Re: Vizio VW42LFHDTV10A
New problem...built the circuit, works 100%!! However, fix one problem to find two more. No HDMI's works on the main board. The RCA connector's for AV1 & 2, they work...however, I get somewhat of a fizzle pop every so often and it makes the screen go black. Something to do with the top inverter, seems to stop the longer the TV is on. I swear!! Finally get around to fixing it, after RO said to keep it, LOL...I'm batting 1 and 1000.
But just to let others know, that have read this post...Bud's design DOES indeed work for the delay.
Chancey
Member
Last Activity: 10-31-2012, 08:13 PM
Joined: 08-30-2012
Location: Ozark, AR
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Re: Vizio VW42LFHDTV10A
A1 goes through something similar but with a lot more electrolytics and only one transistor. The RO told me to hold off and wants me to wait on modification. Other than charging for board replacement...IDK man. I learned A LOT in this short time. Mainly, steer clear of Vizio ;-)Leave a comment:
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Re: Vizio VW42LFHDTV10A
I'll get to that one tomorrow...been busy. Made a nice circuit with ACAD from your drawing. Debating on SMD for all except 2n2222. Small and out of the way...Leave a comment:
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Re: Vizio VW42LFHDTV10A
Did I say that I sucked it up in college on AC and transistors? I'm learning...Leave a comment:
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Re: Vizio VW42LFHDTV10A
In the first schematic, wouldn't that turn the backlight on with TV in standby? Or the inverter will always be high waiting on the power button to be pressed with 5vstby going through the 1k resistor before the collector? Just curious if i was viewing that correctly...I realized that the 24v will not be present until PS_ON is satisfied.Leave a comment:
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Re: Vizio VW42LFHDTV10A
Kind of curious if I need to build the inverter...that pin doesn't go HI till power switch is pressed. I think I understand what you're talking bout doing...cut the trace on A1 leading to inverter, re-route that trace to PS_ON, pull wire from main board for PS_ON from J1 and reroute that wire to transistor inverter with time delay for A1/Vonoff on LG Inverter. Time delay relay's though...would they function at such a low voltage? Or pull off 12v feeding back to main board and use the old PS_ON wire as common and wire A1 with N/O side of delay?...Last edited by Chancey; 09-06-2012, 04:51 PM.Leave a comment:
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Re: Vizio VW42LFHDTV10A
C1 is not populated...pin 14 (status)
Removed Inverter board to see silk screen...
Pin 13/B1 - Vbr-B
Pin 12/A1 - Vonoff
Ironically, A1 was the pin I was jumpering off of.Leave a comment:
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Re: Vizio VW42LFHDTV10A
:/ I'm at a loss for the signal flow of power on and the inverter on. I understand what you described, as the sequence of event's and possibly the time delay fuses slowing how the system powers up. But, I cannot use A1 if it's brightness right? Because that would cause the system to be unstable or even power off if they lower the brightness of the TV. As far as building a circuit, I could possible do that fairly easily. Where would be the first place I should look, I cannot get the heat sink off, so finding a datasheet for that CPU to find INV_ON wouldn't...Last edited by Chancey; 09-06-2012, 02:42 PM.Leave a comment:
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Re: Vizio VW42LFHDTV10A
Ok...from what I have gathered by checking the traces, over and over again...your diagram is 100% dead on. The signal is not comin from the processor through R4...on or off. I have read in other post's to trace power on switch to CPU to make sure the correct voltage is getting to the CPU to toggle that input. Other than that...I'd say the main board is dead. All roads lead back to the CPU...budm, by far, you have to be one of the most knowledgeable individuals I have had the pleasure to communicate with and I thank you for your time. I'm gonna look and see...Leave a comment:
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Re: Vizio VW42LFHDTV10A
Sorry...posted without including the pdf I found....Leave a comment:
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Re: Vizio VW42LFHDTV10A
Ok...I think I understand that, takes one to be saturated for the next one to work.
Ok, my findings are:
Voltage isn't coming from CPU (wish I could get the heat sink off to see which pin it goes to, but looks like a BGA), it looks like it is coming from the out2- on the audio amp at 3.3vdc. Not sure if that's suppose to be the trigger...but I have some concerns about that. The voltage is stepped down to 1.5 when off and shows short when set comes on (where the trace goes to the CPU)
The voltage readings on Q32 Emmiter to Base...Last edited by Chancey; 09-06-2012, 11:15 AM.Leave a comment:
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Re: Vizio VW42LFHDTV10A
So basically, it's a complex NOT gate. Checking the voltages...will edit this post to give readings.
Making new post so it will bump...Last edited by Chancey; 09-06-2012, 10:52 AM.Leave a comment:
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Re: Vizio VW42LFHDTV10A
ok...traced it back.
R3 - 553 ohms
to the collector of Q1
Collector to base measurement, on diode scale, show's .500 (maybe good)
I'd say that Q1 and Q32 are setup in a push pull, but cannot read the writing on the face of the surface mounts to tell if PNP and NPN. Q32's Collector traces out to Q1's Base. Traced the Emmiter on Q1, it ties to the collector on Q1 and passes back to R315. Ironically, R315 ohms out to 666 ohms. ?! You can see on the picture's I included...
Just checked where the trace goes under...Leave a comment:
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Re: Vizio VW42LFHDTV10A
WOW!! LOL, I feel a tad in over my head...but, will force on through the madness and try to whip this puppy. Thnx budm...I'll report back what I find on the main board. Little overwhelming...only a hobby repairer
Leave a comment:
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Re: Vizio VW42LFHDTV10A
Would it help if I took some pictures of the inverter board? To determine whether or not it's PWM or analog...the diagram may help. But I may end up having to remove the main board and tracing where pin 1 originates from. At somewhat of a loss...Leave a comment:
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Re: Vizio VW42LFHDTV10A
I agree with the calculations...just wanted to clarify that the first readings were indeed correct and 0 volts. (Post #4)
On the second part, negative ghost rider...power off, no 12v or 24v. Power on, voltages are present.
You are talking about J1 for 12v and the plug going to inverters for 24v, right? I attached picts...
I can program and Allen Bradley PLC5, SLC500 and ControlLogix with my eyes shut...but for some reason, this is kicking my rear....Please don't take my humor as harsh, I am very appreciative...Last edited by Chancey; 09-04-2012, 01:21 AM.Leave a comment:
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Re: Vizio VW42LFHDTV10A
Ok...I need to go to DMM reading class. My meter isn't autosensing and pins 1-2 on U44 are 300 ohms.
R478 300 ohms
R479 1.99K (2K)
C217 1.14K
The initial readings of U16 and U44, PS unjumpered are zero on all pins. The voltage readings I gave after intial readings are with me jumpering the A1 on the PS to J1 pin1. So, factory setup...those two IC's have no in, adj or out voltages....Last edited by Chancey; 09-04-2012, 12:24 AM.Leave a comment:
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Re: vizio plasma
I agree with retiredcaps...I repaired a Toshiba 42" a week ago and spent $40 when I had a feeling it was the IGBT pac that went bad. $15 for the 13pin IC...I got a fuse and an old IC for $40. I payed to learn a lesson......Leave a comment:
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Re: Vizio VW42LFHDTV10A
Best guess from anybody would be better than what I have. Trying to help out a 75 y/o man on SS without having to buy him a new main board.
BTW, off subject, LOVE the site. Never seen so much information with this high success rates. If I get this fixed or not...gonna def donate to the sites fund.Leave a comment:
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Re: Vizio VW42LFHDTV10A
With system jumpered:
U16
pin 1-11.44
pin 2-0
pin 3-5.01
U44
pin 1-8.43
pin 2-9.69
pin 3-11.46
Resistance readings:
U16
1-2 I stopped @ 10k...acted like charging a cap
2-3 2k and rising, cap again
1-3 15k and rising
U44
1-2 .300 ohms <----maybe??
2-3 18.4k steady
1-3 5.4k and rising
Uncertain with the IC U44 being .3 ohms without looking at the datasheet. What gets me, and also worries me cause I know it will cause...Last edited by Chancey; 09-03-2012, 11:13 PM.Leave a comment:
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