Xerox 17" LCD problem - caps?

[tiggerific]

Received a Xerox XL370s (ProView re-brand) 17" LCD which had power-up problems. No display on power, the power led flashes and a clicking sound is audible. Opened it up to check the boards but they looked fine. Disconnected the panel and it powers right up, backlights operational. If I re-attach the panel it just sits there flashing the led & clicking. Caps on the display board are Su'scon brand, none appear to have leaked / bulged and they are all 220@16 or 100@16. There is heat discolouration around the 3.3V regulator section and on the bottom of the board so is it possible that the capacitors in that area (5 are close, 3 would get most of the heat flowing around them) are dried up & causing the problem?

All fuses are good on all the boards including the panel. Cable continuity is also good.

I also checked the power supply in case it wasn't putting out enough juice but it appears to be good (proper voltage), all the caps look good, United Chemicon series LXZ.

Any ideas?

Thanks,
Alex

PS: sorry for the pic resolutions, I'm using my PDA camera

[zandrax]

Re: Xerox 17" LCD problem - caps?

Welcome tiggerific.

Su'scon was a bad brand in past and your caps are suspicious even if capacitances are small (100-200 uF), but the troublesome part may even be an inverter or another chip on the inverter board.
I'm not an expert so I'd suggest taking a better quality photo of the inverter board and waiting for KC8 or Davmax replies.

Zandrax

[tiggerific]

Re: Xerox 17" LCD problem - caps?

Thanks Zandrax, however the inverter board works fine - it's a seperate pcb I didn't take a picture of just because it works The power LED flashes if the panel is plugged into it, and there is no backlight. Without the panel the LED turns on solid green and then goes into standby, also the backlights turn on and then they also go into standby. Without the inverter board attached I get the same response from the LED.

Cheers,
Alex

[tiggerific]

Re: Xerox 17" LCD problem - caps?

As a bit of a follow-up I found one 100uF capacitor which looked dodgy, near the crystal in the 1st picture. Almost looks like someone did a bit of a "repair" in the past to a smd resistor and melted the side of the can. Anyways, I tacked a 100uF cap onto the back I had extra from recapping some other LCDs and voila the LCD turned on yay.

Crap picture, all white with a couple vertical lines which faded in and out and the text vanished almost instantly but it did work.

My question now is: does anyone know where I can get low profile (5mm) 220uF and 100uF 16v caps? All the low ESR ones I've been finding googling are too tall...

Cheers,
Alex

[zandrax]

Re: Xerox 17" LCD problem - caps?

Try contacting member BigPope: he sells Samxon capacitors and may be able to get hard-to-find caps directly from the factory.
Other sources can be found in this post.

Zandrax

[sky]

Re: Xerox 17" LCD problem - caps?

Hi,
So i have one of these monitors and it is acting a bit odd. Heres what happens...

When i turn it on, it will come on for about a second then the screen will go black and the backlights turn off.

Heres what i have done so far.
When i first got it one of the backlights was red/going bad so i replaced that.
(No change in behavior other than the image is now clear for the sec. its on)
Next, i found badcaps.net and figured that i might have the same problem as the above post, i ordered some new caps from mouser.com and replaced all of the caps on the main controller board (only one i didnt replace was the 22uf 30v?? as i forgot to order a replacement for it).
At this point there is still no change.

The only time i can get the monitor to come on is if it is off and i turn on the power. Or if it is in "sleep" mode and i hit one of the buttons like Menu or Auto. It doesn't make a difference what i do, it will still only stay on for a second.

I have concluded that there is possibly a bad chip or something of the sort on the mainboard. I have a "repair manual" i found on the net for a proview (that supposedly is what this monitor really is). I have done everything it suggested and then some.. Im hitting a brick wall at this point because i cant even find a replacement part for the controller board.

If anyone here can give me some pointers i would be very happy. Also, i can provide a link to the "repair manual" as well as some "high-res" images of the controller board (or even the inverter if needed).

Thanks,
-Sky

[EGuevarae]

Re: Xerox 17" LCD problem - caps?

I have a Proview 568 (15") with the same problem as the one in this thread, and replaced all caps with Jamicon and nichicon (tall, but just to test) and it works OK. Now I can't find 5mm low profile caps. Any idea?

[PCBONEZ]

Re: Xerox 17" LCD problem - caps?

https://www.badcaps.net/forum/showpo...8&postcount=17