Practical troubleshooting your RV, 101 #1

[Bob Lawrence]

Thanks, Ernie,
Was thinking about it a little while ago.
Will check ii in the am.
Bob

> Bob, check your plug at the bus end. Mine acted strange at the last
rally. Ernie- 83PT40 in Weatherford, Tex
>
>
>
> In a message dated 12/28/08 18:40:06 Central Standard Time,
bobandarlene@... writes:
> Hi Ralph,
> On our trip here to South Padre Island, we stopped at a campground
in
> Rockport.
> I was working outside with my Dremel plugged in and it bogged down.
I
> heard a pop and I lost all the grounds in the bus and blew 6 surge
> protectors.
> Where do I look?
> Could the ground have melted off at the bus 50 amp inlet?
> Bob Lawrence
> 84 PT36
> South Padre Island, Texas
>
> > Hello everyone;
> >
> > Electrical systems in any venue, to many, is confusing and it
does
> not have
> > to be. With just a few simple rules, one can do a systems check
no
> matter
> > if it is a 12vdc/24vdc or an 110vac system.
> >
> > The words, what? where?, how? and why? come to mind as the very
> basic start
> > to finding a problem with systematic troubleshooting.
> >
> > What? equates to, What is the real problem? (does not mean what
the
> problem
> > appears to be.)
> > Where? equates to the physical location of items along a "path"
in
> a given
> > system.
> > How? equates to how does it or is supposed to work?
> > Why? (remember when Dad used to say "there is no such word as
why."
> The why
> > equates to why did it happen in the first place.
> >
> > It is important to try to learn how a system is designed to work
or
> the
> > right way to say this is "know the sequence of operation." If you
> know how
> > it is supposed to work then you are ready to start trying
> to; "recognize"
> > "localize" and "isolate" a problem.
> >
> > Ok lets pick a simple system; 12vdc fan. Problem, fan does not
run.
> Ok so
> > now we know it is a fan not coming on, so the problem
> is "recognized." So
> > what do we really know about "where it is." A switch on a dash,
the
> fan is
> > located behind a panel near the co pilots feet, but is there more
> in that
> > system besides a switch and fan motor? Could there be a "relay"
in
> line
> > between the switch and fan? Could there be a circuit breaker or
> fuse,
> > between the switch and fan motor? All are valid questions and can
> be
> > answered with a "sequence" of operation.
> >
> > "Sequence" of operation for the system above; 1.it is a 12vdc
> system so
> > from the system circuit breaker, 12vdc is supplied to a switch
and
> from the
> > switch to the coil of a 12vdc relay then 12vdc passes through the
> contacts
> > of the relay to the fan motor and the fan motor runs.
> >
> > Now we know the "how" it works, we can start to "localize" the
> problem.
> > Starting at the circuit break we are going to check for 12vdc to
be
> sure
> > the switch is in fact getting power. Yes voltage is present. Then
> go to the
> > switch and check for 12vdc, yes voltage is present on one side,
> then switch
> > the switch to the run position and check for voltage. It is found
> that
> > 12vdc is present on the out put side of the switch. Next stop is
> the relay
> > coil, check for 12vdc at the coil of the relay, yes 12vdc is
> resent, then
> > check the out put side of the relay, no voltage found, hmmm,
> interesting,
> > now it is time to find out how the relay works, 12vdc goes to the
> coil of
> > the relay then passes through the coil to ground and the relay
> energizes
> > and the contacts are changed in state for open to closed, but the
> 12vdc
> > power source is from some where else going to the 12vdc fan motor
> and not
> > the switch on the dash. Now one must check the voltage patch the
> flow
> > through the relay to the 12vdc fan motor, and find the "why" it
is
> not
> > present. So we have isolated the part of the 12vdc circuit that
is
> not
> > working to turn on the fan with the switch. Checking the "source"
> circuit
> > breaker, it is found not to have 12vdc present. So the circuit
> breaker is
> > the bad part, it must be replaced. Now switch on the dash switch
> and the
> > fan motor runs. Great! you have fixed the problem, or have you?
Did
> we look
> > into the "why" the circuit breaker went bad? This part of trouble
> shooting
> > is not always well defined and in fact may not be found. So that
> brings up
> > the question, what must happen to make a circuit breaker fail?
Lose
> > connections are a cause. Bad ground is a cause, age of the part
> will
> > contribute to the cause of failure.
> >
> > As you can see there can be several steps and items in a system
> even one as
> > simple as this one. Trouble shooting can be VERY time consuming,
> but it has
> > to be done to make a system work. Once you have been through a
few
> > troubleshooting procedures like this, you learn some short cuts
> here and
> > there that helps to "cut" the time factor down a bit.
> >
> > Also a thing to remember. Nothing is set in concrete when trying
to
> find
> > out and repair what does not work. What I am trying to do here is
> show a
> > process that is practical, saves time and effort and cuts the
cost
> of a repair.
> >
> > Let's not throw money at something in hopes that is will make it
> run. You
> > can sure go through allot of money doing that and still not find
> the
> > problem let alone fix it. So with a few trouble shooting steps we
> have
> > spent $3.00 on a part to make the system run, instead of spending
> $225.00
> > in parts like new switch? new fan motor, new relay and so forth.
> Yes it has
> > cost the time to troubleshoot the system but is still cheaper on
a
> repair
> > bill than throwing money at some thing.
> >
> > Will stop here for this first post and wait a few days and answer
> any
> > questions anyone may have.
> >
> > Ues I know it is a VERY simple system noted above, but there are
a
> large
> > percentage of people that do not have any idea what or how.
Please
> keep
> > that in mind when posting on this first post.
> >
> > Safe travels,
> >
> > Ralph and Charolette Fullenwider
> > 84FC35 "Ruff Diamond"
> > Duncan, Oklahoma
> >
>