Re: Need help with my 900G
PlainBill
okay I will see if I can figure out how to check those circuits.
Thanks
oldmanjohnson
Member
Last Activity: 12-15-2010, 11:28 AM
Joined: 10-24-2010
Location: Parma, MI
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Re: Need help with my 900G
PlainBill
well my ccfl survived the high voltage zener. Got the 7.5's in yesterday and now have the correct zener in place.
Also I have been looking through each of the links you posted for the schematic for the Astar LTV-20pw tv and haven't been able to find one. So I started accumulating the data sheets for the chips on the board that are in the vicinity of anything related to sound. It looks like every component in the 400's is related to sound somehow. I checked voltages in and out at the sound and amp chips and they are correct....Leave a comment:
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Re: Need help with my 900G
PlainBill
Thank you for all that info. I will have to spend some time now going through it.
I truly appreciate your assistance.Leave a comment:
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Re: Need help with my 900G
Does anyone here know where I can find a schematic for a 20" Astar LCD TV?
A friend of my daughter gave it to me and the only thing wrong with it is no sound.
I opened it up and can't see anything obvious so I need to do some tracing.Leave a comment:
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Re: Need help with my 900G
PlainBill
I checked the voltage across the zener and it's 11.54. Then I turned the house inside out looking for one of a lower rating and came up empty handed. I guess I will just have to take my chances with it and order what I need. I do have another ccfl chip just in case.
Should that voltage properly read 7.5 if I have the correct zener?Leave a comment:
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Re: Need help with my 900G
PlainBill
Okay I will put this thing back on the bench and check that voltage and get back to you.Leave a comment:
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Re: Need help with my 900G
Well I spoke too soon. About an hour after I said it was gone it came back. Now it hasn't gone away again all day.
It's the craziest thing in that it looks like a piece of thread stretched across the surface of the screen. When I put the mouse pointer on it, it's actually under the line. It's weird looking 3 dimensional. LOLLeave a comment:
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Re: Need help with my 900G
Hey the line went away.
I got up this morning and played a little free cell. Went online to see if there was a reply to the previous post and while I was looking for some info the horizontal line just disappeared.
Any reason for me to be concerned? Does anyone know what caused it?Leave a comment:
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Re: Need help with my 900G
PlainBill
well I replaced the defective zener, brown green green, with the only one I could find, red red green, attached to one of my used circuit boards.
I am typing this post using the monitor that has been down for weeks.
THANK YOU, THANK YOU, THANK YOU and to all the others that worked patiently with me through this.
Now I just need to figure out why I have a horizontal line across the middle of the screen. Go figure. LOL
Do you have any ideas what could be causing this? Is it because I used a different zener?Leave a comment:
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Re: Need help with my 900G
PlainBill
Thank you for all the great info especially the schematic.
I checked the zener diode off board and with my volt meter set to diode test, with sound, I get continuous noise in both directions. Does that mean it's bad? Also how do I decipher the color bands on the diode? Green, green, brown.Leave a comment:
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Re: Need help with my 900G
Plain Bill
I checked all that you requested and marked the board.
You will notice that I accidentally put a yellow dot on pin 9 but please note I dropped the dot early and my eyesight deceived me. My voltage checks were in fact on pin 6 and pin 10 as requested.
The cap in the blue circle isn't showing any voltage on the one side on or off. Is replacing that as simple as finding one of the same color on another circuit board? I have no idea what the rating is and I don't have a schematic. I ordered one from schematics dot me and it...Leave a comment:
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Re: Need help with my 900G
Plain Bill
okay this is the best image I could get out of my camera with my 50 yr old nerves.
When you say, "the inverter controller", are you referring to the ccfl chip? If so that number is BIT3193G....Leave a comment:
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Re: Need help with my 900G
I wondered about that myself but kept watching it until I saw the word windows in the box. Also when I turn it on, and it's connected to my laptop, the power light turns on blue for 10 seconds and then turns yellow. Then when I press the keys to shift the video to the external monitor, the monitor immediately turns the power light blue and stays that way until I exit external monitor mode.Leave a comment:
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Re: Need help with my 900G
Here's the latest info with my 900G headache.
I replaced the mosfets and the ccfl chip and I'm still not getting the lamps to fire. With it hooked up to my laptop I can see the screen with a flashlight which it was doing before I changed the chips. I have checked all fuses on each of the circuit boards and all check good with my volt ohm meter set to diode test with sound.
How should I proceed from here?Leave a comment:
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Re: Need help with my 900G
Here's the latest info with my 900G headache.
I replaced the mosfets and the ccfl chip and I'm still not getting the lamps to fire. With it hooked up to my laptop I can see the screen with a flashlight which it was doing before I changed the chips. I have checked all fuses on each of the circuit boards and all check good with my volt ohm meter set to diode test with sound.
How should I proceed from here?Leave a comment:
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Re: Need help with my 900G
Okay I checked the mosfets on board and I had to set the meter to 20m to get a reading. So I took one of them off the board and got the same results. I decided to just go ahead and order the mosfets and the ccfl chip. Figured for what they cost I might as well change them and see if that solves the problem.Leave a comment:
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Re: Need help with my 900G
I'm sorry I thought I could just plug in the monitor turn it on and if it was working I would at least get the missing video message. So all this time that was what I was looking for as I worked on it on the bench. I did try hooking it up a couple of times but it was always the same as on the bench.
Also I did hit the reset button on the computer while it was attached and I didn't even get the DOS screen. The whole time it was showing that rectangle moving around like a screen saver.
Should I still test the mosfets?Leave a comment:
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Re: Need help with my 900G
Okay I checked the red circle on the right, which is a fuse, but the red circle on the left is a resistor.
I also checked all the fuses on that board and they check good.Leave a comment:
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Re: Need help with my 900G
Okay I have more new activity.
I decided to hook the monitor up to my computer since it was acting more like it used to with the power light.
When I connect it to my PC and turn it on the light stays blue, sorry not green, and when I put a flashlight next to the screen I can see a rectangular screen saver running with some test on it that I can't read.
What is this telling me.
I'm so close to getting this thing running I'm about to wet myself. LOLLeave a comment:
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