Latest Fiasco: DVD Player Video Out to Antenna In

How about a 78L05 voltage regulator? T)-92 package with three leads. Add a couple caps and you're done. Solder any decent physical size of SMD capacitor to the input lead and the case, then feed the unregulated DC to the regulator at that SMD capacitor. Quick and easy, + very compact and reliable.

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Merry Christmas!

Take care, and God bless.
Michael A. Terrell
Central Florida

Well, you see, that's my whole problem. The wall wart is 6V regulated, and a 78 series reg chip requires at least 2 volts to function. So the supply for the 78L05 has to be at least 7V, plus whatever ripple is there, which in this case is zero.

So to get around that, I decided to lose the 6V regulated wlal wart and use a 6v unregulated wall wart, which is abou 7 or 8VDC. I knew previously that the modulator takes about 24 mA. So I put a 5,1V half watt zener and a 100 ohm wirewound pot in series across the wall wart, and adjusted the pot until I got about 40 or 45 mA thru the zener. I measured the pot and it was about 40 ohms.

SO I soldered the 5.1V zener across the +B and ground pins on the modulator. Then I soldered a 39 ohm half watt resistor in series with the incoming + lead, and put heat shrink tubing over it. The modulator power up just fine, and the incoming video looks good. As a result of losing the 5V power supply, the speckles that were on the screen are now gone.

So now I have a Q & D way of watching the DVDs on my TV. I can't understand why the mfrs don't consider putting in a modulator in their DVD players, but then I guess I shouldn't expect much for fifty bucks.

8-)

ALso I spent quite a bit of time online trying to find the data for a Panasonic VCR "RF Front End Unit", which I believe has a modulator in it. I managed to find a document expaining the codes imbedded in the product ID on the label, but that's as far as I could go. So I know from the codes what the product is called, is for U.S. (no fooling!), has a PLL in it, etc, but I still don't know what the pinout is. I tried tracing down the traces, but they are so small and convoluted, and go under the surface mount Cs and Rs, that I couldn't even find the + supply pin. Maybe I'll fiddle more with it later.

What I got so far is working just fine. And I think after Santa delivers the Xmas presents this morning, there are a lotta people who have brand new DVD players who are going to want one of these badly. I think you can buy something similar at Wal-mart or Target, and if you're lucky you might be able to find one that can modulate the RF with stereo, so you don't have to use a semarate amp and headphones, like I'm doing, since my old TV isn't stereo. Thanks for the help.

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The voice of "Watson A.Name - "Watt Sun, Dark Remover"" drifted in on the cyber-winds, from the sea of virtual chaos...

Sounds like a nice RF Modulator project. I may try to build one of these myself, if I ever need to. My only AV problem right now is having only one on my old TV, or at least until I can built a new AV switch.

As for the Mono TV issue, A cheap stereo amp could be created from a few spare parts to power two small external speakers. The entire works could be mounted in a single case. I don't have any layout plans handy, but you could Google for some.

Another alterative is to just buy a RF Modulator. *Shutter* They're quite cheep these days, probably in the 8 to 20 dollar range.

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Maxwell C.G. Pollare, a "small god" in his own mind...

Use a 9 to 12 volt Wallwart supply with a 5 V regulator, or you can try a series diode.

Put a 47 uf cap 35V or so with a 0.1 uF 100 V cap in parallel, and put this affair in parallel to the voltage supply input to your modulator. Make sure that all your wiring that is handling signals is properly shielded. For the RF and video wiring make sure that the impedance rating and type of the wire is correct. Over a small distance the impedance may not be critical.

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Greetings,

Jerry Greenberg GLG Technologies GLG ========================================= WebPage

Electronics =========================================

I scrounged a Mitsumi modulator out of a VCR player and traced down the pinouts. There were only 5 pins, so I soldered some power leads and coax for the video to the shiny little metal box laying in front of the TV with the coax and wires hanging out of it. I give it 5DVC and it stops passing the antenna thru to the TV and blacks the screen, waiting for the video input. Great! I power on the DVD, and I get video on the TV. The only prob is that the TV has lots of speckles, like snow but with varying patterns, so there's some impulse noise leaking into my contraption from somewhere. I'll have to investigate and deal with it later.

I'm using a 5V 1A PS, but the modulator needs only 30 mA or so. So I want to connect it to a wall wart. I bought several 6VDC regulated wall warts but I checked the specs for the Toshiba chip the modulator uses and the +B calls for 4.75 to 5.25 VDC. So I need to drop one volt, but try to keep the V regulated. I thought about using a 1N4002 rectifier in series for .6 or .8V drop, but I think that it will mess up the regulation and be somewhat temperature sensitive.

Whatever I use, it has to be just a few parts that fit between the pins on the little modulator. I was thinking that maybe I should just use a 9VDC unregulated wall wart, a resistor and a 5.1V zener to make a 5V shunt regulator. What would you do in this situation? Thanks.

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My email address is whitelisted. *All* email sent to it goes directly to the trash unless you add NOSPAM in the Subject: line with other stuff. alondra101 hotmail.com Don't be ripped off by the big book dealers. Go to the URL that will give you a choice and save you money(up to half). You'll be glad you did! Just when you thought you had all this figured out, the gov't changed it:

Do you remember the external video modulator for the old TI 99/4A computer? They had a five pin DIN plug, and ran on +9 VDC. If you removed the resistor in the B+ line (on the circuit board) and jumped it, it worked great on + 5 VDC. The surplus modulators were on the market for years.

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Merry Christmas!

Take care, and God bless.
Michael A. Terrell
Central Florida

On Wed, 24 Dec 2003 20:48:44 -0800, Watson A.Name - "Watt Sun, Dark Remover" Gave us:

Jeez. Ya could have bought one at radio shack for $12.

How nuch is your time worth?

On Wed, 24 Dec 2003 20:48:44 -0800, Watson A.Name - "Watt Sun, Dark Remover" Gave us:

A nine V DC unregulated wall wart probably puts out like 14 peak volts. You are going to shunt all but 5 through a zener?

Watson A.Name - "Watt Sun, Dark Remover" wrote in news: snipped-for-privacy@news.dslextreme.com:

for $4.99 Jameco havs a rf modulator you could wire right inside the dvd I did one for a friend last year it is 12v at 300ma so it sould work just fine for you

On Thu, 25 Dec 2003 18:52:50 GMT, Gunner Gave us:

He's gonna tell us that we're takin' all the fun out of it...

In article , snipped-for-privacy@hotmail.com mentioned...

I'm using a short length of RG-174 50 ohm cable for the video [blush]. But it's nice and flexible, and at that length, less than 3 ft, it's not important. ;-)

I finally solved the problem. See other followup.

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###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
Subject: line with other stuff.  alondra101  hotmail.com
Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

I remember the TI, but the Apple //e freaks I hung around with would have laughed at and derided anyone caught with a TI or a C=64, for that matter. I did have a Commodore +4 that laid in the corner at work for years, then got tossed when we demolished the bldg.

Of all the PCs in the district back then, I heard of, but didn't ever see, that someone actually had a Commodore. There were numerous Trash

80s because we taught on them. And a single, lone Kaypro CP/M system with wordstar. I think the TV studio still has an Amiga.

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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
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Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@

In article , snipped-for-privacy@hotmail.com mentioned...

Modulator works great, it's just that it needed a PS. But I took care of that, see other followup. Thanks.

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@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS?   Check HERE First:###
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My email address is whitelisted.  *All* email sent to it 
goes directly to the trash unless you add NOSPAM in the 
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Don't be ripped off by the big book dealers.  Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com  You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@