stereo help required

I

ians

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Good Morning All
Need some help, On the boat I have a Sony CDX-F7500 Stereo fitted with CD changer. the speakers are 4 x Sony MP61 speakers also 2 speakers in the galley which are normally turned dowon (not sure what make)
The problem is if you have the loud option switched on, or the volume turned up resonbly high the stereo just cuts out as in all the power to the unit and the head unit just switches on and off.
This has got me stumped and Im looking for ideas on what the problem may be.

Any help appreciated

Many thanks


ian
 
might be a thermal cutout operating ie unit is getting too hot. If it recovers after a few minutes without problem then also points to an overheating problem. Try pulling the unit out of it's location to get better airflow around the heatsink (usually on the back) and see if it makes any difference.
 
It could be that the power supply connection is slightly corroded - the new minature amps are quite sensative to power shortages. I had a similar problem in an old landrover which was eventually solved by renewing the power supply cables.
 
Thanks for thaht Nick
Have looked at this, there is quiet decent airflow around the back of the stereo, and the problem does happen just after the stereo has been switched on

This is actually the second stereo, when I bought the boat it had a bit of a naff system in which also cut out but I put this down to it been a very cheap unit with not enough power

Regards


Ian
 
Cable and connections look ok, only thing I thought was its quiet thin wire suppying the power to the stereo.
Not sure if this makes a differance, its next on my list to rewire a new feed to the unit.

Thanks for that

ian
 
Hi Ian
I had / have exactly the same problem with my kenwood stereo and it took me a while to work out what it was. Radio is fine if thats all thats on, as soon as I switch on the 4th cabin light or run water then the stereo flashes on and off. If I switch one of the battery master switches on the problem goes away. I feel there cant be enough power available when more than 4 interior lights are on so it needs one of the batteries on to supplement
 
Chris

That makes sence as problem is worse when travelling with Nav lights on. also is just fine if only using the radio, but start playing CDs and then the problem arises.
Not sure what the fix may be tho, as I have 2 135ah batterys running demestic 12v side .

Any Ideas


ian
 
It sounds like the unit is dawing too much current for the supply. Check the connections and try moving where you have the pos and neg connected to. Maybe to a more substantial supply. Alternatively - keep the volume down.
 
Cheers Kev
Think my next move will be to try a new positive feed to the unit, and take it from there. Like I say the positive feed wire is only very thin which I persume will not help

Ian
 
Hi Ian

how's it hanging up t' Ouse bet the blow up sheep will be getting an airing over Christmas

have a good one

cheers Joe
 
If you upgrade both pos and neg cables , and fit a new in line fuse , wired back to the main bus bars , the problem should clear (don't use the old in line, they don't last forever)
 
If you have access to a multimeter, hook it up to the stero power feed and check the voltage at the unit with it switched off. then switch it on and gradually crank up the volume. The "Loudness" control on those things is basically a bass boost and producing more bass means that the amp draws more current. If your feed cables are undersized, they will cause whats known as Volt Drop. It will be easier to see using an analogue meter as when you get big bass notes, the reading on the meter will fall. If you are regularly dropping down below the 12Volts it could be your problem. Most car stereos are designed to operate when the engine is running and the batteries are charging. This will give a supply voltage at the battery terminals of about 13.8Volts which is Alternator output Voltage. This then follows through the wiring system so you should find that the voltage at the stereo will be at that level too ion the case of a car installation. As other posters have said, upgrading the feed cable imay be the only solution in this case.

Volt drop for info is usually calculated in mV/A/m Millivolts per amp per metre and is dependant upon the resistance of the cable. the bigger the cable, the lower the resistance.

All cables have a tabulated mV/A/m rating and you do the final calc by taking the rating and multiply it by the current carried in amps and the length in metres.

hope this helps ...or maybe its as clear as mud, but either way, it sounds like your feed cable may be an issue along with the voltage at the set.

JH
 
JH
I will try what you suggest at the weekend, I did find a problem with the remote commander connection the other day and have resolved that, also did a five minute speakers swop replacing the speakers ith some direct replacment speakers but direct replacemnets are never the same size so 4 hours later at midnight with speakers fitted it was a bit late to crank it up.

But thank you for the above suggestions and I will give it a try

Regards


ian
 
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