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Topic: Harvesting from portable LCD tv (Read 1 time) previous topic - next topic

T_Lex

Hello,

I have one of these:


It is a 2.2 inch portable LCD TV from the mid-90s.  It was pretty cool back in the day!

As I recall, the LCD actually worked when we last tried it, but there were tuning issues.  And now, with the digital tv signals, it really doesn't work.

Anyway, I opened it up and it has all this stuff:




It is the same as this:
http://support.radioshack.com/support_video/68879.htm

Which has a parts list
http://support.radioshack.com/support_video/doc68/68880.htm

Couple questions:
- I'm particularly interested in any inductor/electromagnetic elements, but I don't have the expertise to figure out if there is anything there.
- I'd love to get the LCD working with the Arduino, so if someone can handicap the odds of that, it would be great.
- I got the wires loose with my soldering iron, but the little rivet-like solders on the back of the board are... problematic.  Any tips on how to get those loose?  (I see a coil on the board that I'd like to try as an inductor.)

TIA,
T

cr0sh

1. I can't see anything on that board that would be worth the time or effort desoldering...
2. Any chance of getting that LCD to work with the Arduino is likely low, unless you can obtain a datasheet for it
3. Do you have desoldering braid, or a solder sucker (plus picks and such)? Without those, desoldering parts will be at best an exercise in frustration...

Regarding the LCD - any chance of using it likely went out the window once you started removing wires. I be very curious as to what is on the other side of that PCB; I'm also curious as to where the controller for the LCD is located at (if it is a part of the LCD PCB - that's better, but you're gonna want that connector for the ribbon cable). You need to identify what the LCD part numbers and such are (you might also try doing some googling on the LCD TV model number itself to see what comes up); if that fails to turn anything up, then the part numbers and such for the controller ICs are the next step. Another problem you're going to run into is not knowing what the voltages and such the LCD and backlight expect (this is why, before you start tearing thing apart, you need to do research and maybe throw a scope or meter on parts if they work at all, while taking a ton of notes, and pictures, and labeling things). Even with all of that, it may just be a bunch of dead ends; the parts may be OEM/house marked and made or marked exclusively for Thompson (Panasonic?) and impossible to decipher (and forget about getting help from any company today).

I'm curious what you expect to be able to do with any of the coils on the board (that you couldn't do with other means)? I mean, what do you expect to -do- with one of those inductors (I guarantee you it won't work well as an electromagnet)?
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

T_Lex

Thanks for the info!

In terms of the LCD, I'd done a bunch of research, and not found anything.  So, part of the reason for taking it apart was to get a better idea what it was made of.  Good point about running a meter for information before desoldering.   :~

I'm pretty sure this is a generic device, that companies just re-badged.  Thomson/RCA was the branding on this one, but it also looks like "Optimus" (Panasonic?) had the same thing.

The parts list has 2 different "crystal" references, with different hz references.  I've lightly googled that stuff, but not very deeply.

As far as the LCD goes, the PCB part just clips in, and there isn't many markings on it.  I haven't tried to get under the shields.

In terms of desoldering, I dont' have any of the things you mentioned, but I can spend a few bucks on flux and the braid, and such, if I could get something decent out of it.  Especially since it appears that I may be getting into this hobby more.

In terms of the coil, I've a project that is a variation of the Regulated Positive Voltage Booster project in the Playground.  It calls for an inductor.  I have a homemade one, but would be very interested to compare it to a "real" one.

Thanks again!

cr0sh


Thanks for the info!

In terms of the LCD, I'd done a bunch of research, and not found anything.  So, part of the reason for taking it apart was to get a better idea what it was made of.  Good point about running a meter for information before desoldering.   :~

I'm pretty sure this is a generic device, that companies just re-badged.  Thomson/RCA was the branding on this one, but it also looks like "Optimus" (Panasonic?) had the same thing.

The parts list has 2 different "crystal" references, with different hz references.  I've lightly googled that stuff, but not very deeply.

As far as the LCD goes, the PCB part just clips in, and there isn't many markings on it.  I haven't tried to get under the shields.


About the only way you'll get the LCD to work with the Arduino without a likely fruitless search would be to somehow inject a composite signal into the circuit; this wouldn't be easy, either, as finding the point to inject at would be a matter of having a schematic (or reverse engineering one), as well as an oscilloscope (and a good working knowledge of how TV and video work). If you were lucky, you might find something on the internet about connecting a composite video source to it as similar LCD displays were used in the 1990s for homemade virtual reality HMDs (head mounted displays), so maybe someone out there documented a solder point on the PCB for that TV (long shot, though). If you could find that point, then you could (potentially) connect it up to the Arduino using the TVout library.

Of course, desoldering any components will make the above a moot point...


In terms of desoldering, I dont' have any of the things you mentioned, but I can spend a few bucks on flux and the braid, and such, if I could get something decent out of it.  Especially since it appears that I may be getting into this hobby more.


For single-part desoldering, you mainly need desoldering braid, a desoldering "pump" (or "pen" - depending on how you define it), and a desoldering "bulb"; flux rarely comes into play (it's mainly used to make soldering easier). Whatever you do buy, try to purchase the best you can afford; electronics as a hobby is fairly cheap when it comes to parts - it's the tools that can be expensive, but generally quality tools are the ones that really cost - so try to get the best, as they tend to last the longest.

That isn't to say you need to invest -now- in a Fluke or anything, just try to get something better than an el-cheapo Harbor Freight weekend special (although you might want to "stock up" on these throw-away meters; they aren't -that- bad, and are great for when you just need that extra measurement, and you don't care about extreme accuracy, or if you are in a situation where you don't want to run the chance of ruining your "good" meter).


In terms of the coil, I've a project that is a variation of the Regulated Positive Voltage Booster project in the Playground.  It calls for an inductor.  I have a homemade one, but would be very interested to compare it to a "real" one.


Oh - ok; in that case - you might want to invest in an LCR meter as well; these are meters designed to measure capacitance and inductance, as well as resistance - and can generally do a much better job on the L/C portions (inductance and capacitance respectively) than a multimeter with those capabilities can (although you can certain find quality multimeters with such better capabilities, but they can be mighty pricey!).
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Osgeld

#4
Mar 15, 2012, 11:24 pm Last Edit: Mar 16, 2012, 05:17 am by Osgeld Reason: 1
something I did ...

http://hackaday.com/2011/10/03/hack-a-watchman/
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

Techone

@Osgeld

Thanks for the link. The site have a link for a video chip. Video In - RGB out. Just perfect to hack the LCD panel I have here. 

@T_Lex

You have to identify the pins. Base on the LCD panel I have, I have : R - red video , B - Blue video, G - green video, Sync , Contrast ? , Brightness ? , NTSC - PAL select, + 5 ? , +12 ? , of course a GND.  The pins on my display has been identify and confirm. So I count 10 pins. How many is yours ?

Osgeld


@Osgeld

Thanks for the link. The site have a link for a video chip. Video In - RGB out. Just perfect to hack the LCD panel I have here. 


I have yet to find that chip in the wild, its old ... (that was my hack btw) I have a use for it as well, I have a big nasty NEC multisync (for the sake of simplicity lets call it a model 1) that is ttl or analog RGB and supports everything from NTSC to 800x600@56 hz VGA ... really 640x480 @ 60 hz vga but you can push it, anyway I want this chip to provide a composite to RGB conversion for my retro computers. Then I can just make a video switch and have one screen for all the computers in my collection. It has been so tempting to just yank this thing out of the watchman, BUT I would LOVE to find a similar part that is still available for other people (apple and commie people especially have RGB monitors for their macs, GSes, and Amiga's, and want to plug a // or a 64 into them cause the picture quality is fantastic)
http://arduino.cc/forum/index.php?action=unread;boards=2,3,4,5,67,6,7,8,9,10,11,66,12,13,15,14,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,86,87,89,1;ALL

T_Lex


@T_Lex

You have to identify the pins. Base on the LCD panel I have, I have : R - red video , B - Blue video, G - green video, Sync , Contrast ? , Brightness ? , NTSC - PAL select, + 5 ? , +12 ? , of course a GND.  The pins on my display has been identify and confirm. So I count 10 pins. How many is yours ?

heh heh

Well, it has a flat "cable" that looks to have 15 connections.  It looks like I'll have to do some de-soldering/breaking of stuff to remove the heatshield to see what the board looks like that is directly connected to the LCD.  I'd be thrilled to even be able to turn it on and off, but I don't have much time to devote to this project.

Thanks for your info!

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