Re: Rca LED50B45RQ no picture, sound, backlight.
I'm having the same problems red light when it's plugged in and then blue light stays on screen stays dark can't see menu images anywhere inside . back lights to come on and no cats seem to be to blame . I've taken off the t con board which I've read needs replacing but what could really be wrong with it ? its not eprom, and I have done some reflowing to the memory and main processor chip and get results seeming im getting closer. i used to get blue light for a few seconds now it stays on. I will post results from next flow. so many...
MBAJACE
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Last Activity: 04-04-2016, 12:50 PM
Joined: 06-22-2010
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This is how my screen looks I hope someone can recognize this,, Same thing with all the computers, they all have same desktop though.
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Re: Samsung 205BW bad connection problem?
I have the 205BW with identical problems. The Screen functions perfectly.
I replaced the same 3 caps you identified and it made the monitor power cycle faster than before. 1.5sec flash. Powerlight blinking. I unhooked the ccfls and screen works but is black.
I think the problem is the bulbs, I have an external ccfl inverter and have 4X 15'' ccfls and need 6X 20'' ccfls but can't find. Screen works perfectly just a little spotty.
With the external inverter I could power up ccfls ( the 20'' stock ) 3/4 to...Leave a comment:
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Re: Viewsonic Optiquest Q19wb
I bet it is the bulbs. is there another way to test a bulb. I have a Samsung SyncMaster 205BW that is power cycling. I had a pair of pc mod 12V inverters and tested all of the bulbs. I could light them all about 3/4 of the way down the 18'' bulb. Anyhow I pulled the bulbs out and rigged up 4 ccfls and the screen works fine.
I think the bulbs need 13V to fire all the way up possibly. Is there a way to test the bulbs with a meter? I'm trying to find proper replacement bulbs...Leave a comment:
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Re: Viewsonic Optiquest Q19wb
Anyone have a lamp source?Leave a comment:
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Re: Viewsonic Optiquest Q19wb
The fuse was part of the problem. I don't think its totally fixed but as of now I want to find some replacement lamps...Leave a comment:
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Re: Viewsonic Optiquest Q19wb
I soldered the fuse with a copper bar a few weeks ago and no problems.
I would like to know where to get replacement lamps because thats the only option I didn't try....Leave a comment:
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Re: Viewsonic Optiquest Q19wb
If you're looking at the green side w plug down it is on top left corner.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
OK, thanks on the silver tape info. The fuse was not the problem. I will be putting a new set of caps in on Saturday. Hopefully that fixes it.
Where on the board would its memory be stored?
As a last resort I think I could make some kind of reset switch that drains the power from it faster than 5 hrs.
I will post the picture up soon.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
How much factor is the shielding tape on the back of the lcd panel? I did not measure what comes off but I'm super curious.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
No, I took that radio shack cap out. The 4A fuse is good then and all of the circuitry tested good. The kit I bought off of ebay this morning has all of the caps. The monitor works it just gives me 1 opportunity every 4-6 hrs and it has to stay on. I guess I will start with the caps and go from there. I really want to know how to bypass or trick the circuit with a resister on I think the 7 pin. Any experience?Leave a comment:
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Re: Viewsonic Optiquest Q19wb
It is yellowish on the edge, left I think. So I think the fuse may be the problem. with 0.1 resistance I believe there is a 2V loss and 8V may not be enough to sustain the cfls. I went over the transformer solider and bridged the fuse. Its a slow burning 4AMP and I think it is half way. The green light is blinking so there must be some flux on the board. I'm going to bridge the fuse and see what happens. I'm going to replace caps by Saturday. Whenever they get here.
If I can power cycle on/off/on and keep the backlights on it will be a succ...Leave a comment:
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Re: Viewsonic Optiquest Q19wb
OK I think R805 is actually fine. My meter says its shorted, a solid connection. hmmm.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
R805 resistor red yellow silver gold I think 24.7ohm??? I'm learning.
Ranges from 0.5 to 0.2ohm
F802 Mustard yellow resister? Fuse possibly, reads T 4A so I think its a 4Amp fuse..
Reads 0.5 to 0.1ohm
Everything else checks out I think.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
It just ran again for about 10 min before I reset the settings on graphic card. CFLs are off again. In 5 or so hrs it should work again. I'm getting normal readings on the board. Just to resistors that seem to be shorted.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
BTW I found 2 resistors that were shorted. Make any sense?Leave a comment:
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Re: Viewsonic Optiquest Q19wb
Oddly it was working again and when I tried power cycling it to see if it was fixed it is now back in 2 seconds to black mode. Also it was moved from 1 machine to another. I think it has some kind of memory to it. Is there a way I can bypass the back lights. Hard wire them on? The info is still showing up on the screen if I shine a led at it. All of the bulbs are fine.Leave a comment:
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Re: Viewsonic Optiquest Q19wb
Transformers measure .631 and .635 for 501 and 502 I'm going to do the 8 point check you posted awhile back for an identical power supply from acerLeave a comment:
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