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[Kevin Wood]

The CCR2006 stereo as fitted to many Omegas at the factory is quite a nice unit in many respects. The 4 CD changer is handy, the radio works nicely and it has nice integration with the MID to update the clock to RDS time. The steering wheel controls are very useful and it has decent support for connecting mobile phone car kits.

Unfortunately, whilst it sounds reasonable at low volumes I find that the power output is not quite good enough for  enthusiatic listening, especially at motorway speeds. In addition, the sound gets pretty harsh even at modest listening levels.

As with many car head units, the CCR2006 is let down by its' power amplifiers. Packing four channels of audio amplification into a DIN size case forces many compromises (although double din, the CCR2006 is built as two separate single DIN units, a radio/cassette and a CD changer bolted together). There is insufficient space for anything other than a couple of small chips to form the power amplifier, the unit is physically too small to dissipate the heat that is generated by more powerful amplifiers and, constrained by a supply voltage  of only 12-14 volts, the power output is limited to a theoretical maximum of 18 watts RMS per channel into 4 ohms with a bridged amplifier.

The solution to the power amplification issue is to use a good quality external power amplifier, of course. Less constrained by space, these have large heatsinks and good quality amplifiers, and have the space for additional power supply circuitry to step up the car battery voltage to a higher voltage, making much higher power levels possible. They also allow the head unit to run cooler.

Ideally amplifiers should be driven from "Line Level" outputs from the head unit, as this bypasses any deficiencies in the power output stage of the head unit. Unfortunately the CCR2006 doesn't have any line outputs available. Whilst it is possible to drive some amps directly from a speaker output, I was concerned that the CCR2006 power amplifiers would still degrade the sound and the amplifier I purchased on EBay didn't have speaker level inputs.

Some would say that a new head unit would be the best choice, and, indeed, it probably is the easiest option. However, there's a limit to how much I was prepared to spend for a line output and I like the way the CCR2006 integrates with the rest of the car and, most importantly, doesn't look anything special to the passer-by. Take away the nasty internal power amplifier and the performance of any CD player / Radio is adequate in a car environment as it's not exactly an environment suited to critical listening.

The following procedure describes how to fit Line Level outputs to the CCR2006. Note that it does require some dismantling of the unit and soldering small components. It should only be attempted by someone who is competent at working inside electronic devices.

[Kevin Wood]

Items required:

Set of small torx screwdrivers
Small wire cutters and strippers
Long nose pliers
Small flat bladed screwdriver
Allen keys
Double DIN removal tool
Fine tipped soldering iron and solder
One small capacitor to block DC on each signal line to be provided (1 to 22 uf, 16v)
Length of miniature screened audio cable
Connectors of choice for output cable (female phono line socket)

The procedure is as follows:

1) Disable code protection on the unit (optional).

I found it convenient to disable code protection on the CCR2006 before starting work. This is because I knew the unit would be in and out of the car a couple of times during the procedure and because I wanted to test it on the bench (without the MID connected!) once modified. I suspected that entering the code without a MID would not be easy.

The code can be disabled by powering up the unit with AS held down until a beep is heard, then using buttons 1,2,3 and 4 to change each of the digits displayed until the displayed code matches that on the car pass. Finally, AS should be held down once more until a beep is heard.

Removal of the code can be verified by powering up the radio and checking that "CODE" does not appear on the MID.

2) Remove the CCR2006 from the car.

The CCR2006 is secured with the usual arrangement of a cage in the car into which the head unit clips. A double DIN removal tool is required to release the clips and allow the head unit to be removed. Before this may be used, however, a small allen key should be used to unscrew the small grub screws that cover the four removal tool holes in the fascia of the CCR2006.

With the screws removed, insert the removal tools until they are felt to engage with the clips on the CCR2006 then withdraw the CCR2006. It may be too tight a fit to pull the CCR2006 out using the tools alone. In this case, it may be possible to ease it out by carefully placing a finger and thumb in the cassette and CD changer openings, being careful not to pull on the plastic fascia, but the more substantial frame of the radio behind it.

Double DIN removal tools are available from Halfords for the Vauxhall radios. If a tool is not available it is possible that one could make do by inserting drill bits or allen keys of appropriate diameter but with a greater risk of damaging the clips on the radio chassis.

3) Remove the top cover

The CCR2006 has the appearance of two single DIN boxes bolted together. The upper box contains the radio, cassette and power amplififers whilst the bottom box contains the CD changer. We require to remove the top cover from the upper box only.

The top cover is secured only by metal tags around the edge of the cover. These engage in grooves in the side casing and the cover can be eased loose of the side casing by working round the cover and levering it up using a flat bladed screwdriver.

Put the top cover aside once it has been removed.

4) Remove the cassette mechanism

The cassette player mechanism sits on top of the part of the main circuit board which we need to access so unfortunately it must be removed. It is located by four torx headed screws and connects to the main PCB via two multi way connectors.

The following picture shows the approximate location of the screws and connectors:



Gently prise away from the main board the connector with multi-coloured ribbon cable located just in front of the cassette motor. There is a second connector on the opposite side of the cassette mechanism adjacent to the head. This has a brown paxolin extension which should be gently eased upwards to release it from the main circuit board.

The four screws which must be removed are at the four corners of the mechanism as pictured.

Once unscrewed, it is helpful to pull forward the rewind and fast forward buttons on the fascia while simultaneously lifting the rear of the cassette mechanism and withdrawing it from the chassis.

Put the cassette mechanism aside somewhere safe (wouldn't it be awful if that stopped working!).

5) Identify the Gain / Tone control IC.

Having removed the cassette mechanism the IC of interest can be seen. It is located right beneath where the cassette motor was located before the mechanism was removed. It is in a 28 pin package bearing the part number TDA7313N.



The function of this IC is to select the correct audio signal from the CD, cassette, Tuner or external car kit, apply a variable gain to the signal to allow the volume level to be adjusted, filter the signal as required by the settings of the bass and treble controls, split the two channel signal into front an rear pair and to adjust their individual volumes based on the balance and fader control positions. In short, this IC does most of the processing of the analogue audio signal in the CCR2006. The four analogue outputs from this IC are the line level feeds to the internal power amplifiers and it is these we need to connect to in order to bring out an external line level signal. The pin assignments for these signals is as follows:

Left Front      Pin 25
Right Front      Pin 24
Left Rear      Pin 23
Right Rear      Pin 22

Pin locations are as shown in the following picture:



It is possible to bring out all 4 of these signals although I chose to connect just the front pair. I figured that I would either use the internal amplifier for the rear door speakers or, in the event that I decided to connect them to the external amplifier, do away with the fader control for simplicity.

[Kevin Wood]

6) Add DC blocking capacitors to the pins required

Once you have decided which signals to take out as line outputs, it is necessary to add a DC blocking capacitor in each case. This is because the signal outputs have a DC offset which could cause problems for amplifiers further down the chain. I used 4.7uf electrolytic capacitors that happened to be in my junk box at the time. The value and voltage rating are not critical. I would suggest any value between 1 and 22 uf with a voltage rating of 16 v or more.

If using electrolytic capacitors, ensure that the + (positive) lead is connected to the TDA7313.

Solder the positive lead of each capacitor to the appropriate pin, bearing in mind that the cassette mechanism motor will be mounted above the chip and that there is not very much clearance. The following picture shows my capacitors in place. This positioning worked OK clearance wise.



7) Connect screened audio cable to the capacitors

Screened twin audio cable should be used to take the outputs from the unit, terminating in a connector of choice (a female phono jack for each channel is suggested) The ground braid of the cable needs to be connected to an audio ground and it so happens there is a reasonably large area of copper connected to audio ground on the other side of the chip, connected to pin 3. This is visible on the top right side of the chip in the above picture. Scrape away the green protective film from part of this area, tin it with solder and solder the braid of both conductors to the ground area, ensuring that no whiskers of braid are left as these could short to adjacent areas of the board.

The inners of the screened cable can now be soldered to the negative pin of each capacitor as shown in the following picture:



The cable can be routed out of the unit through the small gap next to the ISO connectors on the rear panel. There is a gap under the ISO connectors in the vehicle mounted frame through which the cable can pass if care is used in reinstalling the radio.

Have a thorough check for any fragments of wire or solder and any shorted pins on the chip before proceeding further. Avoid leaving anything loose inside the unit as this could jam in the mechanism at a later date. It may be worth securing the capacitors and cables in position with glue or silicone sealant however I felt mine were secure enough without.

Replace the cassette mechanism.

Reinstallation of the cassette mechanism is the reversal of the removal procedure bearing in mind the following points ;-) (where have I heard that before?)

Ensure that the cassette motor, spindle and belt do not foul on any of the new components.

9) Testing (optional)

I tested my unit out of the car using a spare ISO connector to supply power to the CCR2006 from a bench power supply. I soldered a phono connector onto each channel's output and plugged this into a Hi-Fi amplifier's CD input. Start with the amplifier's volume turned down low to protect the speakers! It's tricky driving the unit without the MID connected but you should be able to insert the CD caddy and wait for it to begin playing. Once music is heard check for loose connections and that the balance and fader controls affect the signal as expected. Check the quality of playback is as expected. It's worth playing a tape (if you still have such things!) to verify that the tape player is correctly installed and that the motor pulley / belt doesn't foul on anything.



.. and that's about it! Connect the line outputs to your amplifier in the normal way and enjoy!


Kevin

[x25xe]

VERY nice guide there mate!  The only thing I would add, if I may, is a general warning about not heating the chip up too much with the soldering iron.  Although, having said that, I suspect that only people who are used to working inside such equipment would give it a go.  I would also have got some small heat shrink and placed this over the legs of the capacitors - however, they are not likely to move much I suppose.

Get one on the admins to sticky this at the top or something - it would be a shame for this to move further down the board and not be noticed!

[Kevin Wood]

Yep. Fair point about insulating it with some sleeving. It I'd had some to hand when I had it all apart I would have done the same however it all ended up pretty rigid so it's not going anywhere. Depends how stiff your screened cable is, as that tends to anchor everything down.

TheBoy offered to move this to the how2 section. Guess he's away from the forum at the moment.

Kevin