Westinghouse WD40FW2490 not powering up

[R_J]

Re: Westinghouse WD40FW2490 not powering up

.8 drain to source is is not good but it may not be the component that is shorted. Yes, center pin is connected to tab. Have you checked the large diode to the right of Q2054, also check the resistance across that large cap next to the diode. You could lift the source pin of that Q2054 but sometimes you can damage the transistor. so check the other parts first

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

OK, in circuit, the big diode measures about 2.8 ohms in both directions. The same with the Cap. I pulled the diode (marked "HER304") and it still measures the same out of the circuit. The cap now measures more like a cap should, with the resistance changing as it charges/discharges.

[R_J]

Re: Westinghouse WD40FW2490 not powering up

Looks like you found the problem, you can replace it with one thats a bit better like a HER306, HER307 or HER308

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

One more step down the road...

I replaced the HER304 diode with an HER308 and was still getting a short across it. I was able to lift the source leg of Q2054, which is an MDD14N25, and the short across the diode went away. With the source leg lifted, Q2054 was still a short between source and drain (the big tab), so I figured I might as well go ahead and order it. It finally arrived today (from the UK), and I installed it.

I now get a Red light on the front panel once I plug it in, and hitting the power button gets me a Blue light. I now get 4.9V on the connector with the 5 volt pin and 11.9 on the connector with the 2 x 12 V pins, so Im making progress.
I also can see that the led in the Toslink connector is also on.

I'm still not seeing anything on the display when I try the menu or source buttons.

What's my next step?

Thanks
John

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

A quick little update.. I tried the "flashlight test" and I am able to see the Westinghouse W logo when it powers on and the Scanning channels menu, so it appears to be a backlight issue.

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

Does anyone have any suggestions on the next steps in troubleshooting this issue?

[dick_barton]

Re: Westinghouse WD40FW2490 not powering up

So what voltage do you have on the red and white lead going off to the backlights in standby and when you come out of standby?

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

I finally got back around to looking at this again.

The red and white wires on the black sleeved connector (in post #3), which I believe is the connector going to the backlight measure as follows to chassis ground:

Standby
Red ~ 2 V DC and slowly draining
White ~ 30 V DC (with several that were 40V ish..)

On
Red 12V DC
White 1.5V DC

Any suggestions would be appreciated.

[nomoresonys]

Re: Westinghouse WD40FW2490 not powering up

Whats the voltage across the filter cap when powered on?

[budm]

Re: Westinghouse WD40FW2490 not powering up

There is a lytic cap (KF printed on it) laying on its is side close to the LED connector, put meter probes on each leg of the cap to check the Voltage when TV is off and when TV is turned on, you must keep an eye on the meter to see how high the Voltage jumps up to when TV is turned on and then wait 10 seconds to see how low it goes down to.

[Mr_Slim]

Re: Westinghouse WD40FW2490 not powering up

Ok.. got a little egg on my face.. after doing the measurements, I was putting the back cover on again, and I noticed a connector that was hanging loose, coming out of the back of the LCD display.. The backlight came on after turning it on this time, and I can get into the menu. I'll need to find a replacement remote, but I think I'm good.

Thanks everyone for your help!

[nomoresonys]

Re: Westinghouse WD40FW2490 not powering up

Ok.. got a little egg on my face.. after doing the measurements, I was putting the back cover on again, and I noticed a connector that was hanging loose, coming out of the back of the LCD display.. The backlight came on after turning it on this time, and I can get into the menu. I'll need to find a replacement remote, but I think I'm good.

Thanks everyone for your help!

Lol, I think we've all done that, more than once, good to hear its fixed.

[captainKKK]

Re: Westinghouse WD40FW2490 not powering up

I have same curbside special model, board model ST6308RTU-AP1. Turning on only displays the Element logo. Do not have remote. Only the power button on the panel turns it on but not off. All inputs not tested, because cannot switch inputs using the panel buttons. Have plugged active VGA and HDMI with no change. Large cap 172 vdc before pushing power button. Large cap 165 after pushing power button on panel. Only normal ELEMENT logo shown with full back lights. CN2054 shows 12vdc and CN2055 has 5vdc. D2012 has 12.3 vdc between both legs and chassis when powered on, temp is 105F. Main aluminum heat sink has 98F. Any ideas?

[captainKKK]

Re: Westinghouse WD40FW2490 not powering up

Example, see pic

[captainKKK]

Re: Westinghouse WD40FW2490 not powering up

https://www.eserviceinfo.com/

[dick_barton]

Re: Westinghouse WD40FW2490 not powering up

You have a few voltage regulators on the mainboard you could check. What is the number on the top of the 8 pin iC near to U6? Possible EEPROM reading issue.