[ericrob]

Hi ,i Have Just Fitted A Rover Cd/mp3 Head Unit In My Rover 75(2001) With A Bmw Loom,ihave Added A Bmw To Iso Harness Adapter And The Unit Made By Iovox Is Working Fine ,but The Radio Station Memory Keeps Defaulting After More Than A Short Period With Ignition Off.can Anyone Help Solve This Irritating Problem.thanks

 

[MikeM]

iirc the problem is that the unit is an Iovox. These were relatively low spec Eastern European units introduced by MGR as another cost cutting measure.

MGR discontinued them smartish because they were inundated with warranty claims due to vast numbers being faulty. imo this is why so many now appear on ebay as there must be big stocks of the ones that MGR stopped fitting to their cars.

Failure to retain the memory was one of the common Iovox faults. I never heard of a cure as most people got rid or replaced with a Sony or VDO under warranty.

hth

Mike

 

[John Hurst]

This CHEAP fix worked for me

I have altered the wiring on the feeds to the head unit, so that it is powered continuously. So far, it has not lost its settings! This could be a cheap fix for any owner who does not want to go through the drama of a replacement head unit/cd changer. It introduces the requirement to manually turn off the radio – not a big deal in my view, and some may consider it an improvement.

I cut the two feed wires a few centimetres from the head unit itself, inserted a 6 amp diode on each, then connected the two feeds together on the radio side of the diodes:

Diodes



Un-switched Feed O--------->|-o------------O to Head Unit (Purple/Pink)

|
| (Link the two on H/U side of diodes)
|



​

Switched Feed O------------>|-o------------O to Head Unit (Light Green/White)


I suspect that this is over complicated. I did it this way to ensure the total current used by the radio was spread between the two fuses that currently supply it. The diodes are to prevent any crossover between the two feeds. It could be argued that only one diode is required, on the switched feed, to prevent the un-switched feed powering ‘backwards’ up the switched feed.

However, given that the un-switched feed has a 15 amp fuse, I suspect that the un-switched feed is well capable of providing all the current needed. In which case, the fix is simply cutting the Light Green/White wire, and connecting the head unit end of it to the Purple/Pink feed.

 

[ericrob]

Thanks John My Mates An Electrical Engineer And Maybe He Will Be Able To Do This For Me.it Is Really Irritating As It Stands So I'm Grateful For Your Advice,cheers.

 

[smiddlewood]

you dont need the diodes.

just chop and bullet connect the two power supply leads, (constant live feed and ignition live feed) and then connect them to your constant live feed

the constant live feed will be the yellow wire on the bmw iso loom which sits in the same plug as the red power and black earth.

yellow = live power(small amount of current drawn from the battery at all times, saving settings, radio stations cd position etc.)

red = swtched live power (power signal for the stereo, so it is only on when the battery isbeing charged, obviously only when the car is running tho)

 

[Raykay]

If you just connect the two feeds together, the live feed will be fed back to the ignition switch and you will have a flat battery in no time, the diodes are needed to prevent it.

 

[smiddlewood]

so how come most aftermarket units come with interchangable power leads. i have been retaining and reparing aftermarket head units and sound systems for three years, im not just guessing with my post above.

my advice, get a better head unit! not one that is faulty.

 

[Raykay]

Some systems do need the live feed and ignition feed changed over, not connected together.

If you look at the diagram in post 3, without diodes you can see that power would flow from the unswitched feed, through the link and along the switched feed back to the ignition switch.

 

[smiddlewood]

yes, however surely if the ignition is on,yes it will allow the flow to the HU, wont drain the battery as the alternator will be running anyway, therefore power all of the necessary electronics.

and if the ignition (switched live) is not on, the circuit cannot be completed so there for the battery would not drain.

and yes some systems also require BOTH live feeds to be connected to one source. (unswitched)

have you never got into a car where you can turn the radio on, without the ignition being on. both lives are on the unswitched live.

 

[Raykay]

and if the ignition (switched live) is not on, the circuit cannot be completed so there for the battery would not drain.

Look at the diagram in post 3 again, the switched circuit is connected to the unswitched circuit by the link, the circuit is complete. Hence the need for diodes.

and yes some systems also require BOTH live feeds to be connected to one source. (unswitched)

It's not a problem connecting both cables from the head unit together and to the unswitched feed, it's connecting the feeds from the source together - that will cause the problem.

 

[smiddlewood]

sorry if i was unclear i was not talking about the source feeds in any of my posts. possibly this is where the confusion is happening. i am soley talking abut head unit leads

you would have to be a bit mad to connect both source feeds together, and you would have to over look the blatent obvious that they are seperate for a reason.

so it could just be myself, misunderstanding.

or we could be arguing the same point, but in a very awkward way.

 

[Raykay]

Sorted, all makes sense now.

 

[ericrob]

Thanks Guys Your Help Has Been Gr8.so If I Get This Right I Bullet The Ignition Wire On The Hu Side To The Constant Wire On The Hu And Reconnect The Block???