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944 Stereo System Update Cassette to CD
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Pelican Technical Article:

944 Stereo System Update Cassette to CD

M D 'Doc' Nugent


3-4 hours






Wire cutters, crimping tool, 10mm wrench, hand file, masking tape, Sharpie,

Applicable Models:

Porsche 944 (1983-89)
Porsche 944 S2 (1989-91)
Porsche 944 Turbo (1986-89)
Porsche 944S (1987-88)

Parts Required:

Blaupunkt AM-FM-CD unit (model RPD-550), red crimp on butt connectors (8)

Performance Gain:

CD listening

Complementary Modification:

Get some new speakers to go with your new stereo
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
     This project began with an annoying problem with my 1984 944's original Blaupunkt Monterey AM-FM cassette: anytime I'd touch the volume knob, a loud static crackle would blast through the speakers at full volume. With the cost of sound systems dropping significantly since 1984, I presumed it would be cheaper to buy a replacement than to have the original repaired. In the process, I'd be able to update from the media of the last century - cassettes - to the media of this century - CD's. The fact that I can now record my own compilation CD's on my home computer made the $120 cost of a new AM-FM-CD player seem like a fantastic bargain.

     I'd hoped that since the new AM-FM-CD was also a Blaupunkt (model RPD-550), installation would be a simple unplug-and-plug-in operation. DIN connection standards are not the same as they were in 1984, however, so installation was a little more complicated, but not much. NOTE: Other music systems' installation requirements may differ and other years of 944 may differ, but the general aspects of this article should still apply.

     Both units have the same physical size [ Figure 1], and I found that replacing the mounting frame [ Figure 2] wasn't required in this particular case - the old mount was the same size and had the same attachment points. The steps, then were:

  1. Disconnecting the battery,
  2. removing the Monterey,
  3. labeling the wires going into the Monterey and removing the antenna lead,
  4. cutting off the connectors from the eight 944 wires,
  5. connecting the new adapter to the 944 wires with crimp on wire connectors,
  6. plugging the adapter and antenna lead into the RPD-550,
  7. sliding the RPD-550 into the 944, and
  8. reconnecting the battery.

     The RPD-550 puts out 200 watts (50 per speaker) if the speakers are powered directly from the RPD-550's four speaker output pairs - this arrangement (explained in the manual) utilizes the unit's internal front-to-rear fader. Instead, I chose to run only two of the RPD-550's outputs (front left and front right) through the 944's front-to-rear fader. As I understand it, only 100 watts of power is available to the four speakers (25 watts each) with that arrangement. I did this because the speakers are stock 944 items, and I didn't want to overwhelm them or upgrade them at this time. It's not a big problem to change that later if I change my mind.

     I didn't need to remove the fader from its position in the console (in front of the shift lever and on the opposite side of the sunroof switch), but I took it out anyway, to photograph [ Figure 3] and try to understand the wire color coding better. Having it out didn't help, because only the fader end had different colors - on the other side of a six pin connector, were six identical (brown with red stripe) wires!

Now, in more detail, here's at least one way to swap the two units.

STEP ONE - Disconnect the battery

Find your 10mm wrench, open the hood, and then:

  • Loosen the clamp on the negative (ground) battery post. The negative post, if not marked, will be the one with the uninsulated wire attached to the clamp. Once loosened, remove the clamp from the post.
  • Next, loosen the clamp on the positive (hot) battery post, and remove that clamp from that post. The positive side of the battery will be the one with the red wires going to it.

     Leave the wrench anywhere except on top of the battery - if it jiggles around just right, it can short out the battery posts, and that's dangerous!

STEP TWO - Remove the Monterey

     Although others have told me they're removed a Monterey with pieces of a wire coat hanger, I sprung for a pair of Scosche DT-1 removal tools sold at WalMart for about three bucks.

  • Just jam them about an inch into the holes at the sides of the Monterey's face plate.
  • They snap into position, and you can then easily pull the unit out of its mount.

Two tips:

  • Aim the tools a little toward the outside of the Monterey - not toward the center of the unit. That's because the tools have to slide along the outside of the case (see Figure 4).
  • If the tools are difficult to insert through the holes in the faceplate as mine were, file the smashed down area - about '" from the tool's ends where the excess material is squished out to make the catches - until they're round.

STEP THREE - Label the connections

     As you look at the rear of the Monterey, you'll notice that all connection except the antenna input are in a black plastic area [ Figure 5]. Across the top are two speaker connectors (see [ Figure 6]):

  • The black jack is for the right (passenger side) speakers.
  • The white jack is for the left (driver side) speakers.

     Each connector has a blade and a pin to maintain polarity, but you'll be using color to keep things straight. What would help, though, is to attach a masking tape label to each pair of wires about 2" from its connector. Mark the black pair "black - right" and the white pair "white - left" since you'll be cutting the connectors off in a later step.

Across the bottom of the black plastic area you should find (left to right as seen from the rear):

  • a small red wire that goes to an inline fuse (mark this one "permanent 12v"),
  • a small whitish wire that goes to the antenna (to raise and lower it - mark it "antenna power"),
  • a small red wire loop that connects the next two (just leave this in place, you won't be using it),
  • a large red wire that shares a large white connector (mark it "ignition 12v"), and
  • a large brown wire that also shares the large white connector goes to ground (mark it "ground").

     These wires are shown in [ Figure 7] - I refer to all of them as "power wires" to differentiate them from "speaker wires."

     I recommend that you pull out the coaxial antenna lead cable [ Figure 8] from the Monterey at this point, but not label it. The reason for this exception is to help you remember that you DON'T want to cut the antenna lead off like you will be doing with the other wires!

STEP FOUR - Disconnect the Monterey

     You can now use a wire cutter to cut the connectors off each of the four individual power wires (in the last paragraph above) and the two pairs of speaker wires (in the paragraph prior to the last one above). Since the connectors are so out of date as to be unusable, cut the wires as close to the connectors as possible.

     Did you forget and cut the antenna lead cable? If you did, decide what sort of replacement antenna you want to buy. . . .

STEP FIVE - Connect the RPD-550 adapter to the 944 wires

     You'll need eight crimp on butt connectors (their color indicates their size - use the red ones). It's easier and makes a stronger connection it you use crimping pliers made for that job, but to each his or her own.

     You'll have to separate about the last inch of the speaker pairs, then remove the insulation from the last '" of each of those four wires and the four power wires.

     Once each of the 944's eight wires has a butt connector crimped onto the end, strip and crimp a wire from the RPD-550's adapter [ Figure 9] into the other end of each butt connector. The wires match this way (Important: 944 wire is listed first, then the adapter wire):

  • brown speaker wire with red stripe marked "black - right" goes to gray wire,
  • plain brown speaker wire marked "black - right" goes to gray wire with black stripe,
  • brown speaker wire with red stripe marked "white - left" goes to white wire,
  • plain brown speaker wire marked "white - left" goes to white wire with black stripe,
  • small red power wire with fuse marked "permanent 12v" goes to orange wire,
  • small whitish power wire marked "antenna power" goes to blue wire,
  • large red power wire marked "ignition 12v" goes to yellow wire, and
  • large brown power wire marked "ground" goes to black wire.

You might want to check this more than once - incorrect wiring can, at the very least, fry your new toy beyond hope!

STEP SIX - Inserting the adapter and antenna lead into the RPD-550

     I found it easier to push the antenna coax lead into the RPD-550 first. Make sure it goes all the way in, or you can have poor reception of both AM and FM.

     The adapter connector only goes in one way - note how one side's pins are spread further apart than the other side's pins.

STEP SEVEN - Installing the RPD-550 into the 944

Remove the face plate per the RPD-550 manual.

     Tuck all the cables as far back into the hole where the Monterey was, then - making sure the RPD-550 is "right side up" - push it into the mount all the way until it clicks.

     Finally, replace the face plate. Looks good, eh? Turn it on . . . . no sound? Good. That means you correctly disconnected the battery in Step One.

STEP EIGHT - Reconnecting the battery

     First, place the clamp with attached red wires over the positive post (typically to the rear of the vehicle, but don't rely on that), and tighten with the 10mm wrench. (I don't know where YOU put it!)

     Second, place the clamp with the attached uninsulated wire to ground over the negative post, and tighten it with the 10mm wrench.

     If there was an insulating cover over the positive post, replace it as 944 batteries have a bad habit of shorting out against the hood without one.

You're done - pleasant tunes!

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Comments and Suggestions:
Henry Comments: I recently bought a 1993 968, which is in very good condition. However, a previous owner installed an aftermarket mini-disc stereo which is shot. Upon taking it out to replace it, we found that the antenna wire had been butchered and crudely soldered, leaving very poor reception. I've found a replacement antenna booster amplifier, but can't find any guidance on installation. Got any suggestions?
August 6, 2016
  Followup from the Pelican Staff: Use the manual that came with the booster. I don't have info on it. You can replace the antenna wire if it was damaged, as reception may be poor if you repair it.

Give The Pelican Parts parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
TTMach1 Comments: I'm trying to install a NEX 8100 into a 02 TT W/ Bose not sure if MOST or not. The yellow plug only has 1 wire in it, so I can't use the RCAs. I got a eurospeed wire adapter and wired up by matching the colored wires but the head unit does not turn on. Is there a wiring guide for my setup?
March 1, 2016
  Followup from the Pelican Staff: I don’t have that info.

We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
RedSled85 Comments: thanks for the locktite blue reminder, doing both doors next weekend.
October 11, 2009
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts

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