Any Factory Radio Experts?

Hi all, since my current radio in my 240 (TD-603 with an amplifier) is starting to randomly cut out despite changing all the major capacitors, I recently treat myself to an older and more upmarket CR-4024 radio with a HA-4020 amplifier. It was bought from a car that is being stripped for racing and I'm told it turns on and displays but he's unable to test the sound and cassette deck. Still, I like being optimistic!

First problem is I plan to play cassettes on it so I want to remove the cassette deck to give it a clean and replace the belt which is probably stretched by now. On my old TD-603 removing the cassette deck was easy, 4 accessible screws and the whole mechanism pulled out but looking at this one I have no idea where to even start (see picture)

Next I'm not sure what all the buttons do on the radio itself, I have identified most of them but I need some help with a few.

Thirdly I need help identifying what each cable coming out of the amplifier and radio are for. There is a wire coming out of the radio with the 9 pin square connector used for connecting the radio harness with the amplifier to the car although it's looking like the radio has a small amplifier built in meaning you can bypass the amplifier if you have 2 standard speakers in the front like I have. The amplifier also has a 9 pin male connector and attached to it is a 9 pin female connector which I'm guessing would connect to the male connector on the radio.

My theory is you would only use the amplifier if you have speakers in the back or you have upgraded to bigger speakers. I don't know if this is right or not. See Images

Thanks
Peter

Somehow it didn't embed the images.

Here are the links:
https://ibb.co/fFMgQG
https://ibb.co/mwEPeb
https://ibb.co/j9b4eb
https://ibb.co/dQPwsw
https://ibb.co/cA5QkG
https://ibb.co/hHBLKb
https://ibb.co/dDWy5G
https://ibb.co/kQvEeb

The amplifier runs all the speakers. You should be able to find a wiring diagram to let you know what the exact wires are. The flat connector from the back of the radio contains the power wiring, power antenna if you have one, and a few other wires. On my 93 the circular connector is the audio connection to the amp. The amp has another flat connector coming out of it that runs to the speakers.

If you’re wanting to use an aftermarket radio, bypassing the amp is necessary. If you’re wanting to use the factory amp, you’ll probably also need the radio wiring harness from the vehicle you took it from. Don’t really have too much more info than that. But good luck!

The CR-4024 is the UK version of the CR-4123 used on north american cars. "LO" is the Local/DX tuning mode switch. If you don't see four screws to remove the bezel from the radio, you may need to remove the knobs, then remove the nuts holding the face to the radio. At that point, you'd be able to remove the top and bottom covers to gain access to the internals.

The other DIN plugs shown go to the EQ-2110 graphic equalizer that would go in the bottom location by the shifter. To use that, you'll need to replace the short pocket with the older style pocket that's about 8 inches deep. It does fit, btw.

Another option, instead of using the stock radio and amp setup you have, pick up a late '80s or early '90s Sony, Kenwood, Alpine, Pioneer, etc, tape deck and install that at the bottom of the dash. It'll look period correct, have a better tape mechanism with at least Dolby B noise reduction, and will likely have 25 watts per channel, which is more than what the 4020 amp provides. A lot of them have the ability to control a CD changer, too, without being blingy like more modern decks.

To fill the hole above the vents, pick up a GLT gauge cluster. Voltmeter, oil pressure, and ambient temperature. Add a matte tachometer in place of the large clock, and a small 52mm clock from a 1981-82 240GLE or GLT with the adjustment knob that you depress to adjust the time.

Hi thanks for the reply, I did manage to get to the belts in the cassette deck and it did indeed involve removing the knobs and front face, then you had to remove the entire bottom circuit board.

To me it looks like this radio has a small amp built in and is capable of running the 2 front speakers but you will need to connect it to the actual amp if you want to run 4.

I'm still a bit confused what the single yellow wire coming from the radio is for, it has a fuse in the line and a spade connector. The man I bought the radio off said the spade connector connects straight onto the fusebox but there is already power going to the radio from the 9 pin connector, I'll just have to plug it in when it's ready and see.

When I had a CR-712 (newer version of the same deck), I seem to remember that the extra wire was for illumination purposes.

Yes, the CR-4024, 4123, 7123, and 712 all have a 2-channel amp in them. You could run the front speakers off of that, then use the 4020 for rear speakers. Just would need to modify the internal wiring on it to tie the front and rear channels together, so it doesn't get the preamp signal when the fader is set to the front speakers. So, theoretically, you could then have a six speaker system in your 240, not unlike the late model 700 series cars and the 900 series cars. Or, try bridging the amp for more power to the rears.