: Dell E193FPc

Diagram of the main board if it matches yours. I expect 5V as well. There is a switched transistor that supply the voltage to the T-CON.

[Peale]

Re: Dell E193FPc

Diagram of the main board if it matches yours. I expect 5V as well. There is a switched transistor that supply the voltage to the T-CON.

I'm having trouble trying to follow that. On page 27 I can find the connector (CN103) but I don't see the transistor you mention on that schematic.

As a guess, when looking at the board, itself, there's U105.

edit: found U105 on page 28, but it just has traces going to nowhere. I can see that it outputs both 3.3 and 5...

I'll power it up and see what it puts out. When I use the diode function of my meter to test it, it reads every which way. Perhaps it's because it's in circuit...or, perhaps it's bad.

[budm]

Re: Dell E193FPc

Please see PDF.

[Peale]

Re: Dell E193FPc

Found them both. Testing them in circuit also gives some odd results.

They're really small, and in a bad spot. I don't have the equipment to replace them properly.

[Peale]

Re: Dell E193FPc

Tested the voltages coming off of Q104, here are my results.

I don't know which pin relates to B/C/E, so I included this photo to illustrate what I'm looking at.

Top pin - 5.06V.
Left pin - 0.08V
Right pin - 5.06V.

Does that mean that the 5V is being interrupted somewhere upline?

[budm]

Re: Dell E193FPc

It is MOSFET which has S, D, and G.
S should have 5VDC, G = ~5VDC, D (the top tab) = 5vdc
Also take the resistance reading between the D and the fuse on the T-CON board to make sure that it is less than 1 OHM.
Voltage measurement must be done with the monitor power on and with running PC.

[Peale]

Re: Dell E193FPc

Do I need to have a running PC if this is one of those monitor which is "always on" when it's on?

[Peale]

Re: Dell E193FPc

So...

Source = 5.06V
Gate = .08V
Drain = 5.06V

That's without the LCD panel attached. Working on that, now...

[Peale]

Re: Dell E193FPc

Also take the resistance reading between the D and the fuse on the T-CON board to make sure that it is less than 1 OHM.

It's reading in the MEGA Ohms. Red lead to Drain, black lead on the fuse on the TCON. So, somewhere, I've got a break, correct?