Latest Fiasco: DVD Player Video Out to Antenna In

  • Thread starter Watson A.Name - "Watt Sun
  • Start date
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Watson A.Name - "Watt Sun

Guest
I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.


--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
"Watson A.Name - Watt Sun, Dark Remover" wrote:
I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.
Click to expand...
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.


--
Merry Christmas!

Take care, and God bless.
Michael A. Terrell
Central Florida
 
In article <3FEA786D.9B95775B@earthlink.net>,
mike.terrell@earthlink.net mentioned...
"Watson A.Name - Watt Sun, Dark Remover" wrote:

I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.

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.
Click to expand...
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.
:cool:

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.


--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
The voice of "Watson A.Name - "Watt Sun, Dark Remover"" drifted in
on the cyber-winds, from the sea of virtual chaos...

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.
Click to expand...

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.

--
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.

--

Greetings,

Jerry Greenberg GLG Technologies GLG
=========================================
WebPage http://www.zoom-one.com
Electronics http://www.zoom-one.com/electron.htm
=========================================


"Watson A.Name - Watt Sun, Dark Remover" <alondra101@hotmail.com> wrote in
message news:MPG.1a5306852b54239b989a80@news.dslextreme.com...
I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.


--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
"Watson A.Name - Watt Sun, Dark Remover" wrote:
In article <3FEA786D.9B95775B@earthlink.net>,
mike.terrell@earthlink.net mentioned...
"Watson A.Name - Watt Sun, Dark Remover" wrote:

I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.

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.

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.
:cool:

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.
Click to expand...
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.

--
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" <alondra101@hotmail.com> Gave us:

I scrounged a Mitsumi modulator out of a VCR
Click to expand...

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" <alondra101@hotmail.com> Gave us:

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.
Click to expand...

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" <alondra101@hotmail.com> wrote in
news:MPG.1a5306852b54239b989a80@news.dslextreme.com:

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.
Click to expand...
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

www.jameco.com
 
On Thu, 25 Dec 2003 18:52:50 GMT, Gunner <redwitch01@hotmail.com> Gave
us:

Watson A.Name - "Watt Sun, Dark Remover" <alondra101@hotmail.com> wrote in
news:MPG.1a5306852b54239b989a80@news.dslextreme.com:


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.



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

www.jameco.com
Click to expand...

He's gonna tell us that we're takin' all the fun out of it...
 
In article <bsf2ku$sdb$1@news.eusc.inter.net>, jerryg50@hotmail.com
mentioned...
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.
Click to expand...
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.


--

Greetings,

Jerry Greenberg GLG Technologies GLG


"Watson A.Name - Watt Sun, Dark Remover" <alondra101@hotmail.com> wrote in
message news:MPG.1a5306852b54239b989a80@news.dslextreme.com...
I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.
Click to expand...

--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
In article <3FEB0FE8.1A93BDEF@earthlink.net>,
mike.terrell@earthlink.net mentioned...
"Watson A.Name - Watt Sun, Dark Remover" wrote:

In article <3FEA786D.9B95775B@earthlink.net>,
mike.terrell@earthlink.net mentioned...
"Watson A.Name - Watt Sun, Dark Remover" wrote:

I bot a MagnetBox DVD player for $50 after rebate but it and all the
others didn't have a RF modulator, they only have composite output and
the other higher res outputs. So I've been watching DVDs using a
really old Amdek Apple //e color monitor from the '70s, which works
well with composite input. But I wanted to watch them on my TV, so..

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.

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.

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.
:cool:

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.

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.
Click to expand...
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.


--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
In article <Xns945C83076803Fredwitch01mchsicom@204.127.204.17>,
redwitch01@hotmail.com mentioned...
Watson A.Name - "Watt Sun, Dark Remover" <alondra101@hotmail.com> wrote in
news:MPG.1a5306852b54239b989a80@news.dslextreme.com:


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.



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

www.jameco.com
Modulator works great, it's just that it needed a PS. But I took care
Click to expand...
of that, see other followup. Thanks.

--
@@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:###
http://users.pandora.be/educypedia/electronics/databank.htm
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 <at> 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@@
 
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