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TV stopped playing through RH coach speaker & subwoofer


Jake
 

Intermittent problem here in my 07H.  Sometimes the TV sound only comes out the left-hand coach speaker, meaning the right-hand side speaker and subwoofer (under the fridge) don't work.  But it's only a TV problem--the cab radio plays through the whole system fine.  

Sometimes if I turn everything off again (master TV power switch, move TV/Radio switch to Radio) and turn on again it fixes it, sometimes not.  Sometimes I swear it works fine only if I turn on the TV and speakers while the fridge is in gas mode and cycled on.  Sometimes I swear it works fine only in warmer weather--it just got cold here in Tahoe Forest and the problem returned after not existing the last 4 months of warmth.

When the TV is on and I move the audio switch from TV to Radio mode, I hear an electronic thunk behind or under the fridge.  This leads me to believe there is a gizmo there somewhere to include in my troubleshooting.

Before I begin ripping cabinets apart and chasing wires (or gouging my eyes out trying to trace the wiring diagram on my iPad or laptop since it's impossible to flip between 4 noncontiguous pages at once), I thought I'd post this in case any of y'all experienced this before and know of a magic relay to replace or something.

Thanks in advance for your time!
--
Jake
2007 Navion 23H
Towing 1987 Samurai tintop


old_b4_my_time
 

Intermittent problems like this are hard to trace.   You mention the radio/tv switch, that sometimes moving it makes the dead channel come back alive.   If this is the case you could try 
a) replace the switch and see if that helps
b) obtain a signal tracer (which amounts in reality to a tiny portable amplifier) and leave the switch hanging down until the next occurrence of a failure; then when the failure occurs stick the audio signal tracer probe to see if you happen to have L/R audio signal on both the dual end wires connected to the TV and without flipping the switch, see if the two center wires to the switch have that same dual signal or if one side of it dies within the switch.   If both signals are present on the dual end terminals of the switch and one of the audio signals L/R fails on the center two connections of the swtich, then replace the switch

An audio signal tracer can be made out of a mini-guitar amp, Karoke machine, etc or anything that is a mic or "line level" audio input for some device providing a mini amp function.   To make that sort of device into an audio signal tracer, you would simply find a scrap audio cable and ground the wire mesh wire (shield) to the vehicle frame and use the center conductor of the cable you plug into the mic/guitar/phonograph amp input and this will become your test probe for tracking audio signals.   Then when the failure occurs, simply probe those 4 contacts I mentioned and that would indicate if the break of one side of the audio was occurring inside the DPDT switch.   But this assumes the unit is wired to where these 6 wires are going into the switch.   If there are only a couple of wires on the switch, this indicates that the switch is controlling a remote relay somewhere and that may indeed be what the clunking sound is when you flip the switch and in this case, the relay would need to be probed while the failure was occurring.  Otherwise my memory is foggy if that switch controls a relay with multiple contacts (and thus the clunk sound you hear) or if the signal lines are actually switched with the switch itself.   I'd have to look at the schematic but don't want to get too heavy into helping you if someone else is assisting or you've got it in the shop now being diagnosed, etc.  To mover further  I'd have to download the schematic to see the various options.  

There's just so many things that could cause this, from what I just identified to cold solder joints on the TV circuit board defective from the factory, from  connections that could change with temperature and humidity changes, from corroded plug contacts that go into the back of the TV, or it could be a cracked PC board created and intermittent opening in one of the audio lines..   And while on this topic, I don't know much about your TV setup in that model but if there are audio outputs on the back of the TV, use your signal tracer, mini Karaoke amp or any kind of mini amp if you don't have a signal tracer to connect an audio cable directly to the output jacks on the rear of the TV when you are experiencing the failure and this would tell you if the issue is the TV set itself or the house wiring.   Of course you have to be ready to diagnose then the failure is active.  

If you don't want to lay down the cash for a signal tracer or buy any fancy equipment, you can even buy a $5 USB "audio sound adapter" for your laptop which should have a 3 conductor 1/8" jack for both headphones and microphone and you can e.g. if the audio outputs are RCA on the back of the TV, you can run for example a cable that has on one end a set of RCA component plugs and on the other, a 1/8" three conductor stereo audio plug.  This will feed the audio from the TV directly into the auxiliary USB adapter and you can change the input sources of the laptop and listen over the laptop speakers to see if both sides of the signal are coming through.   

Other issues that come to mind is I know in my 2006 I found a mini amplifier tucked behind a panel and mounted in the mesh of hidden wiring in the above dinette storage overhead compartment.   Now I never traced this out as to the purpose it served but it would logically be serving to convert the audio "line-out level" coming off the TV set, amplifying it and sending that through the switch to the speakers.    I never traced out all the factory wiring and how this functioned because I ripped the stock TV out first thing and put in a DC only TV at the foot of the J-Bed and got rid of the DVD player and used instead an android TV unit (later replaced with Firestick and media server with large hard drive for audio/video entertainment).   So in short, I did an upgrade on the entertainment package first off because what they had was both outdated and didn't match what I was looking for (even though the motorized drop-down TV must have impressed some at the time, as the one they sell today that pops up from a cabinet on the newer models - but then I tend to look at this as potential future failure points  rather than a "gotta have a new one" consumer sucker draw-in).
--
Don - 2006 Navion J


old_b4_my_time
 

Of course do note if the switch I mentioned replacing is controlling the audio line itself (has 6 wires) that would be the point of potential failure or if it is enabling a relay instead (has 2-3 wires) or in other words if it has less than 6 wires then swapping the switch would do not good and the relay would need to be looked at instead as the potential point of failure.
--
Don - 2006 Navion J


David J
 

Yes, the gizmo is a small relay that's in the compartment behind the subwoofer, just loose on the end of its wire bundle. The schematic on an 07H is on page 4 of the "Body 12 volt wiring" diagram.  Take out the subwoofer and you'll find it. Betcha a nickel that it's loose in its socket, or has oxidized contacts on the relay itself.


Jake
 

Thank you both, Don and David!

Don--I really appreciate your instructions and suggestions of hacks, since I don't have a mini amp.  I'd have to go to USB/audio cable route.  Although--I do know how to use my multimeter (usually).  Do you audio cables carry any voltage I could look for?  (Don't stress over answering that--I'll probably test just for the learning experience.)  OOOOOooohhhh I could probably test for continuity from the TV-end of the RCA to the speaker or relay.

This TV is a 12V Jenson LED RV model replaced by the PO when the original TV died.  I assume it's a slightly different because the the sound comes out the 1/8" headphone jack into a 1/8"-to-two-RCA-jacks splitter, and on to the RCA cables that disappear into the overhead cabinet.  I'm assuming the original TV had RCA out jacks, and this one didn't so the PO inserted the headphone splitter.  

I know it's not the TV because if I reverse the RCA cables between Left and Right output jacks, the same I still just have a working left speaker and a silent right speaker & sub.  I'm betting it's not the RV/Radio switch because I get the same relay-energizing-thunk (or de-energizing thunk?) when I flip the switch, regardless of whether the problem is present or not.

David J--Thank you for sharing that!  Yeah looks like Sheet 4 and maybe 5 are relevant.  But first I'll try the simple route and look at that relay.  If that's it, I'll happily mail you a nickel!  

I do think it's temperature related.  It's warmed up a bit here in Tahoe Forest (I'm workamping) this past weekend and this week I have electric hookup, so I've been running the electric heater.  Point is, it's warmer inside and out, and the problem has gone dormant for a bit.  I bet when it cools down next week it returns, and then I'll be motivated to troubleshoot.  

Thanks again; y'all are awesome.

Jake
--
Jake
2007 Navion 23H
Towing 1987 Samurai tintop


old_b4_my_time
 

How hard is it to reach that relay?  You might with the TV sound on, grab the bundle of wires attached to the relay, holding it like a horse tail and slightly move the bundle around a little while holding the relay steady in the other hand (if it is not anchored) and see if you hear any cracking or loss of sound in that intermittent channel.   You might also tap on the relay case with a screwdriver handle to see if that makes the failure re-appear.   If the relay is plugged into a connector that the wires are connected to, you might remove the relay and clean the contacts while noting if you see any corrosion.
--
Don - 2006 Navion J