Re: Sanyo DP46840
You have a good point. I just got my second meter out to check, and it appears that I have a gremlin.
The 7V I got at the Pwr SW (Pin 1 K8B) is now intermittent after being very consistent all day... I did manage to verify that both of my meters read with 1/100 of each other. However, I did NOT manage to verify the 7V at pin 1 with the second meter.
The 5v StdBy was verified with the second meter to read 7.73VDC. The first meter read 7.74VDC. The first meter is a Fluke model 25. The second meter is a radioshack 22-805....
JadeMattican
Member
Last Activity: 12-01-2015, 08:09 AM
Joined: 12-21-2010
Location: FL, USA
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Sanyo DP46840
Here's the scenario. I'm working on a Sanyo DP46840. It was free, minus the cost of repairs... That said, when the power button is pressed, the green LED come on for a few seconds and goes off... I'm working from the service manual I found [URL="http://www.toms-service-manuals.com/getfile.php?req=Sanyo_DP42840_P42840-00_N7AL_%5BSM%5D.pdf&mfg=Sanyo"]HERE[/URL] (PDF DOWNLOAD LINK)
Page 4/5 of the manual deals specifically with this issue, "Power LED turns OFF within 10 sec of Power ON, or LED cycles ON & OFF"
Step one is to check for 5V to "Power_SW"... -
Re: Insignia NS-LTDVD20
B-on shows 5.6 V DC when the tv is turned on, but the backlights only flicker on for about a second or so.
B-on shows 6.1mv DC when the screen is off...
So... Bad backlight inverter board? Could it be the caps on the inverter board are bad? They are TF brand 25V 330uf.Leave a comment:
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Re: MAG Innovision LT716s 700p 2 Seconds To Black
1. Can CCFLs Be Intermittent?
2. I no longer think the CCFLs are the issue. I'm now thinking either power, or bad wiring...
I was playing with the CCFLs again, and this time, the bulb that I determined to be bad, worked... but a different bulb was "bad." After much rearranging of the bulbs, it's now working... It remains to be seen for how long.
I stand corrected. It just shut down as I was typing, and is now back to 2 seconds to black. (Probably lasted about 2-5 mins.)...Leave a comment:
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Re: Insignia NS-LTDVD20
Attached are 2 pics of what I'm assuming is the inverter board for the backlights and another pic of the power board where the output voltage is.
I've checked the voltage and it appears to be putting out what it's supposed to.
As to the B-On pin... Should I be testing it to a ground? What kind of reading should I be getting there?
I've been messing around with the backlight inverter board with my digital multimeter... Correct me if it's not a transformer of some sort. (See the first 2 pics.) Each transformer has...Leave a comment:
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Insignia NS-LTDVD20
When the screen is first powered on, it shows a picture for about a second and goes out. There is still sound, and if you shine a light on it, you can see the image... I decided to treat this like a 2 seconds to black issue, despite the fact that it's definitely shorter than 2 seconds... That said, I started with the power supply...
The P/S P/N is DTV207.
My opinion is that the p/s is shot. (See Attached Pics.)
First, there is a chip on the bottom of the board that looks kinda melty to me. There is also, solder bridging a total of 5 of the 8 pins on the same... -
Re: MAG Innovision LT716s 700p 2 Seconds To Black
I switched the connectors around and the same bulb was dim/darker than the others. Thanks for the advice about buying a second bulb for testing purposes. Mostly I work on software issues. This is the most in depth repair I've ever undertaken, but I love to fix things. If it works, I'll start repairing more...Leave a comment:
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Re: MAG Innovision LT716s 700p 2 Seconds To Black
Bad idea tyring to take pictures of bright lights...(Might as well have spent the time trying to take pictures of UFOs or bigfoot... No offense to anybody who has seen either.
I believe that the CCFLs are the main issue. I will test the transformer while i have it open & attempt to replace the bad bulb (Just as soon as I can figure out what size I need.) If changing the bulb goes well, then I'll try to recap it just to make sure there are no further issues...Leave a comment:
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Re: MAG Innovision LT716s 700p 2 Seconds To Black
Many thanks for the link...
Here's an update with pics... Why am I so easily amused?
The first pic is the screen with a led flashlight behind it. The second pic is the screen with a fluorescent bulb behind it... Simply put, it works... Sort of. The third pic is just to show how far disassembled the screen is.
On another note, of the 4 CCFLs, 1 of them does not seem to be quite as brite as the others... It's just barely noticeable though. I'll try to get a pic of it... 2 seconds isn't a lot of...Leave a comment:
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Re: MAG Innovision LT716s 700p 2 Seconds To Black
@ RetiredCaps
As to the readability note, it's a habit that goes back a ways... I'll try to refrain.
The display was the default Win7 Pro background. And, yes, I do have an old digital multimeter. As far as I know, it still works the way its supposed to work. I've never tested a transformer, but will try it & let you know the results.
@ Eguevarae
I figured as much about leaving the signal board alone, but wasn't sure. Assuming the transformer tests ok, then I'm off to buy new...Leave a comment:
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MAG Innovision LT716s 700p 2 Seconds To Black
First Off, This Monitor Was A Freebe & I Do Not Know It's History Other Than The 2 Seconds To Black.
What I'm Posting For Is An Opinion. Should I Replace ALL The Caps On BOTH Boards? Or Should I Just Replace The Caps On The Power Board.
Yes, I Have Looked At The Troubleshooting Guide For 2 Seconds To Black By RetiredCaps @ [URL="https://www.badcaps.net/forum/showthread.php?t=10419&highlight=seconds+black+guide"]https://www.badcaps.net/forum/showthread.php?t=10419&highlight=seconds+black+guide[/URL]. There It Mentions, "You turn on your LCD...
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