by Jeremy Schrag
Today, I'm looking at one of the more desirable recent head units Chrysler produced. A few years ago, when they decided to switch from the rounded style head units found in vehicles from the early part of this century to the newest square faced units, they also decided to make them all dependent on the vehicle's computer bus to operate. No CANBUS signal, no radio.
Understandably, this drove people crazy in the early days of these newer head units. You couldn't power them outside the vehicle to do anything but load and unload CDs, so there was no bench testing them. If they had a problem, you had to be in the vehicle to figure out why they were malfunctioning. Some people wanted to modify older cars for these newer, more feature laden head units, and they couldn't do it because of the CANBUS requirement.
If you are one of those people looking to use a newer deck in an older vehicle, I'm here to tell you that there is still hope.
What you're looking at here is a head unit that goes by the sales code RAQ (see the inset). It is one of the first units to appear in the newer style, and to my knowledge is the only such unit that can be operated with no CANBUS signal. That's right... you can operate this unit any place you can find a 12 volt power source. To make it even more desirable, this unit features support for early VES (vehicle entertainment system) as well as a built-in six-disc CD changer that also plays MP3s.
Before we go on, note the screws on either side of the faceplate. These hold the faceplate to the unit - you will need to remove those if you need to get inside the deck. You will need a Torx T-15 for most of the screws, with one or two being T-10 size. In order service the changer module, you will also need a Phillips #0 screwdriver. A Phillips #2 is required to change the cooling fan.
Here's a look at the topside of the unit with the part number. Supplier code 7910 indicates that this unit came from Chrysler's Huntsville Electronics, predating the sale of that division to Siemens.
Though there are no screws up top to worry about, note the black plastic catch on the faceplate near the bottom left. There is a matching one on the underside of the unit. These serve to hold the faceplate in place when the screws are removed.
On the right side of the unit, there are two screws. Indicated in red, these hold the upper changer tray to the side panel and lower tray. They must be removed to take off either the changer tray up top or the bottom cover.
On the left side, there are a number of interesting arrows to talk about. Red indicates the two screws that hold the changer tray to the side panel. Yellow indicates the two Phillips #2 screws that hold the fan mount in place. Blue indicates one of the bottom cover screws. Finally, green shows us the amplifier chip clamp screw.
There are more screws on the back panel, of course. Red indicates the voltage regulator clamp screw. The blue indicated screw holds the antenna connector to the body, and it needs to come out entirely to get the mainboard out. More on that later.
Yellow indicates two of the four screws that hold the CD changer to the upper tray. Don't unscrew them yet - wait until the changer tray comes out first. You don't need to remove them to get the tray out.
For those looking to modify an older vehicle with this deck, you may need some connector information: the big gray connector and antenna connector are both the same style as the round faced decks from the mid 2000s.
Finally, the bottom cover. There is only one screw to talk about here. Indicated in red, it is the final screw holding the bottom cover on.
Now, we'll remove the faceplate. After you remove the four screws and unclip the assembly, you should see this view. The connector arrowed in red is just pressed in. Pull it straight out so the faceplate assembly can come away.
Before we get to the good stuff, I'll show you how to get at the button contacts and front panel illumination bulbs so you can do some servicing there. Red indicates the seven screws that hold the circuit board in. Remove these, and the board just lifts right out. It could not be easier.
The button contacts are all part of one large silicon sheet on this unit - there are no individual button switches like the old days.
The illumination bulbs are a major source of frustration on this unit. They are standard 12 volt 3mm microlamps like those used in older Chrysler decks, but they're installed in surface mount bases that are a real nightmare to solder around. They are not limited to newer Chrysler decks, either. I have seen slightly larger versions of these in the heater controls of 2008 Caravans.
Now, we'll remove the changer and upper tray. Just remove those four screws I showed you earlier, and it comes right up and out like this.
That bundle of brown wires can be unplugged at either end, but be aware that the mainboard side of it has a locking connector. Just push the latch in to unplug it. On the changer side, the connector is friction fit only.
Before we get to the changer, we'll look at the mainboard area first. This is the fan, a VD0412HBGW. Though it's a little tough to find a direct replacement for it, a 40mm high speed unit that runs on 12 volts should suffice as a replacement. This fan is apparently rated at 7000 RPM, so keep that number in mind when shopping for a new one.
Note that the fan connector is a two pin locking type. Press the catch in with your thumb as you pull on it to remove it.
Now, we'll take a look beneath the bottom cover. Most repair jobs on the mainboard can be done with it still in the case. The voltage regulator and amplifier chip are exceptions, however. To replace either of those, the mainboard should come out.
To get the mainboard out, de-solder and bend straight the seven tabs shown in red above. Referring back to my pictures of the side panel, loosen the clamp bolts for the voltage regulator and amp chips. Then, just take hold of the big gray connector and gently lift the mainboard up in the direction of the blue arrow, and out.
Now we have the mainboard out, and we can perform board level repair work a little easier.
A close-up of the amplifier chip used in this deck. This is a four channel unit that is two ohm stable. While the datasheet claims it to be capable of 72 watts into four channels at two ohms, it is unlikely that you would ever see it thanks to the clipping detection features built into it. Instead, I would count on about 20 watts per channel at four ohms or 35 watts per channel at two ohms of clean power. That's about the best you will get from any head unit these days, aftermarket or not, regardless of the numbers being used to market them. There's only so much power one can expect from a small device like this.
Note that on this deck, there was no thermal grease being used to couple the amp chip to the side panel heatsink. This could mean trouble if you go for two ohm operation, and the chip heats up enough to trigger its built in thermal protection. Consider adding some thermal grease if you plan to stress the deck that much.
We're going to have some real fun now and play with the Mitsubishi built CD changer module. I'm going to get a little more involved in this than usual, because on these decks the changer is a high failure rate item. Often, they will go out with your CDs stuck inside, and I want to show you how to get them back.
This particular changer is hopelessly jammed and completely inoperative. There used to be a seller on eBay that offered new changer mechanisms for these decks, but I haven't seen those show up in some time now. So, I will have to see if I can get this unit working on my own.
In order to do anything with the changer, you need to remove it from the upper tray. Remove the four screws indicated in red to do that. Note the blue arrow - this shows you the motor module that drives the main mechanism that operates the laser arm. If yours is jammed, you need to remove this motor assembly if you need to cycle it by hand. That's where your Phillips #0 screwdriver comes in handy. Four very small screws, and out it comes. You need not worry about any parts going out of alignment on this piece... it just drops into place in there. You do have to watch that the gears mesh, but that's about it.
Flipping the module over, I'll show you how to remove the circuit board. See all the red arrows? Those indicate ribbon cables to disconnect. All of these connectors are the locking type. While you're at it, unplug the green connector - friction type. Unscrew all the blue arrowed screws - one is holding on a transistor not shown here, so I'll point it out in the next picture. Next, bend the orange arrowed twist tabs away from the board so you can remove it. Finally, take your soldering iron and de-solder the tabs indicated in black. The slot load motor is located directly under this part of the board and can only be serviced with the board out.
Note that as you remove the board, there is a single microswitch on the bottom. It's just about right under the orange arrow in the bottom center of this picture. As you play with the mechanism, take care to insure that this microswitch can go back in properly. If you care about fixing the mechanism, that is.
The red arrow indicates the transistor I mentioned. Take care not to flex the leads too much when you remove the board.
This picture also provides a reference to you should you decide to tinker with the mechanism some more. Try not to remove this side panel - the slot load mechanism will pop out of alignment if you do.
On the other hand, if you have CDs stuck in the changer, you do have to remove this side panel if you go in through the top. Remove the two red arrowed screws and take the panel off. Note that one is longer than the other, and must go back where it came from.
This is the view after the side comes off. You can see the laser arm in the middle, though it's hard to tell what's what from here. Note the red arrow - this one ribbon cable must be disconnected to take the top off. It joins the platform loading motor assembly to the main circuit board.
To finish removing the top, remove all red arrowed screws. Then, gently work the whole top panel back and forth, up and down, until it comes off and brings your CD collection with it.
This is the top panel and platform loading assembly once it comes out. Depending on the position it was in when the unit jammed, you may have several CDs stuck all the way down against that white post, indicated with a red arrow. If so, twist off and remove that white post. You can do it with either a 9mm allen wrench from this side, or some needle nose pliers from the other side. Refer to the previous picture to see how it's attached to the top panel.
If you want to put this changer back together properly, prepare yourself for a nightmare. Observe the arrows. The red ones indicate three springs that join the upper platform plate to the lower one. All three need to be there. Pay special attention to the plate indicated with the yellow arrows. This fits against tabs in the main body that hold it up and away from the platform trays themselves. This plate absolutely needs to sit on top of those tabs.
To make things worse, the black and white worm gears on either side are just sitting there with nothing to hold them in place. You have to pay special attention to those, so that they don't move and let go of the trays or the upper and lower plates. And you have to do all this while you re-insert the whole deal into the main body, and that is much easier said than done.
Ultimately, I cannot guarantee I have things in proper alignment in this picture. The deck arrived jammed, so I have no frame of reference to go by. Tinker with this changer at your own risk.
That said, I'm still going to get to the bottom of the mystery of why this changer doesn't work. Let's continue.
With the top plate and platform loading assembly out, we can get a good look at the innards of the changer mechanism. Observe the red arrow - it's pointing straight at the laser power adjustment. The laser sled itself is located on a long arm that swings into place once the proper CD is selected.
Here's another look at the insides. Remember that microswitch on the bottom of the control PCB (printed circuit board) I spoke of? That's it there, arrowed in blue. The red arrow shows you the path the laser arm takes as the main loading mechanism works.
Speaking of the main loading mechanism, you can just see a thin but large metal gear under the plate just below that red arrow. That's the heart of the loading mechanism. That gear is responsible for operating the laser arm and kicking forward the slot loading mechanism so that neither get in the way when the platform loader starts moving discs up and down.
That gear is also why this changer isn't working. You see, that metal gear meshes with a plastic one. That plastic one is stripped out. I'll show it to you in a bit.
Another angle on the insides shows you the gears that make the slot loader work. Not only do they allow the rubber roller to drop into place, but they also help move the whole mechanism back and forth to allow CD swapping.
This is the little gear that's responsible for this changer's failure. As you can see, the small ring of teeth have all been chewed up where they contacted the large metal gear. As luck would have it, though, this changer uses not one, but four gears like this. One black, three white. They will all interchange with each other.
That's what I've done, here. I've taken the black and white gears on that one post and switched them. Now, the remaining intact part of the black gear's teeth can mesh with its neighbor better than it could with the metal gear, and the big metal gear gets a new buddy with good teeth to talk to. Note the nylon washer indicated in red - there are a lot of these in here, and you must be careful not to lose them as you take them off. I use a pair of tweezers. There is a metal plate that forms part of the laser arm out of sight below the bottom of the picture. This plate fits under the arm and pin you see just below the gears, and over the post holding the black gear. One of those nylon washers then goes over the post to lock the plate in place. Fair warning - that plate will fight you if you decide to do a gear swap like I did. Be careful not to bend it as you work on it... if that plate gets bent, the laser arm will bind up, the mechanism will jam, and you can kiss another gear's teeth goodbye.
So now that I've gone to all this trouble, the problem's been solved, right? Well... no. Not having a way to compare this mechanism with a working one, I have not been able to align it so that it works again. I can make the main mechanism cycle, and it does it properly now, but the deck still doesn't think it has a CD changer in it. It will take much trial and error to get it working again. Wish me luck - I need it.
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