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Topic: LCD Backlight Inverter (Read 820 times) previous topic - next topic

Goofballtech

I have scavenged a densitron LCD from another piece of hardware. I also grabbed the LCD ballast from that assembly.

I got it all working good using individual power supplies. Tested good on the display and the backlight.

I attempted to tie them all to my TPM 30105 whicich for some reason was outputting 8Vdc instead of 5vdc. My backlight inverter (DAS5V13) did not like this at all. It worked for a few minutes then went dark.

Before failure i had 5VDC on the input side and 300VAC on the output to the LCD. Now i have 120VAC on the output and no light.

I have been searching for a replacement for the inverter with no luck. My experience with these is limited to the research i did to make this rig work.... My question is, how would i cross reference this to a compatible replacement?


floresta

Quote
I have been searching for a replacement for the inverter with no luck. My experience with these is limited to the research i did to make this rig work.... My question is, how would i cross reference this to a compatible replacement?


Your best bet is to find someone who has a cigar box (remember those?) full of them stashed away somewhere.  Unfortunately many of those people are like me and can't remember where the cigar box is.  If I find mine I'll send you one.

Don

Goofballtech

In looking for a replacement for this i have found a few potential CCFL inverters that output between 275 and 350VAC.

Do you think any of these would work or would it not be worth the attempt to potentially burn out the existing backlight?

Docedison

If you look at the data sheet for the LCD you should find absolute max and operating currents for the CCFL or EL device, the rest is a no-brainer. Besides Displays are really cheap and could that one be really worse W/O a light to see what is happening... I have 3 or 4 EL type backlight type LCD's and I think that even though they look real good and are going to be used a a Mains operated device... I'd rather not have to make inverters for or buy for the oddball devices... Dimmable ones are not really inexpensive and the 555 based inverters don't dim real well as they are 12V devices...
Too much work when I can buy a complete Color graphic LCD for < $20.00 US with shield... Itead 3.2" W shield from Ellectrodragon $13.20 + $5.90 = $19.10 and ~$23.00 for the really nice one
Which is just about what it costs for an LCD on Ebay alone W/O shield.

Doc
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"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

Goofballtech

Thanks for you comments.

I really don't have a data sheet for the LCD itself. I know it was made by Densitron due to a sticker on it but beyond that there were no identifying markings. I managed to get it running by identifying the controller chip and a lot of ohming traces.

I will be using this in potentially unknown lighting condition and the LCD will be remaining in it's original case. The rest of the case has been re-purposed but the screen is form fit to the top of the case and the mounting screws all line up... that's really the only reason i care for this specific display.

Essentially what i will be doing is taking an old control station from work and making it into a smaller form version of the same thing. kind of a "display" model if you will. I can't do that with the OEM boards but i would really like the general interface to be the same and that's one of the main reasons i was looking to keep the original screen instead of getting a known value of an off the shelf model.

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