# Need info on Magnavox Observation Camera

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#### flinx

##### New Member
I have aquired 2 Magnavox Observation Cameras they receive power and output video through a single coax cable. I need to find out if there is a way to seperate the 2 so I can put power through 1 set of wires and get video out through the coax. I received some vague instructions on how to do this which resulted in letting the smoke out of one of them (she don' work no mo).

Instuctions as follows:

" I am not familiar with the particular camera you have. However, these all work the same way.
The DC power was sent up the coax and the video is AC coupled and sent back down. If you open the
camera and trace the wire from the center pin of the UHF connector, it will lead to an inductor
and a large value capacitor. The video is coupled through the capacitor, which blocked the DC
power from the video output amp. The inductor (coil) blocks the video from getting back into the
power section.
Cut the inductor loose from the center wire of the connector. Put well filtered +12 VDC at 500
mA (1/2 amp) or greater into the inductor at this point while running a video cable from the jack
to a video monitor or to the video input of your home VCR. Then you can see the video on your TV.
Power return is to the ground of the connector or any other convenient grounding node.
If this is helpful, let me know. You did not mention your skill level, so I spoke as to another
engineer. I did get an enquirey about this same thing recently and that fellow was able to make
his camera run using the described method."

unfortunatly the curcuit board is packed and hard to trace. The model # is MC3511 AL01. I can scan the curcuit boards if needed or if someone has access to the original curcuit diagrams that would help too.

#### Sebi

##### Active Member
I've problem with my poor english, please clarify: the 2 cameras uses one common coaxial cable, or separated coaxial cable?

#### flinx

##### New Member
Each Camera Has 1 connector on the back which is supposed to go to a monitor. The monitor Supplies power to the camera through the Coax cable and receives video through the same cable. the monitor would have 4 connectors for 4 cameras. I do not have the monitor.

#### flinx

##### New Member
One more thing they are older camera and have a vidicon type tube instead of a ccd or cmos pickup.

#### pvanderbush

##### New Member
Powered cameras

If you decide not to mess with those cameras, I would be interested in purchasing them. Just give me your asking price. Thank You

#### Nigel Goodwin

##### Super Moderator
I suggest you try checking the date on the posts, almost six years ago!.

#### pvanderbush

##### New Member
Anyone know of Magnavox Observation Cameras for sale? I need the type that are powered by the monitor for a MC3511 AL02 system. (Mentioned in (FLINX) message dated July of 2003) above. Thank You

#### outonbail

##### New Member
pvanderbush, I just purchased one of these cameras new in the box, with paperwork from a local thrift store. They also had the monitor which powers these cameras but I didn't buy it because they wanted $65.00 for it and I didn't know at the time that the monitor also powered the signal. I assumed the camera just used a DC power source and put out your basic video and audio signal. So now that I was looking to hook it up, I realize that it receives it's power from the monitor and is putting out an rf signal. This is what brought me back to this site. I did a search looking to find a diagram which shows how I can wire power to the camera and attach it to my VCR or TV. I paid twenty bucks for the camera. I was thinking about buying the monitor but they wanted$65.00 for that, so being the tight wad that I am, I'm still thinking about it. If I want to, I can return the camera for another 5 days for my money back. But if you want the camera, then I can just as easily send it to you as return it to the thrift store. I'm in Riverside Ca. and I can send photos of the camera if you would like.

#### hunternsf

##### New Member
Magnavox Cameras

I have the 4 Magnavox cameras and the monitor to power them, but I don't have the cable to connect them. Does anyone know if there is a special type of connector/adapter that is attached to the ends of the coaxial cable in order to connect the cable to the monitor and to the cameras? The female ports on the back of each camera and on the monitor almost look like a BNC connector would work, but I don't think it is. It's clearly not the standard threaded connector that the cable service providers use to connect your tv, DVR, etc. Hopefully, you can point me in the right direction.

#### Milkbone

##### New Member
Magnavox Observation Camera MC3511

Used Search engine and found this site. And found myself in same setting.

I have 2 of these camera's and the wire but no monitor. I have formal training in electronics so I know there is a way to seperate the power and video I just havent analyzed it. Found a post by flinx about removing inductor at center pin junction (I assume at that point it removes power from camera which is supplied by monitor) then it explained to put a big cap into inductor. This looses me. Do you mean replace the inductor with cap or tie one end of cap to the loose end of inductor and the other to center pin???

Then connect coax from camera to vcr or whatever (monitor) Where does the power come from to operate camera at this point???

Wouldn't it be possible to remove the inductor from the circuit leaving the power unattached to the center pin and use a 12vdc power supply (xformer for wall outlet) to supply the power to the now seperate circuitry?

It seems if that is all the inductor does (keep video out)

Also the cap on the video side (seems it could also be removed since power is no longer present)

Haven't tried anything yet but i was wanting to seperate power and video to use camera with vcr. Just unsure of what amperage or miliamp xformer to use

Maybe I havent fooled with tronix in a while and am totally off the wall with this inquiry/reply

#### optiplex

##### New Member
I also have one of these cameras- live in Puget Sound area (Seattle, WA USA)

Seeing as no one seems to have been able to come up with a simple way to use these with a standard TV
(if you have, let me know!!), I'm willing to sell mine to anyone in the Seattle/Tacoma area who's willing to come
get it! Might as well save myself the frustration of smoking it and just quit while I'm ahead, unless one of you geniuses out there has come up with a simple solution to this problem and can enlighten me!

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#### Dawg56

##### New Member
Does anyone have the cicuit diagram? I want to locate the inductor and add 12 volts there. Could someone show me on a pic?

#### PhredyV

##### New Member
First: Please do not start off with 12 volts. Many tubes require 6.3 volts on the filament, so that's where I would start.
It just seems easier to design around the larger power users (filament and high voltage).
Second: If you connect the 6.3 volts (connect to the coaxial connector) then check around the base of the tube (inside) you should be able to see the glow of the filament (if not, try lowering the ambient light). Then you can raise the voltage or better yet, look for a newer post.
I just acquired mine and have not yet had time to play with it, so that' all I can offer at this time. I hope this helps

#### flinx

##### New Member
Wow, I forgot all about this thread and site. I did get one camera working. I used an inline coaxial DC block that I obtained (I think) from Radio shack. Basically it was like this:

Monitor-------<DC Block>-----DC power supply>--------Camera.

I do not remember the voltage of the power supply. The image produced had so much burn in I could actually tell what it was pointed at. Someones driveway with a car parked in it.

#### summitville

##### Member
Does anyone have the cicuit diagram? I want to locate the inductor and add 12 volts there. Could someone show me on a pic?

Yes, I know this thread is OLD but ...

Yes, I have the Circuit Diagram.
The Center Pin of the VHF connector only goes to two components ...
a) Capacitor #2157 with a value of 1n
b) Coil #5171 with a value of 4.7uh

very odd component numbering system ...
#11xx = imager
#21xx = capacitors
#22xx = capacitors
#31xx = resistors
#32xx= resistors
#51xx = coils
#52xx = coils
#61xx = semiconductors
#62xx = semiconductors

Remove the Coil #5171.
That disconnects the VHF Center Pin from Capacitor #2169 = 12 Volt DC IN
Then apply regulated 12 VOLTS to the other side of where the coil used to be & Cap #2169.
The 12 volts IN is internally re-regulated down to 9 Volts.
I have 3 Cameras + lens, never used, still IN-BOX with schematic.

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