Poor radio reception

My 1986 GTA still has the original combo stereo, with tape deck & equaliser. it all seems to work but the reception quality is terrible. it crackles & whines. I have run a separate earth to the back of the set, but no improvement. I have also tried connecting a different car aerial, again no improvement.

Its not vital to get it working properly, but it would be nice.

some components, like capacitors, have a limited life, like about 10 years I think. Jersey John will confirm, I am sure he has posted on this subject in the past.

I was wondering about the suppressors. Where are they fitted & what values do the have ? Might be worth replacing them

I think you need to open up the unit and see what you find.

it all seems to work but the reception quality is terrible. it crackles & whines. ................. I have also tried connecting a different car aerial, again no improvement.

When you say "crackles" ..... does it sound like the spark plugs are causing the interference ..... ie, the crackling changes its sound as the Alp accelerates ?
I think I would be checking out the aerial base behind the interior light fitting first ...... it could be that the main fixing nut for the screen of the cable has come loose and not earthing to the inbuilt metal screening of the roof.
Using an external aerial where the screen at the aerial end is not earthed to the car is not a good test.
The other thing to check is that the earth straps on the carpeted engine cover are connected (two of them) to the spades provided. and for the whine ..... check of just replace the suppressor attached to the rear of the alternator.

Thanks John

There is no specific noise, it doesn't get worse with revs etc. The reception is generally very poor & the radio fades completely sometimes.

I didn't realise there is an earth above the mirror / light, so I will check that out.

thanks again

........... The reception is generally very poor & the radio fades completely sometimes.

With that description of your problem, my monies on the aerial.
One note of caution ......... take interior light fuse out before you remove the light fitting as 90% of the metal work under the lens is live 12v, and to remove the fitting, you will find the earth lead under one of the fixing screws which once removed the earth lead is bound to touch a part of the metal work and blow the fuse anyway. According to my manual, the fuse is third from the left ... top row ... 15 amp.