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by Jeremy Schrag • This unit appears to have been used by Dodge, Jeep, Chrysler, and Plymouth
More descriptions of the system and how the Infinity I and II differed are at the end of this page.
Back when Chrysler started to first offer the Infinity sound system in select vehicles, there weren't a lot of options open to them for head units. The first of those systems relied on an update to the Ultimate Sound head unit, which had been used since 1985 or so in many upscale Mopars. In 1988, some new models came into being for these fancy new Infinity speakers to play with. No longer would they rely on the old Ultimate Sound design.
Enter the Infinity I and Infinity II. The former, which was also known by the sales code RAN, would be a simple affair using traditional bass and treble controls. It was be available in two versions, one for cars with the Infinity speakers and one for cars without. The latter, however, was another matter entirely. Going by sales code RAY, the Infinity II was the flagship of Chrysler's audio systems. It was yet another update on the Ultimate Sound idea, only this time it would bring all the bells and whistles of the day to the dashboards of Chrysler vehicles.
It is the Infinity II I am taking on today. This is the version with the digital equalizer, offered only between 1988-1990. It is not to be confused with the updated model offered between 1991-1992, which had manual EQ sliders instead of the buttons. A lot of people ask me about this deck in particular, and it remains very popular among people like me who grew up like me during the 80s, when the best toys all had the most buttons.
Looking at the above shot, it's not hard to see why people find these such cool looking decks. Everything is pushbutton controlled but the fader joystick, even the five band equalizer. AM stereo, music search, motorized cassette loading, automatic tape bias, slave CD port... you name it, this deck had it. About the only thing missing is a spectrum analyzer function for the way cool LED lighting in the equalizer.
Unfortunately, this deck is also perhaps one of the most complicated decks you could find in 1988, aftermarket or no. As a result, it is very rare to find one in fully working order in 2011. A lot can and will go wrong with these decks. I will attempt to show you how to get into one to do some basic service work, but be warned - getting inside this deck is not for the faint of heart. The most common problem after all this time is bad solder joints, and the second most common problem is the finicky, persnickety tape deck design. As much as I hate to say it, I have had only limited success with these. They are very hard to fix, particularly when it comes to the tape deck.
This is the top of the deck. Note the placement of the two screws that hold the top on - we will be removing them before long. The label indicates via the supplier code that Mitsubishi is the OEM for the unit. Interestingly enough, there is an actual model number on the label as well - RX-690S.
Here is the bottom of the unit. Red arrows indicate the screws to remove the bottom cover. We will also be removing this before too long. The unit is somewhat modular in construction. Unlike newer Mitsubishi built factory decks, however, the layout on the inside is a fair bit more confusing; as you are about to see.
The back of the deck shows us the slave CD port, antenna jack, and the usual black and gray connectors. While the slave CD port is intended for the formerly very expensive single CD player option Chrysler offered back in the day, you can use it to add an auxiliary input instead. I will now show you how to do it, if I can direct your attention to the inset in the above picture.
The slave CD port is a standard female 8 pin DIN connector. Before I continue, please take note - my instructions only apply to the Infinity I, II, and III decks. While you will find the same connector on the back of later model Chrysler changer control decks, the pinout is not the same. This is because the changer control decks needed to communicate with the changer via a bus protocol - the slave CD player did not.
Adding an auxiliary input to this deck is actually quite easy. I have pointed out the relevant pins with colored arrows above. Purple is a ground pin - use this for both your left and right audio signal ground. Yellow is the trigger that tells the unit to switch to the auxiliary signal... you short this pin to ground to do this. Yes, you can use the purple pin for this function, too, or the sleeve of the connector itself. A simple SPST switch will do the job. Now, all you need to do is connect the positive audio signal wires. Cyan is the left channel, green is the right channel. Presto - you have an auxiliary input.
The remaining pins on the connector are used for power and illumination by the slave CD player. Take care not to wire into any of those pins. Your iPod probably won't enjoy getting 12V coming in through the headphone jack.
Sharp eyes will have spotted the letter "L" (upside down in this photo) inscribed on the side panel in this shot. Make note of this - you will need to know this is the left side panel if you take this deck apart.
The barely visible "R" indicates that this is the right side panel. Now, we will start taking this deck apart. First, we'll remove the face. Take out the bronze bolts indicated in red, and the corresponding ones on the other side. The face is then clipped on... just unclip and pull it off. You should not have to remove the fader knob to do so.
Remove the two screws on top and pull the top cover off. You should see the above scene from an electronics tech's nightmares. You are now starting to see why I tend to recommend against buying these at the salvage yards. You are looking at only the upper circuit board of the deck, and with bad solder joints being the most common problem with these units, you are facing several hours of soldering work to bring them back to 100%. That's assuming the tape deck can be made to work reliably.
The upper PCB and tray must be removed to access the mainboard, or even provide access to the ribbon connector to allow removing the faceplate PCB assembly. There are a ton of connectors to unplug first. Unplug the three at the top of the picture that run to the faceplate PCB. Unplug the two ribbon cables on either side that run down to the tape deck and power module. Unplug the connector for the slave CD connector (gray wires) and move it out of the way. Unplug the ribbon cable running up through the hole next to the big green capacitor. Unplug the little three pin connector way up by the top left ribbon cable. Basically, unplug every connector on the board and make detailed notes of where everything went.
Once you get everything unplugged, remove the screws arrowed in red. Remove the screw on the back bolting the antenna connector to the deck. Then, gently pull the whole deal up and out, moving unplugged wires out of the way as you do so.
Here is the upper PCB assembly removed from the deck. More than likely, you will have some bad solder joints to deal with on this board. This means pulling the board off the metal. To do this, first remove the screws indicated in red.
Now, heat up your soldering iron. See the antenna jack in the lower left corner? Desolder the white wire that runs to it. Make sure you remember to solder it back up again when you put things back together. Now, turn the assembly over.
If you're anything like me, you'll have begun cursing Mitsubishi well before this point. If you're not like me, the blue arrows should take care of your patience real quick. The arrows indicate points where the metal is soldered down to the PCB itself. You must de-solder every single one before you can remove the board for your re-soldering work on the PCB itself. Note that there is a sheet of plastic insulation in there - remember how it is placed.
At this time, I'll now move on to the rest of the deck just to hurry things up a bit.
You may or may not find your hands shaking due to nerves by this point. Yes indeed, there are more connectors to deal with. Some run below to the power module, some run above to the upper PCB, and some run to the faceplate PCB. Right now, we're going to work with the faceplate PCB. Disconnect the ribbon cable arrowed in red.
Yellow arrows point to the screws holding the entire assembly onto the rest of the deck. Remove those, and the whole metal front can unclip and come away. Do this first. There will be two red cables running to the fader area behind the assembly... they can be unplugged, and must be if you want to do anything at all with the rest of the unit.
Though these particular cables will not plug into each others' connectors, it's not a bad idea to make notes on where all these connectors in the deck originally plugged in. This is especially important for the mainboard. It is very easy to lose track of the cabling in this deck.
The white arrows indicate the screws that hold the PCB to the metal. Remove these to service the illumination lamps in the deck, and the bad solder joints often found back there with them.
Blue arrows indicate the illumination lamps. These can be replaced by unwinding the leads of these little 12V "grain of wheat" bulbs from the gray bases, and then removing the blue filters from the bulbs. It is not easy to do, but probably your only option in 2011. Provided you can find the replacement bulbs, that is (editor’s note: a reader suggested Edmund Scientific’s bulbs, at 100 for $40, which might work. We have not tested them. Jeremy wrote, “The problem with replacing these is that one must be sure to grab the correct 3mm 12V bulbs... these types of bulbs come in several different sizes and voltages. Edmund's are probably correct, but they only specify the voltage, and their price is high... it’s probably easier to find these at places that sell model train stuff than an electronics supply store..”) Many late 1980s and most 1990s Chrysler decks used these bulbs.
Remove all bulbs if you plan to do any soldering on this board. The heat from my iron has killed many of these bulbs all by itself.
Before we remove the mainboard for solder work, we have to empty out the cassette side of the deck. Turn it over, remove the bottom cover, and you should see the above scene. The tape deck is held in with four screws, indicated in blue. On the left side, there is a connector joining it to the power module, seen on the far left. Unplug it. Gently lift the deck upwards just a bit - there are two more connectors and a ribbon cable on the other side you must unplug as well.
With that done, remove the tape deck and set it aside. We'll get into that can of worms later.
This is the bay with the deck removed. The blue arrow indicates the connector for the power module, and the yellow arrows indicate everything that plugs in on the other side of the deck. Again... make notes. At this point, that ribbon cable is no longer even connected to anything, as it runs up to the upper PCB. Which... you removed a couple hours ago. It will fall out of the deck entirely once you remove the panel on that side... best to write down where and how it was in there so you don't have to worry about it later.
Before we get to the mainboard, we'll deal with the power module. This is an optional step - these don't have bad solder joints that often, though the relay area (the black rectangular object) can collect them.
Remove the two screws arrowed in blue (one is hiding behind that blue coil). Unbend the twist tab arrowed in green. De-solder the big black ground wire indicated in red. Now, remove the side panel. Note that when you put this back together, the black wire must be routed up overtop of the power module board, else it will interfere with the tape deck loading mechanism.
We're getting closer to removing the power module. Disconnect the blue arrowed connectors. The red arrow indicates another twist tab to unbend.
Now, you should be able to remove the power module, like so. You can leave the ribbon cable connected, as I have done. That way, you'll have one less cable to worry about later on re-assembly.
Now, we'll remove the mainboard tray and mainboard. On the back of the deck, remove all screws indicated in blue. Remove the remaining side panel. Note that the screws under the black and gray connectors hold the amplifier chips to the back panel for heatsinking - remember where those screws belong. Unplug all wires that run from the black and gray connectors, and the slave CD connector, to the mainboard. Again, make notes on where they go.
The whole assembly should now separate from the back panel.
This is the tray and mainboard removed from the unit. All cables you see here can remain connected while you do your soldering work - no sense in confusing yourself any further. At the top of this picture, you can see the four Hitachi HA13121 amplifier chips that power the four speaker outputs.
To gain access to the solder joints, remove the red arrowed screws. Then, heat up your soldering iron and de-solder the blue indicated twist tabs. Un-twist those tabs to release the board.
Now, you can finally re-solder the mainboard. Inspect every single joint and re-solder as needed. I would point out the most common failure spots, but I'm not sure there's room for that many arrows - the bad solder joint issue is that pervasive in these decks. Take your time, go through each PCB, and re-solder any and every joint that even looks at you funny. You cannot be too thorough for this deck, because you won't want to get it this far apart more than once.
Now, we come to the real bear in the woods - the tape deck. Often, you will find these decks to be quite flaky. Sometimes they will playback at double speed. Other times, the loading mechanism will cycle over and over in an endless loop, clicking the whole unit on and off as it does so. Still other times, they will auto-reverse over and over due to faulty reel sensors. Highly complicated decks that they are, they were perhaps a little too complicated for 1988 technology.
Let's start with the easy stuff. The red arrows point at the capstans. Clean them. Clean the orange pinch rollers behind them, too. And the playback head, while you're at it. The blue arrow indicates the tab and switch that sense a cassette that requires metal and chromium dioxide (CRO2) equalization. You may have to clean this switch if the deck is intermittently flashing its "70uS" indicator in the display.
The deck from above. The red arrow points to the switch that triggers the cassette loading mechanism. When you put a tape in, the metal arm moves away from the switch and in turn activates the loading motor. If this arm has any slop in it at all, it will never push hard enough on that switch to turn off the mechanism when there is no tape in it. This is what causes the endless cycling behavior I mentioned earlier. To help with this, there is a small tab where the arm pushes on the switch. Gently bend the tab further toward the switch - this may compensate for any slop in the mechanism enough to stop the endless loading cycle.
The tape deck from behind. You can see just how much is involved from an electronics standpoint to support all the features of this deck. Look for and resolve any bad solder joints you find.
Before we go on, a word about the double speed playback. This is usually caused by the loading mechanism not dropping the cassette all the way down into position. I wish I could tell you how to fix that, but to be honest I have no idea. Working with the loading mechanism in this deck is way beyond the skills of most, to the point I don't bother with it if I have other parts decks around, which I do. I often wonder if this deck was designed by a watchmaker.
To obtain access to the belts for replacement, turn the assembly over and remove the four screws indicated in blue.
Now, you can replace any snapped belts in the deck. I've pointed out various other items of interest. The blue arrow indicates the loading motor. Green indicates the playback motor. Finally, red indicates the reel sensor PCB. These work by detecting infrared light bounced off the reflective spots on the reels below. If these fail, the deck will auto reverse in an endless loop. This is because the deck thinks one or both reels aren't turning.
At last, we come to the end of our journey inside the 1988-1990 Infinity II deck. Do you remember how it goes back together? I hope you kept your notes handy.
Before I move on to work on my Infinity III article, here's a shot of the deck working. Well... sort of working. This particular one, out of a 1990 Imperial, has the double speed playback issue. A far easier and more temporary way to fix it is to just poke a finger into the slot and push down gently on the cassette so it seats properly.
(Press release:) Chrysler Motors for 1988 has broadened the availability of its audiophile Chrysler-Infinity Sound Systems, added a compact disc player and rear seat headphones for selected vehicles, and renewed its two top-of-the -line radios. The Chrysler-Infinity Sound Systems are now available on 18 vehicle nameplates across eight different body types: Chrysler New Yorker, New Yorker Landau, New Yorker Turbo, LeBaron GTS, LeBaron Coupe, and Convertible; Plymouth Voyager and Grand Voyager; Dodge Dynasty, Daytona, Daytona Pacifica, Daytona Shelby Z, Lancer, Lancer ES, Lancer Shelby, Caravan, Grand Caravan. It also is expected to be standard on Chrysler's TC by Maserati.
CHR YSLER-INFINITY I AND II
Chrysler Motors' partnership with the well-known Infinity Systems, Inc. has resulted in audiophile quality sound at an affordable price. Two different systems are a vailable for 1988: The Chrysler-Infinity I and II. Both feature unobstrusive speakers that are individually amplified and "equalized," or tuned, to the exact interior acoustics of each car for accurate sound reproduction throughout the audio spectrum.
The Chrysler-Infinity I Sound System pairs an Infinity Speaker System with a newly redesigned Chrysler radio-cassette player. The radio features an AM stereo/FM stereo receiver with 20 station (10 AM, 10FM) memory, Dynamic Noise Reduction (DNR) to diminish broadcast "hiss" and an clock in the vacuum-fluorescent radio frequency display.
The cassette player now includes a music search feature that automatically seeks the next selection or returns to the start of the present selection, to make it easier to search out a particular piece of prerecorded program material. The cassette player automatically adjusts for normal or "high bias" (chrome or metal) tape, and features Dolby B noise reduction for superior playback of Dolby coded tapes.
Also new, for this 1988 radio, are state-of-the-art controls, which combine the high durability of electronic touch controls with good "feel" for operation by hand with eyes on the road. Special care has been taken to group basic functions so the driver can recognize and operate them without any distraction.
In addition, all nomenclature is on the controls and fully backlit for night time visibility. The radio-cassette unit is also available on selected models with the standard speaker systems.
The top-of-the-line Chrysler-Infinity II Sound System is similar to the I system with a unique all-new radio cassette which includes a 5-band graphic equalizer. The equalizer can be switched off for the true, "flat" response providedby the Infinity speakers, or it can be switched on for individual tailoring of the sound.
Each of the 5 bands controls a specific tone range: bass, upper bass, midrange, upper midrange and treble. Unusually high control of the sound characteristics is provided by the equalizer, for maximum enjoyment of music andvoice from all sources. For example, the equalizer can be adjusted to reduce only the portions of the sound spectrum that compete with the human voice. This permits conversation among occupants in the midst of full volume music. The graphic equalizer controls are attractively lit to indicate equalizer operation.
COMPACT DISC PLAYER
A new Chrysler-designed state-of-the-art compact disc player is offered for the first time in the Chrysler LeBaron coupe and convertible and in the Dodge Daytona. The compact disc player is designed to start automatically on insertion of a compact disc (CD), and it will automatically override operation of the cassette or radio.
It features a programmable memory for selection of specific tracks. A repeat feature allows the replay of either an entire CD, a single track, or only the tracks programmed into the memory. In addition, the CD player has a scan feature that auditions the first 10 seconds of each track on the CD.
Rear seat headphone jacks are available in the Chrysler LeBaron coupe, New Yorker, New Yorker Landau, and Dodge Dynasty. They provide rear seat occupants with private listening through headphones. When headphones are plugged into the jack, the rear speakers are defeated. The front speakers continue to operate and may be faded out using the radio fader providing the front seat occupants the option of a quiet environment.
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