Re: Vizio E601i-A3 top half of screen dim
Was this ever resolved? I am seeing the same issue and swear it is a diffuser issue
brnrubbr
Member
Last Activity: 09-22-2023, 10:39 AM
Joined: 06-11-2013
Location: Hilliard
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Update after a long while.
VSCAN was acting really wonky. It initially looked like I had a signal on startup, but then the IRFP4332 would escalate to 190 degrees F and then VSCAN would shut off.
This is when the investigation really went sideways on this project. I replaced all the IRFP4332 components on the Y-Main and all the results were the same. Fun fact, I think I damaged the TO-247 Heat-transfer pad. One of the IRFP4332 shorted out like a shotgun........ so that was fun....Last edited by brnrubbr; 10-03-2018, 07:13 AM.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
X-Main
VCC = 15.1VDC
Vss = 209
Y-Main
Va = 54.7VDC
Vc = 15.1VDC
VS = 209VDC
Logic Board
D5.3 = 5.2VDC
Do we know what IC or logic is controlling the FETs and what input/output is expected at the FETs?Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Oops, Q5008, Q5011.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
A whopping 0VDC (zero VDC) at both test points. It is verified with a multimeter.
I also found U5008 and U5011 hot as hell too (190 degrees F) after a couple minutes. So a few more IRFP4332 FETs are on order from Mouser.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
A bump to keep it fresh
Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
One O-Scope of varying sizes and degrees in the workshop....Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Ask and Ye shall receive!...Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
All fuses on X-Main, Y-Main, Logic Board, Z-Buffer(?..... along bottom of TV) are all good.
Yeah, I have access to an O-scope. Where shall I check?Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
X-Main
VCC = 15.1VDC
Vss = 209
Y-Main
Va = 54.7VDC
Vc = 15.1VDC
VS = 209VDC
Logic Board
D5.3 = 5.2VDC
[B][U]BIG UPDATE[/U][/B] - After replacing the IRFP4332 FETs on the Y-Main, now I do not even get a flicker on the screen.
- [B]Neither [/B]IRFP4332 FET is getting warm now.
- Found bottom-most Buffer U5407 @ 115 degrees F. Hot, but not hatefulRe: PN50B450 - Turns on, Sound good, ILeave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Ask and ye shall receive. Still no Test Pattern, the included photo is what I did per instructions.
I received the Y-Main repair kit and have begun replacing sets of FETs. So far, I have replaced both IRFP4332 and the one in U5407 still gets ridiculously hot....Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
No test patterns were observed.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Here go!
...
Last edited by brnrubbr; 09-17-2018, 06:18 AM.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Does the LED blink on your control board at a rate of about once a second?
[B]Yes
[/B]
You say you have backlight, while plasma TVs do not have a backlight they do have a minimum discharge level, so can you see a small amount of light from the screen in a dark room?
I'll edit the Backlight comment. [B]Yes, I see a small amount of light on the screen in a dark room[/B]
Edit: Can't edit previous posts :-(Re: PN50B450 - Turns on, Sound good, I think Backlight is good, NoLast edited by brnrubbr; 09-16-2018, 09:33 AM.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Per.....
[url]https://www.youtube.com/watch?v=sNZVkuh2Ajk[/url]
I've verified none of the Y-Main Buffer ICs are dead-shorted
Hooking everything back up on the Y-Main, applied power, and used a IR Thermometer......
- Found bottom-most Buffer U5407 @ 115 degrees F. Hot, but not hateful
- All other Buffers were room temp (i.e. not being powered)
- ***Found the middle set of FETs (903188, STTH40P03S, STTH40P03S, IRFP4332) VERY hot. I read...Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
X-Main
VCC = 15.1VDC
Vss = 209
Y-Main
Va = 54.7VDC
Vc = 15.1VDC
VS = 209VDC
Logic Board
D5.3 = 5.2VDC
Again, to recap.... the screen flickers snow on startup and shutdown. Sound is good, display is not during normal operations. Any additional thoughts regarding troubleshooting would be a huge help.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
No obvious popping nor venting of any component. If anyone knows where I can get a troubleshooting manual for the TV, it would be a huge help.
I'll verify everything on the manual below........Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Well...... shucks. All 4 FETs replaced and TV still isn't working. The suspected FET did smell a little smokey, but the TV still isn't working.
I'll take a closer look at the Y-Main and see if any of the buffers may have popped.Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Kit is on order. Thank you so much!! I'll try and update when everything is repaired and resoldered. Thanks again!Leave a comment:
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Re: PN50B450 - Turns on, Sound good, I think Backlight is good, No Picture
Moar updates.....
X-Main
- "Cold" solder joint picture included
- No obvious burn marks, cracks, or heat-spots on PCB
Y-Main
- It looks and smells clean.
- No obvious burn marks, cracks, or heat-spots on PCB...Leave a comment:
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