Inverter

[bplotnick1234]

I have a 1998 Coachman Santara. It is a gasoline powered motorhome with the 5.7L Ford engine. When I turn on the coach and chassis buttons they both light up and the motorhome will start and the steps come out. However, I have no power to the interior of the motorhome despite putting two new interstate batteries in it which I hooked up exactly as the old ones were. The motorhome has a MagneTek 900 series converter/battery charger installed in a side compartment. Is this the unit that converts the battery charge from DC to AC to run some of the interior parts (TV, Micro, lights, etc..) from the batteries or is there another part that runs those items? Is the MagneTek the inverter or does it just charge the batteries? I bought this motorhome used in 2002 and the interior used to work on batteries, but no longer does. Is there a fuse or something I am missing? I tried to read the 6 inch thick owners manual, but I can only find limited information on the subject in there. Any help with be useful.

[wa8yxm]

Mandalay Parr wrote:
How about your Battery OFF switch? Do you have one?

He said he turned it on. (I turn on the coach and chassis batteries and both switches light up).

Researching... please stand by...... Found the owner's manual....
Magnetek 900 owner's manual PDF

It appears the 900 is wired in parallel with the battery, and thus, if the batteries are good, You should have 12 volt power to the system.

I would grab a test light and probe for power as follows.

Ground clip on battery negative, probe positive terminal LIGHT GOOD dark, bad batteries.

Move ground clip to the chassis, most any unpainted metal part should do, LIGHT GOOD, dark bad ground (Very common issue)

NOTE: on the battery probe both the post and the lug on the end of the wire. Same with the ground clip.

Now, follow the positive wire to whatever it connects to, Usually this will be a device with TWO terminals.. Probe both (You may need to move the ground clip, always use unpainted metal or known good ground points)

When the light goes dark, the problem is between lIGHT and Dark.

[Gjac]

When you talk about bolts are you talking about the bolts in your DC panel that feeds the 12 v stuff inside the MH?

[bplotnick1234]

Okay, I got the motorhome at the house and found the box that houses the relay/isolators. With the coach and chassis switches both on both solenoids are getting power. I have been able to track down the coach solenoid by turning off the cut off switches one at a time. I noticed that both solenoids or relays have a 5 amp fuse on each side. I checked both of them and they are fine. I noticed that above the relays there is a thin box that has 6 bolts coming out of it with 3 on top and 3 on the bottom. 5 of the 6 bolts are hot. There is one on the bottom right side that has two large gauge red wires coming from it that appear to disappear under the motorhome into no mans land. This bolt shows cold when tested and has no power to it.

I used a wire and quickly jumped this bolt with one of the hot wires and it now works several appliances and lights in the motorhome. Does this mean that the block or I guess they are called buse panels or wiring panels has one bad bolt out of the 6. If so, can I just jump that bolt or move the wires to an empty bolt (2 are empty)? I just don't want to jump that wire and later have a major mess on my hands with melted wiring elsewhere in the motorhome. Has anyone heard of these small wiring panels going bad at just one bolt?

[bplotnick1234]

Okay, got to check on the motor home today. The batteries are running at full power, but I still have no power to the house/coach at all. I am dead at the fuse box. I turned on the generator and everything has power. I hook it up to shore power and everything has power. Now my question is this. When I turn on the battery power switch for the coach and the chassis I hear a clicking noise from up front. I hear a light clicking noise when I turn on the chassis button and a much louder clicking noise when i turn on the coach. I believe that the isolators or relays are in a box attached to the firewall. Before I go killing myself to try and get in there to open this box and check on things, does anyone know if this is the box for the relays? The box has CRV-8 on it. If this is where the relays are can I jump them to test them? Could a bad isolator or relay be the reason that I have no power on just batteries? Do these relays get skipped when hooked to shore power or with the generator on? Thanks for everyones help so far.

[bplotnick1234]

No instruction book ifeather. I think I will try and call MagneTek on Friday and see what they can tell me. I will also look for the solenoids Gjac and the battery switch. I have looked for a battery cut off switch, but I have not seen one, but I will look again. I believe that the solenoids are probably what I hear clicking when I turn on the chassis and coach switches. These beasts have soooo much wiring going everywhere. If MagneTek can not help me over the phone and I can not locate the issue myself, I guess I will head to a CW and have them troubleshoot it. Thankyou for everyone's help and everyone have a great Thanksgiving !!

[lfeather]

bplotnick1234 wrote:
I unhooked the old batteries and hooked up the new ones in the same fashion as they were before, but who knows, I may have made a mistake. When I switch on the two switches (Coach and Chassis) they light up and the steps work and the coach starts. Would these come on if I hooked up the batteries wrong? I recently bought a Cen-Tech multimeter tester, but I have never used one before. It is the 7 function model. Do you know what setting I have to have it on to test the batteries? It is a model 90899. Dang, but it looks complicated. I do have a battery charger and I guess that I could put it on each battery and see if they are fully charged. The charger has a meter on it and should tell me I guess.

One more question Roy B. Do you know if this MagneTek is the converter/inverter for the motorhome?

Does it have an instruction book?

[Gjac]

If you hear the Magnatech humming and read 13.2+ v at your batteries when plugged in, your converter is working. It sounds like either your battery disconnect is off or one of the relays is burnt out. You should have the battery disconnect some where near the house batteries. Also on your firewall in the eng compartment you should have 2 solenoids one for the chassis battery and one for the house batteries.

[Mandalay_Parr]

Instead of going back to CW, Maybe find a local electrical person or a mobile tech.
Jerry

[JimM68]

what is happening is that the coach side of the motorhome is not getting any power unless you are plugged into shore power. In that case, power is being provided by the magnatek.

Your coach batteries are not connected properly, or something in the disconnect relay system is not working right.

It could be the relay itself. The contacts get scummy and don't actully pass any current even though you can here the relay click.

[bplotnick1234]

Thank you for the schematic. I am going to give it a few test on Friday and I will see what happens. Black Friday, maybe that is not a good idea. I might wait until Saturday 🙂 I hope that everyone has a great Thanksgiving !!

[D_E_Bishop]

The following link is the schematic for the 900 series converter. If you are comfortable with checking voltages with your meter do so, if not find a friend or auto electrician that is.

link

Your type of converter is no longer being manufactured. Parallax didn't like the circuit et al.

Good luck with the problem, let us know the problem and solution.

[bplotnick1234]

Mowermech, how is Billings right now. It gets darn cold there this time of year. Thanks to everyone for your input.

[bplotnick1234]

2chiefsrus it is the whole motorhome. Nothing works but the steps and of course the engine starts.

[bplotnick1234]

Well I tested the batteries and they are alive and well. The multimeter was not that difficult to use. When I connect to shore power everything works beautifully and the MagneTek actually makes a humming noise and heats up a bit. This problem has been driving me nuts for the past year and I am just now addressing it so I am guessing that nothing will explode.

I did notice today that when I had the coach and chassis power on the electric steps would work, but nothing else except the motorhome would start and run fine. I went to the power distribution panel and checked the point where the red DC line is hooked in. I got nothing at this point on the panel.

You know, when I turn on the chassis and coach buttons I hear a click from up in front of the coach somewhere. Is this normal? Is there an isolator somewhere in the line that may be bad? The power panel has a 12 volt DC "in" connection so I am assuming that the power there is from the batteries.

Also, does the motorhome always run off the batteries even when hooked to shore power? If it does then it makes sense that when it is plugged in the converter is just keeping the batteries charged as they run the motorhome appliances. It is weird that my bedroom tv has an AC outlet and a DC plug in both.

All of the information has been awesome and I really appreciate it.