My new LCD and how do I determine how many amps its pulling?

[diggerdanh]

I mentioned a while back that I had found a nice LCD screen. Here is what I am using, a portable RCA VCR:

http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 85261&rd=1

I bought one that was "broken", the VCR wasn't working. I didn't care, all I wanted was the LCD from it anyway. I got mine at the time for $9.99 + $25.00 shipping. I figured for $35.00 it's not a bad deal. I haven't been able to find another one that cheap since then, though.

It really is a sweet little unit and pretty easy to figure out the pinouts by tracing and poking and prodding with a multimeter. It has a nice little 5.6 inch screen with good resolution. It has a secondary controller board that has tactile switches for volume (which also serve for adjusting tint, color, etc) and select (for switching between tint/color/contrast). The volume, tint, contrast, etc. show up as a bar on the bottom of the screen when you're making your changes (kind of like your TV at home)! I though that would be a nice touch on a portable.

First thing I did was pull off the casing and all the VCR crap. After spending some time with it I've got all the pinouts and everything figured out. Right now I've got it torn down to 3 pieces - the lcd with it's controller board, the primary board for the VCR unit (which includes the primary A/V in for the unit. power in, headphone jacks, etc) and the secondary controller board. I have it figured out how I can bypass the main system board by wiring the secondary controller board directly to the LCD controller board, skipping the connection to the main board. I've also figured out the power connections, composite audio/video connections, etc. So I should be able to get rid of the main system board soon.

One of my next step is to do just that, but this past weekend I wanted to take care of some other things, like getting what I currenty have running off batteries. I was able to get it running well off 5 AA's (not rechargeables) so it worked at 7.5 volts, anything less and the sound would fade or get garbled. It may work better once I get the main board out of the picture, it seems to be "wasting" a lot of the power. It is running, but it seemed to run down those batteries quickly. I may have had crud batteries, though. I wanted to check how many amps the thing is pulling so I can figure out what kind of batteries I am going to need. I may also look to see if I can do the LED mod, but I haven't done one before, so I'll be going in blind.

I remember a post before where Gannon or someone explained how to figure out how many amps something is pulling, but I did a search and can't find it. Can someone give me a quick primer so I can do so? Thanks.

As I said it's a nice little screen and I end up spending half my time that I'm "working" on it actually playing Galaga on my SuperJoy III that is hooked up to it. I will probably end up tearing that SuperJoy III down and combining it's parts with the screen to make a little portable NOAC. There is plenty of plastic casing left over from the portable VCR so that should provide lots of material that I can hack up for creating a case.

I'll post some pictures soon of what I have it broken down to so far.

[Admin, you may want to move to Pocket TV Hacking. Sorry, I originally meant the post to just be a question about how to figure out the amperage draw, didn't mean to get into the full description of the LCD and its functionality.]

[JackFrost22]

Use a clamp meter thats what I always do

[stereth]

Hook up a multimeter in series with your power supply.

[JackFrost22]

I never thought of that a clamp meter requies no aligator clips or soldering thoguh you need on lying around thoguh