XM Radio DC Power Adapter

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quonset
Posts: 20
Joined: Wed Nov 14, 2007 5:07 pm

XM Radio DC Power Adapter

Post by quonset »

Has anyone had problems using the Roady2 power adapter in the chassis or house cigarette receptacle?? Voltmeter readings are less than 14.3 with engine running. (I have been told that 12.2-15.8 volts should not cause a problem for the plugged in device. )The fuse blows in the adapter as soon as I plug it in the chassis receptacle with the engine running or in the receptacle by the sink. The same adapter works fine in our car with the same meter reading. My Garmin GPS also works in the chassis receptacle without any problem.

The problem must be in the motor home but I am not sure what to do next?

Russ
1995 BFT
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whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Post by whemme »

Russ,

I also have been using a XM Radio Roady 2 receiver in my Born Free (year 2000 chassis) for the last 3 years. When not using it in my motorhome, I then move it to my 2001 Chevrolet Silverado pickup. I have never blown the fuse in the power plug for the Roady 2 in either vehicle.

One thing I would question is the acceptability of the DC voltage as high as 15.8 VDC that you report. That seems high to me. I would estimate that the highest charge voltage from any vehicle's charging system would be on the order of 14.8 vdc - not 15.8 vdc. The Roady 2 may have an over-voltage protection circuit in it that will cause the fuse to blow with any applied voltage that exceeds 14.8. I assume that your adapter is the same as shown in the photo below.

You make the statement: The same adapter works fine in our car with the same meter reading. Does this mean that your car also puts out 15.8 vdc when the engine is running?

If your Born Free engine alternator charging system is putting out 15.8 vdc, then I would consider this excessive and that would be hard on your chassis battery causing it mostly likely to overheat and cause premature failure.
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Photo of Roady 2 Automotive DC Power Adapter
Photo of Roady 2 Automotive DC Power Adapter
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Last edited by whemme on Sat Jul 05, 2008 11:24 am, edited 1 time in total.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
quonset
Posts: 20
Joined: Wed Nov 14, 2007 5:07 pm

XM Radio DC Power Adapter

Post by quonset »

Bill:
The DC voltage hasn't exceeded 14.4 in either the motor home or in my 1999 Honda CRV with the engine running. I checked again today to be sure.

One bit of information I failed to mention was that the radio worked in the motor home for several hours while driving. It was plugged into a dual outlet adapter(max of 8 amps)with my Garmin. The radio stopped working in the receptacle near the sink with the house battery turned off and motor home connected to shore power. I thought the stoppage could have been due to a surge from the shore power but after replacing the adapter fuse, it didn't work in the chassis receptacle either.

The adapter looks like the one I have. I bought it on line from myradiostore.com.

The problem must be in the motor home as the same adapter powers the radio in the Honda without any problem.

Any idea what to do next???


Russ
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whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Post by whemme »

Russ,

Are you saying that the Roady 2, when plugged into the coach dash DC power receptacle, will work OK without blowing the fuse but when you plug into the DC power receptacle located in your kitchen with the coach battery master switch OFF is the only time when the fuse blows in you Roady power plug?

If you can, do this test. With your coach hooked up to shore line power. Measure the dc voltage at the output of the DC power receptacle located in your kitchen. Do this test both with the coach battery master switch in the ON and OFF positions.

If the voltage with the battery master switch OFF exceeds 14.8 vdc, I suspect your coach's charger/converter (generally a Parallax 7345 unit) is then putting out too high of a voltage when your coach batteries are not connected.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
quonset
Posts: 20
Joined: Wed Nov 14, 2007 5:07 pm

XM Radio DC Power Adapter

Post by quonset »

Bill:

The Roady2 used to work in the dash DC power receptacle but it no longer does.

I won't have access to shore power until next week so will conduct the voltage test as you suggest. The charger/converter could very well be the problem for the receptacle in the kitchen.

The problem still remains with the adapter not working in the dash DC power receptacle. A friend suggested the problem could be a short somewhere. How do you confirm this is true and then, how do you fix the problem??

Russ
User avatar
whemme
Posts: 2110
Joined: Mon Aug 15, 2005 8:05 pm

Post by whemme »

Russ,

Your XM Radio Roady 2 Power Adapter problem is puzzling. But based on your info that the fuse in the power adapter will not blow when plugged into your motorhome's dash plug-in without the motor running nor will it blow when plugged into you motorhome's kitchen plug-in when you are not connected to shoreline power, I will take a wild guess that you have a defective power adapter.

The function of this power adapter is to convert unregulated +12 vdc power into regulated +6.0 vdc to power the Roady 2 XM receiver. I tested my power adapter and with the input voltage varied from +11 to +15 vdc, its output voltage stayed constant at a precise +6.0 vdc.

Based on the assumption that this power adapter has a over-voltage protection circuit in it that will blow the 2-amp fuse if subjected to an over-voltage, I think that something in this over-voltage circuit has changed or been damaged and it may be kicking in now at a lower voltage like around 14.0 vdc or so that will blow the fuse when the voltage gets that high which is normally the case whenever the engine is running or you are connected to shore line power, depending on which power receptacle you are plugged into in your coach.

I really can't think of any possibility of something being wrong or defective in your coach that could cause this problem.

Since a new power adapter is less than $9.00, I would recommend that you purchase a replacement and give that a try. You can buy them online at several sources including the one below that you have used before under XM Power Accessories.

http://www.myradiostore.com

I hope I am not steering you wrong on this problem, but $9.00 is cheap enough to give a new replacement power adapter a try.
Bill Hemme - Spencer, Iowa
E-mail: whemme@earthlink.net
2002 Born Free (Ford E-450 V10) 26' RSB
2016 VW Golf GTI - toad
quonset
Posts: 20
Joined: Wed Nov 14, 2007 5:07 pm

XM DC Power Adapter

Post by quonset »

Bill:
Thank you for your help.

As you suggested, I bought another adapter and it works in the dash receptacle. I only plug it in after the engine is running to prevent any surge problems. I still haven't figured out why the original adapter worked fine in my Saturn but blew its fuse in the MH dash receptacle. At this point , I am happy to have it work when I am driving.

I also bought the ac adapter for use in rear of the MH but I haven't tried it yet.

Russ
1995 BFT
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