Way way off topic ... video monitor help needed

[xtal_01]

I know this is way of topic but I am hoping someone out there is a hardware / electronics guru and can give me some guidance.

I have an old motor home (1999). It has it's original back up camera system in it ( really this is also the rear view mirror so it is needed for driving ).

The monitor is a Panasonic GP-RV112.

The camera is only fed by one coax cable ... so it carries the video along with the power ( 12 VDC, 200 mA ).

It stopped working.

I know the monitor is getting power, the screen comes up white ( and the on indicator comes on green ).

I checked and I have no power at the camera.

I checked the monitor .... no power at the coax connector ( well my meter says 3 vdc and then it drops to near zero ).

I am looking for two things ...

1) a schematic diagram for the monitor (I have the users guide), so I can try and track down the problem.

2) a replacement monitor suggestion ... this is not as easy as I thought. It must work with the 15 year old camera, must be 12 volts and must feed power to the camera via the coax ( almost all the "cheap" systems I see out there have separate power and video ... I want to try and not run new wires).

I would appreciate any help ... even if it is just pointing me to a web site were someone could help.

Thanks ..... Mike

[TreeTops]

Go to your nearest RV repair facility and ask them. If they are any good, they should have some recommendations for you. But I bet they recommend a new camera.

[xtal_01]

And that is the problem .....

I live in VT, largest city has a population of 42,000!

There is only one RV dealer in the area.

Not at all helpful. They could not even tell me what filter crossed over on my generator ( old # was obsolete ).

I find I have to do the homework at home, find out exactly what I need and then go to them.

Even then they are way overpriced. Last year my furnace died. $950 plus shipping from them, 5 to 7 days to get it. $350 free shipping on the internet, got it in three days.

Thanks ... Mike

[TreeTops]

I just did a Google search on "RV repair in Vermont" and got over 600,000 hits. Start calling them and ask for help in obtaining a decent backup camera.

[xtal_01]

Oh, I agree, there are lots of RV deals. Just not in our area.

I actually did call a few. There answer "buy a new set".

OK easier said then done. Most new camera / monitor sets us power and video wires. Mine feeds power through the coax. It is cold here in VT. I don't want to start pulling new wire through the RV before our trip next month.

I am sure the local RV dealer will install a new unit for me .... at what cost? They were the ones who tried to sell me a new furnace for $1000. I got a new one off the web for $375!

Thanks .... Mike

[usually_quiet]

I guess you already posted in an RV forum and were not satisfied with their suggestions...

I know that Vermonters are encouraged to be thrifty from childhood, but this is a safety issue. Maybe it is best to spend the extra money now and not have to worry about the cost of not getting this problem taken care of in time.

[xtal_01]

The RV's were very helpful.

I actually am taking their advice and not putting in side cameras. They convinced me it was much better putting my money into new side windows.

The rear camera is just such a pain.

There idea of a wireless system was great. I could use the existing coax for power and then I would not have to run new wires.

The problem is, I have contacted three places now on the web asking about the distance their cameras transmit. Funny, even though they advertise 10 to 30 meters ( 30 to 100 ft ), when I ask them if I can try it and send it back if it does not work they start to back peddle.

Now all three say I should hard wire it.

One place did advertise they don't like wireless because it is a safety issue.

I may end up just trying to get 12v off one of my clearance light for now and using the coax for video.

Truly, we just don't have "extra" money right now. We are living in the RV while building a house. We could not afford this trip at all but my wife already paid for the campground and tickets 2 years ago (got it for me as a 50th birthday, knowing how much I loved Disney). We have rescheduled the trip twice. After three years of freezing in an RV while building a house, we need a break.

Anyway, I am sure I will figure it out .... just thought it would have easiest to fix what is there now.

Thanks ..... Mike

[ponens]

If I understand your description correctly, the monitor gets source power from the RV while the camera gets source power from the monitor over the coax. This is a similar to the way that some satellite dish LNBs get power from the satellite receiver.

This means that the monitor must be doing some power regulation and filtering, similar to what an AC/DC wall transformer does. Especially if the current is limited to 200 mA. If I had to guess off the cuff, I'd guess either a failure in this power circuitry in the monitor (either capacitors, diodes, or regulators) or a failure in the connection of the coax connectors. Is the monitor large enough to contain large electrolytic capacitors? If so, can you open it and check for capacitor leaking/buldge?

[Cornucopia]

IIWY, I'd leave it alone until it gets warmer and then get wired cams that DON'T use "power-over-coax", since those aren't as compatible with most aftermarket cams. Wiring 2 wires (vid signal + power) isn't much bigger a deal than wiring power alone (needed for wireless cams), so I wouldn't get wireless.

Scott

[xtal_01]

Your read my mind ( admittedly it is a short story ). Exactly on the power feed ... it is like the amp I use on the antenna. Power is feed via the coax cable.

This monitor must have a 12 volt power supply and a filter to stop the DC from getting to the RF amp.

It is an "old fashion" monitor ( picture tube ) with no IC's in it.

I put a meter on the coax .... no voltage at the camera.

I put a meter on the coax connector on the monitor .... no voltage.

I pulled the cover off the monitor. Nothing obvious. No budging capacitors, no cracked resistors ... all looks normal.

I have a few friends who I know would look at this, do some testing and figure it out in an hour or so ... but they are 800 miles away right now. I watched one of them rebuild the mother board of a pin ball game. The on board battery had corroded a section of the board ... he actually figured out the circuit replicated it. Way beyond what I do.

I tried putting 12v power onto the coax and feed it into my RV RCA input ( isolated with a .1 uf capacitor and put a choke on the power wire ). Nothing.

So either everything is dead ( maybe the monitor spiked and took out the camera ) ... or it still can be a coax problem.

Next nice day, I was going to put 12 volts into the coax and check the voltage outside at the camera.

I know this should not be rocket science but the RV is very well sealed. Even the covers on the wires outside are a pain to pull off. No easy penetrations into the RV.

Thanks .... Mike