Re: Samsung UN32EH4003F
Ok, The backlight does not come on with the mainboard disconnected and power is applied. I see 13V on B13 and 5.3 on B5 as per the board test points. Not sure where else to test for the standby voltages.
Mr_Slim
Member
Last Activity: 12-24-2023, 08:04 AM
Joined: 06-03-2018
Location: Ottawa, Ontario
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Re: Samsung UN32EH4003F
Ok, I see 13.8 V on B13 and 5.3V on B5V, so I expect those are the standby voltages.
When I measure the voltages on the CNL802 connector (the backlight power connector I suspect), (to ground) with the backlight disconnected
1 (D+) = 131.5V DC
2 (S-) = ~1.8V (and it seemed like it was discharging)
4 (S+) = (same as S-)
5 (D-) = 2V
with the backlight connected:
1 (D+) = 130V
2 (S-) = 16.25V
4 (S+) = 16.25V
5 (D-) = 2.2VLeave a comment:
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Re: Samsung UN32EH4003F
Thanks, Are you saying that the backlight should come on even though the power switch, (which is controlled by the mainboard) is disconnected?
Also, where do I check the standby voltage on the power supply?Leave a comment:
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Samsung UN32EH4003F
Hi All,
This TV appears to have a backlight failure. Suggestions where to start are appreciated.... -
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!Last edited by Mr_Slim; 12-15-2018, 02:31 PM.Leave a comment:
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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.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
Does anyone have any suggestions on the next steps in troubleshooting this issue?Leave a comment:
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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.Leave a comment:
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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...Leave a comment:
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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.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
OK, so the right pin (source) to the tab is .8 ohms. and the left pin (gate) to the tab is 384 ohms. (both directions). I presume the Drain (middle pin) is tied to the Tab?Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
So, cathode to ground on both diodes shows about 1.5 ohms, while Anode to ground is .1 ohm, which is the same as the resistance of the meter leads, so effectively a short..Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
After pulling the snubber cap, the resistance across the diode pads is about 1.7 ohms.
The cap itself seems to charge/discharge on the Megohm setting on the meter, and does not show as a short on any setting. There are 3 x 150 ohm resistors in parallel underneath the diodes that measure ~50 ohms, so that seems right also.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
Yep, the pads show a short.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
Both 2014 and 2011 measure about 900K in a positive direction (+ on the Anode and - on the Cathode) and open in the opposite direction. They are MUR460 diodes.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
D2014 and D2011 (beside it) appear to be shorted (0 ohms in both directions).
D2012 is shorted between the two small pins on top, and connection from each pin to the big tab appears to charge and discharge via the circuit around it depending on the polarity of the meter leads.Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
OK.. The Cathode of D2014 is 0V DC with ref to Chassis Ground.
The tab on D2012 starts at ~3.15 V DC and then starts going down, like a capacitor is being drained.....Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
I'm getting 120Vac in, yes. And the fuses appear to be ok. The voltage across the big filter cap is 165V DC..
I found two connectors at 4:00 from the yellow transformer, that have 5VS,12VS and ground on them. 5VS is zero, and the 12VS measures around 3V..Leave a comment:
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Re: Westinghouse WD40FW2490 not powering up
Thanks, here's a big picture view of the connections, and a couple of closer ones, flash and no flash....Leave a comment:
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Westinghouse WD40FW2490 not powering up
Hi All,
this is a Curbside special, so I'd really like to troubleshoot the issue before breaking down and replacing the main board.
It has an ST6308RTU-AP1 main board, like Seiki, and others, with I assume specific firmware for this particular model of Westinghouse TV. This is an all in one board with both power supply and logic on it.
Here's what I've done so far:
Tried some of the Reset sequences found on other sites, with no success.
Checked for the 5 volt standby voltage as per Bud's troubleshooting doc, not found on the connector...
No activity results to display
Leave a comment: