Re: Dell E173FPf with Su'scon caps
Alright, replaced U850, but now I have fluctuating voltage across C857 (equal to pins 1 and 7 on the SMPS) between 12.1V and 15.8V, with no power to other pins at all, other than pin 3 at 18V but fluctuating slightly. Replaced cap C857 again with no change.
yotefn
Member
Last Activity: 05-16-2012, 05:01 PM
Joined: 03-15-2012
Location: Providence RI
-
Re: Dell E173FPf with Su'scon caps
Recapped C857, no change.
Analyzing the datasheet and looking at the voltages on U850 at pins 7 and 8, I checked continuity with the IC on the board of those two pins and they were shorted. So I removed the IC and checked again and they're shorted. Ordered a new IC on ebay from Hong Kong (no one reputable carries the chip anymore), will replace and report.
Thanks for your help.Leave a comment:
-
Re: Dell E173FPf with Su'scon caps
OK, that's good to know.
Here's a list of measurements:
Across primary and secondary windings of transformer is non-infinate resistance so I guess thats good for now considering all the other bad measurements.
Using filter cap as ground:
to cold ground: 67VDC
I850 Pins 1 and 2, U801, U802 U851: 67VDC (all pins of these same as cold ground)
I850 Pins 3,4: 0V
U850
Pin 1,2,4,6: 0VDC
Pin 3: 4.4
Pin 5: 0.1 (consistently bumped meter slightly)...Last edited by yotefn; 04-29-2012, 08:20 AM.Leave a comment:
-
Re: Dell E173FPf with Su'scon caps
Woa! After seeing this page and billy66's post:
[url]https://www.badcaps.net/forum/showthread.php?t=11330&highlight=u850&page=2[/url]
I measured my U850, which I assume is the PWM chip. Other than pin 1, I think every pin measured -68.7VDC (negative), except for one pin which measured positive same voltage.
The center pin on Q850 was also -68.7VDC
Now I'm no electronics geek, but after rectification why would I be measuring negative voltage? If the whole thing is shorted...Last edited by yotefn; 04-28-2012, 09:35 PM.Leave a comment:
-
Dell E173FPf with Su'scon caps
Hi, monitor has no power at all, no LED at power button.
Attached are pictures of the board, the video and power are on the same board.
Probing with a meter, I get 169VDC at the big filter cap, and at the primary connections at T850. I do not measure any other voltages anywhere else on the board, including any direction on the secondary of the transformer. My guess at this point would be the transformer is shot. It's marked "SPW-039 TDK X 0434". I have no idea what the output power or current would be.
2 Questions:
1)Does anyone have any ideas what... -
Re: Backlight wont come on at all
There are only 3 on the board. It has an external power brick to bring it down to 12VDC at input....Leave a comment:
-
Re: Backlight wont come on at all
It would seem to me that the blown caps were the reason, bad caps will draw more power. It's easy to test, though.
I've never seen anyone mention newark.com or mcmelectronics.com on this site, they also carry a great stock but shipping is a killer when you don't make a large order.
It would be nice if there were still local electronics supply houses around, but they've seemed to have gone extinct.
Thanks again....Leave a comment:
-
Re: Backlight wont come on at all
Yup, fuse was blown... I soldered a jumper wire to test and the monitor comes on now. Where can I get a replacement fuse for this?...Leave a comment:
-
Backlight wont come on at all
Hi, I have a Staples 19" sp9106 LCD. Backlights went out completely, but LCD still shows a picture (while very hard to see.) Power light is steady. Recapped 3 blown CapXon KF with Panasonic FM's with same rating. This didn't help at all...
There is no visual indication on either the power or logic boards of any problem. The only thing I can guess with totally dead lights is a blown fuse but I don't see one.
This thread already discusses this monitor and has pictures of the boards:
[url]https://www.badcaps.net/forum/showthread.php?t=12284[/url]...
No activity results to display
Leave a comment: