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-   -   Factory camera and MMCS replacement (https://www2.pajeroclub.com.au/forum/showthread.php?t=35309)

nj swb 03-11-13 09:49 PM

Factory camera and MMCS replacement
 
3 Attachment(s)
Yes, it can be done, and it's not that hard - in hindsight, when you know what to do...

I bought my NT second hand (from a fellow forumite) on a Friday - in Brisbane.

On Monday, while driving back to Adelaide, I decided the MMCS had to go. :disappointed[1]:

Ever the opportunist, I bought an ex-demo unit from another fellow forumite, Extnix. Although it came with an aftermarket camera and all required cables, I decided I would prefer to use the factory camera - if possible.

After pulling apart the dash and extricating the old unit, the connectors on the back of the new unit didn't match the connectors on the wiring diagram I found in the on-line Russian service manuals - see here.

https://www2.pajeroclub.com.au/forum...1&d=1575282776

https://www2.pajeroclub.com.au/forum...&d=1575282776l

However, the colour-codes of the wires did match, and the modification can be done without cutting a single factory wire.

My new head unit only used two of three multi-pole connectors. The one that wasn't used looked like this:

https://www2.pajeroclub.com.au/forum...1&d=1575282399

The pink wire to the camera is the positive power supply - on my NT, it was measuring 6.6V when the camera was active.

The video signal was on white and light green wires - with my el-cheapo multi-meter, measuring AC volts, the measurement went from about .09V with the camera off, to about 0.27V with the camera active.

The other two wires (pink-black and black-yellow) have me bamboozled. They both appear to be earths, they always seemed to have the same voltage (measuring both AC and DC), and the camera would work with either earthed. In the end, I simply earthed them both. :dunno[1]:

A reversing signal is on the red wire with a green stripe (although it looked more black to me...) Upstream of the diagram I posted above, it comes from an ignition-switched supply, via a fuse and transmission switch - it's essentially a +12V supply that's only on when the ignition is on, and the transmission is in reverse.

So - the Paj provides a +12V source when reverse is selected, but the camera needs +6.6V. So I bought a 6V regulator (LM7806), wired it up and hooked up the camera - no good. :(

Sleeping on it, I concluded the next step was to up the voltage - Mitsubishi was feeding the camera 6.6V, maybe 6V wasn't enough. I modified the regulator circuit (two extra resistors, but it meant I needed to move everything to a small PCB) and (through trial and error - I was too lazy to look up specs and do the calcs) I produced 7V. (For the record, 3k3R between output and ground terminal, then 120R between ground terminal and vehicle ground.) This worked fine without load, but dropped to 5V under load, which caused the regulator to get very hot. Surprisingly, the camera was working and producing video, but the heat was disturbing. I measured the camera load at about 80mA, which shouldn't stress a regulator rated for 1A. I even considered adding a heatsink, but calculated heat dissipation was well within published specs. :dunno[1]:

After more thought, I decided to stop being lazy, and install a 100uF capacitor on the regulator input, as recommended in Fairchild's data sheet. Worked out how to add it to my cut-down piece of PCB, and gave it a test. All good. Stable 7V, and cool regulator. :beer[1]:

Even the video connection was quick & easy (aka cheap & nasty). I had a damaged RCA cable that I didn't see myself ever using again, so I chopped the yellow lead off, and stripped the end. It's not even coax, but I twisted and tinned the ends, then poked them into the factory sockects on the white ("signal") and green ("shield") wires. By deliberately selecting the reversing camera input on the new headunit, I could see the picture on the camera - a fraction noisier than I remember the MMCS picture, but I'll live with it. :)

The last step was to find a signal to tell the new head unit that the camera was required. Theoretically, the new head unit was supposed to receive an appropriate signal via canbus, but (as Extnix had warned me) this didn't work. I already had +12V on my PCB whenever I wanted the camera, so I added another wire to feed that signal into the head unit. Problem solvered! :beer[1]:

For the record, the factory multi-pole connector comes apart, so individual wires can be removed. Unfortunately, all the wires come loose at once, so I am very pleased that I thought to take multiple photos before I started. Ultimately, I removed the wires I wanted, then simply poked new wires into the individual sockets. Theoretically, I can restore the connector to the factory configuration at any stage - but I really don't know why I bothered. It would be almost as easy to simply poke wires into the relevant parts of the factory socket, and probably more reliable to simply cut the factory harness and solder new wires as required.

Anyway, it's done. I'm using the factory camera with an aftermarket head unit, and didn't cut a single factory wire.

Jenko67 04-11-13 06:49 AM

What a great job...:clap2[1]: Want to come and do one for me.....:dunno[1]:

shrek4 04-11-13 06:02 PM

Oh how I'd live to replace the crappy MMCS of my 2010 NT Exceed!

nj swb 04-11-13 06:16 PM

Quote:

Originally Posted by shrek4 (Post 330877)
Oh how I'd live to replace the crappy MMCS of my 2010 NT Exceed!

I could sell you the crappy MMCS of my 2009 NT Platinum! :lol9[1]:

shrek4 04-11-13 07:20 PM

Quote:

Originally Posted by nj swb (Post 330880)
I could sell you the crappy MMCS of my 2009 NT Platinum! :lol9[1]:

Funny man :clap2[1]:

I'd only be interested if it was in 1000 pieces, an improvement it would be!

eci_thump 03-02-14 03:20 AM

Quote:

Originally Posted by nj swb (Post 330744)
Even the video connection was quick & easy (aka cheap & nasty). I had a damaged RCA cable that I didn't see myself ever using again, so I chopped the yellow lead off, and stripped the end. It's not even coax, but I twisted and tinned the ends, then poked them into the factory sockects on the white ("signal") and green ("shield") wires. By deliberately selecting the reversing camera input on the new headunit, I could see the picture on the camera - a fraction noisier than I remember the MMCS picture, but I'll live with it.

If I understand this part correctly, and please correct me if I'm wrong. Theoretically if I wanted to hook up the existing MM rear camera to a new head unit using a RCA cable, I would strip one end off the RCA cable and separate the wiring into 2 and crimp 2 vampire clips to the ends, then clip those vampire clips onto the green and white cables from the original MMCS harness? The other cables involved in the rear camera keep their existing functions (power, power triggered when in reverse, ground). Obviously the new head unit will have its own reverse trigger.

nj swb 04-02-14 08:55 PM

Quote:

Originally Posted by eci_thump (Post 349700)
If I understand this part correctly, and please correct me if I'm wrong. Theoretically if I wanted to hook up the existing MM rear camera to a new head unit using a RCA cable, I would strip one end off the RCA cable and separate the wiring into 2 and crimp 2 vampire clips to the ends, then clip those vampire clips onto the green and white cables from the original MMCS harness? The other cables involved in the rear camera keep their existing functions (power, power triggered when in reverse, ground).

Not quite right. The factory camera runs off 6.6V, not 12V, and this comes from the MMCS unit. When you remove the MMCS this 6.6V source goes with it; you need to re-create this too.

Also, the factory wiring is incredibly thin; I'm not sure how reliable vampire clips would be. :dunno[1]:

eci_thump 11-02-14 01:20 AM

That makes sense. Im curious to give it a try since the alterative is to stick with MMCS and that isnt happening. Any chance you could point me in the direction of the products i'll need to lower from 12v to 6.6v based on your experience.

Thanks,

Ashley 12-07-15 03:52 PM

Thanks for the info.
I just used it to connect a camera to my nt.
I didn't have a camera but all the wiring was there.

On mine I used the 4th and 5th wire on the top row and the 2nd and 5th in the bottom row.

The 5th wires in top row and bottom row went to the camera signal
The 2nd wire bottom row was 12v on reverse power signal and 4th wire top row was power to the camera.

I bridged the 12v in and the camera power feed wires and also ran this to the radio.

The signal wires change colour at the back.
Pink for power at both ends. White for one signal and the other wire which was light green at the front went to the brown at the back.

Cheers

choppa 30-08-15 10:01 AM

I did the same as you Ashley after buying a cheap camera from fleabay for my NS. I mounted mine in the stock position between the rego plate lights .. just had to cut a square hole in the trim for the camera to poke out of - looks OEM

This info by nj swb was incredibly handy.


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