I have a 1995 Omega Elite. It had no radio when I got it but did have a
Philips changer in the boot.
I  bought a JVC MP3 radio CD and got the appropriate adaptor from Halfords.
The original plug has two familiar iso connectors plus a longer third plug
which I am told sends info to the the computer display and also operates the
changer.

Plugged in switched on but sound is just audable at top volume although
ballance and fade controls work fine.
I have metered the speaker cables and get  0 ohms readings all round.

I have cut the adaptor cables and put in bullets so I can play around . At
one point I had all speakers working Ok but by connecting just one wire of
each of the 4 pairs !!
This was fine until I switched off and on again and then I was back to the
low volume again. If I connected the speakers once the unit was switched on
I got proper volume.
I cant even get that to happen now although the radio is working on four
speakers wired directly to the socket.

Help please before I go mad.

paul  wrote:


> I have a 1995 Omega Elite. It had no radio when I got it but did have a
> Philips changer in the boot.
> I  bought a JVC MP3 radio CD and got the appropriate adaptor from Halfords.
> The original plug has two familiar iso connectors plus a longer third plug
> which I am told sends info to the the computer display and also operates the
> changer.
> 
> Plugged in switched on but sound is just audable at top volume although
> ballance and fade controls work fine.
> I have metered the speaker cables and get  0 ohms readings all round.
> 
> I have cut the adaptor cables and put in bullets so I can play around . At
> one point I had all speakers working Ok but by connecting just one wire of
> each of the 4 pairs !!
> This was fine until I switched off and on again and then I was back to the
> low volume again. If I connected the speakers once the unit was switched on
> I got proper volume.
> I cant even get that to happen now although the radio is working on four
> speakers wired directly to the socket.
> 
> Help please before I go mad.


Sounds like it comes with some sort of standard amp. Probably hidden
under the dash somewhere.

If this is the case, you'll need to bypass that and drive the speakers
directly from the head unit.
-- 
Steve H 'You're not a real petrolhead unless you've owned an Alfa Romeo'
http://www.italiancar.co.uk - Honda VFR800 - MZ ETZ300 - Alfa 75 TSpark
Alfa 156 2.0 TSpark Lusso - Passat 1.8 Turbo SE -  COSOC KOTL
BoTAFOT #87 - BoTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #

Thanks for that. I had started to wonder on that one. Apparently this model 
has an automatic volume control connected the road speed. So there must be 
some type of ampbetween the speaker output and speakers hence the lack of 
readings on my meter. Well the ide of getting all door panels of and trying 
to re-route cables does not appeal!. i think I will just try to brealout 2 
speaker outputs and mount speakers on the parcel shelf. Again many thanks 
and any further advice would be appreciated.
"SteveH"  wrote in message 
news:1h1zbr4.1vfka4akmrek0N%steve@italiancar.co.uk...

> paul  wrote:
>
>> I have a 1995 Omega Elite. It had no radio when I got it but did have a
>> Philips changer in the boot.
>> I  bought a JVC MP3 radio CD and got the appropriate adaptor from 
>> Halfords.
>> The original plug has two familiar iso connectors plus a longer third 
>> plug
>> which I am told sends info to the the computer display and also operates 
>> the
>> changer.
>>
>> Plugged in switched on but sound is just audable at top volume although
>> ballance and fade controls work fine.
>> I have metered the speaker cables and get  0 ohms readings all round.
>>
>> I have cut the adaptor cables and put in bullets so I can play around . 
>> At
>> one point I had all speakers working Ok but by connecting just one wire 
>> of
>> each of the 4 pairs !!
>> This was fine until I switched off and on again and then I was back to 
>> the
>> low volume again. If I connected the speakers once the unit was switched 
>> on
>> I got proper volume.
>> I cant even get that to happen now although the radio is working on four
>> speakers wired directly to the socket.
>>
>> Help please before I go mad.
>
> Sounds like it comes with some sort of standard amp. Probably hidden
> under the dash somewhere.
>
> If this is the case, you'll need to bypass that and drive the speakers
> directly from the head unit.
> -- 
> Steve H 'You're not a real petrolhead unless you've owned an Alfa Romeo'
> http://www.italiancar.co.uk - Honda VFR800 - MZ ETZ300 - Alfa 75 TSpark
> Alfa 156 2.0 TSpark Lusso - Passat 1.8 Turbo SE -  COSOC KOTL
> BoTAFOT #87 - BoTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC # 

paul wrote:

> Thanks for that. I had started to wonder on that one. Apparently this
> model has an automatic volume control connected the road speed. So
> there must be some type of ampbetween the speaker output and speakers
> hence the lack of readings on my meter. Well the ide of getting all
> door panels of and trying to re-route cables does not appeal!. i
> think I will just try to brealout 2 speaker outputs and mount
> speakers on the parcel shelf. Again many thanks and any further
> advice would be appreciated.


The radios I've seen with speed related volume control just had a tacho 
input on the ISO connector into the radio, the radio handled the volume 
change.

Zero ohms is correct if you m,easure a speaker resistance with a 
multimeter - they are pure inductive devices, they offer a 'nominal' 4 ohms 
or whatever resistance but only to an AC signal. A DC test voltage from a 
multimeter will see them as a piece of wire.

Does the head unit have separate RCA outputs for an amplifier? It's possible 
it has an option to turn off it's internal amp if you are using an external 
one (which I don't think you have).

Car radio amps usually use a 'bridge' configuration for extra power from the 
low voltage. This means that by randomly connecting speaker wires to each 
other or to ground you can blow the main amplifier(s) inside and kill the 
radio. Be careful with those bullet connectors!

On Sun, 28 Aug 2005 07:13:02 GMT, paul wrote:


>Thanks for that. I had started to wonder on that one. Apparently this model 
>has an automatic volume control connected the road speed. So there must be 
>some type of ampbetween the speaker output and speakers hence the lack of 
>readings on my meter. Well the ide of getting all door panels of and trying 
>to re-route cables does not appeal!. i think I will just try to brealout 2 
>speaker outputs and mount speakers on the parcel shelf. Again many thanks 
>and any further advice would be appreciated.


The speed dependent volume control is done by the radio and some have a
mute facility for when a telephone is in use.

On some models there is a sound processor and two sub-woofers in the
rear in addition to the normal 4 speakers and tweeters. It looks as
though fuse F6 is present if you have this sound processor. A Radio
without the sound processor has 21 wires and with it 18 (including
earth and aerial).

If there is no sound processor the connections are directly to the
speakers. The circuit in the Haynes manual is very hard to read because
it's been reduced so much but it looks as though the telephone mute
lead is a black one.

I don't know if any of this will be of any help but that's just about
all I can read. I don't have a scanner so I can't scan the diagram but
I doubt if it would be readable anyway.

-- 
Regards - Rodney Pont
The from address exists but is mostly dumped,
please send any emails to the address below
e-mail	ngpsm4 (at) infohitsystems (dot) ltd (dot) uk

I am thinking that becaus the car had no radio when I bought it, that there 
had been a big problem somewhere. The phillips Cd stacker is still connected 
in the boot but no head unit. I bet the processor has been blown. As a temp 
measure as I am going off on hols I have routed two speaker cables and 
brought them out at the rear and will connect a couple of speakers so at 
least I will have sound. It was strange that by connecting one output wire 
from the radio to just one speaker wire I was able to get sound properly and 
either pos or neg worked. There must be a processor in line somewhere and 
probably faulty.
If I could work out how to remove the door panels I could wire the speakers 
back to the radio directly but this is the exec model and so has very posh 
panels and probably loads of hidden screws. This is the answer no doubt but 
I have little time to play just now.
Many thanks for all your help on this
"PC Paul"  wrote in message 
news:NCfQe.54082$Il.49048@fe2.news.blueyonder.co.uk...

> paul wrote:
>> Thanks for that. I had started to wonder on that one. Apparently this
>> model has an automatic volume control connected the road speed. So
>> there must be some type of ampbetween the speaker output and speakers
>> hence the lack of readings on my meter. Well the ide of getting all
>> door panels of and trying to re-route cables does not appeal!. i
>> think I will just try to brealout 2 speaker outputs and mount
>> speakers on the parcel shelf. Again many thanks and any further
>> advice would be appreciated.
>
> The radios I've seen with speed related volume control just had a tacho 
> input on the ISO connector into the radio, the radio handled the volume 
> change.
>
> Zero ohms is correct if you m,easure a speaker resistance with a 
> multimeter - they are pure inductive devices, they offer a 'nominal' 4 
> ohms or whatever resistance but only to an AC signal. A DC test voltage 
> from a multimeter will see them as a piece of wire.
>
> Does the head unit have separate RCA outputs for an amplifier? It's 
> possible it has an option to turn off it's internal amp if you are using 
> an external one (which I don't think you have).
>
> Car radio amps usually use a 'bridge' configuration for extra power from 
> the low voltage. This means that by randomly connecting speaker wires to 
> each other or to ground you can blow the main amplifier(s) inside and kill 
> the radio. Be careful with those bullet connectors!
>
> 

> Zero ohms is correct if you m,easure a speaker resistance with a
> multimeter - they are pure inductive devices, they offer a 'nominal' 4 
> ohms or whatever resistance but only to an AC signal. A DC test voltage 
> from a multimeter will see them as a piece of wire.
>


Speakers are not pure inductive devices, they have an impedance
which is part inductive & part resistive.
[Impedance=sqrt(Resistance^2)x(InductiveReactance^2)]

Put a decent meter across any speaker and it will read pretty close
to its stated impedance.

Zero Ohms would indicate a short circuit, which could quite easily,
and very quickly damage the wirelesses output devices.

J. A. Chewer..

On Sun, 28 Aug 2005 07:13:02 GMT, "paul"  wrote:


>Thanks for that. I had started to wonder on that one. Apparently this model 
>has an automatic volume control connected the road speed. So there must be 
>some type of ampbetween the speaker output and speakers hence the lack of 
>readings on my meter. Well the ide of getting all door panels of and trying 
>to re-route cables does not appeal!. i think I will just try to brealout 2 
>speaker outputs and mount speakers on the parcel shelf. Again many thanks 
>and any further advice would be appreciated.


If it does have an additional output amp you should be able to unplug
and bypss this. I haven't bothered to remove the factory radio from my
Omega, but my wife's Toyota Previa had the additional amp (the radio
Toyota fit has no output amp). It's the output amp that fails (it uses
non-standard transistors so is virtually unrepairable and can't be
bought as a replacement part!). I successfully bypassed it - in the
Toyota it lives above the passenger footwell on the bulkhead - so
retaining the original speakers. It just takes a bit of detective work
with a meter.
-- 
Regards,  Chris    (Please take out my car to reply by email)     
----1961 Austin A40 Farina----1966 Triumph Herald Estate---
---1967 Riley Elf---1965 Hillman Minx---1969 Morris Minor--
-1972 Mini Clubman estate--1957 Standard 8--1979 Ford Capri
    ********** Please don't email in HTML! **********

In article , Chris Bolus 
says...

> I successfully bypassed it - in the
> Toyota it lives above the passenger footwell on the bulkhead - so
> retaining the original speakers. It just takes a bit of detective work
> with a meter.
> 

THat's burgerman fooked then. He's still trying to figure out how to 
indicate a negative voltage on the AC range of a multimeter so he can 
prove I'm wrong.


-- 
Conor

The child is grown, the dream is gone.
I have become comfortably numb. - Pink Floyd

"Conor"  wrote in message 
news:MPG.1d7bc881ac7a1eed98a954@news.individual.net...

> In article , Chris Bolus
> says...
>> I successfully bypassed it - in the
>> Toyota it lives above the passenger footwell on the bulkhead - so
>> retaining the original speakers. It just takes a bit of detective work
>> with a meter.
>>
> THat's burgerman fooked then. He's still trying to figure out how to
> indicate a negative voltage on the AC range of a multimeter so he can
> prove I'm wrong.
>
>
> -- 
> Conor
>
> The child is grown, the dream is gone.
> I have become comfortably numb. - Pink Floyd


Some of the high spec (elite) Omegas came with a bose sound system and for 
further info contact the boys on cavweb forums