Write-Up: Replacing bulbs in a G-Body Riviera head unit

this is how i replaced the bulbs in my radio. i messed up the ribbon that runs the display messing up the unit, so here's how to do it and how to avoid the mistakes i made.

first, remove the bottom plate. take out the small screw seen at the top of the following picture and gently pull this plate off.


second, pull the cassette player off by removing the screws like in the first part.


next, remove the white ribbon fromt the socket by gently prying up and give some slack to remove the front.

next, remove the front display by pulling the volume control knob off (be careful not to lose the spring behind it and remember how it goes back together) and the pull up on the tabs and gently pull the front off. be careful of the white "legos" they should come off with the face and by doing it this way, you shouldnt do what i did to the white ribbon.


now, its time to fix all the bulbs that were out. carefully take the blue condoms off the ones that need replaced. heat up the solder and remove the old bulbs. solder in new bulbs and put the condoms back on. i used radio shack bulbs (part number 272-1092: 2 per package). put it back together and hopefully everything works again. HTH

I just finished doing this exact job without realising that there was already a write-up for it. I realize most Riv owners have moved on to better head units, but I like the look of the stock unit, especially at night when it’s all lit up in relationship to the rest of the dash and interior. Paul has done a great job, but hopefully people can benefit from my contribution......

Here’s the unit…

Pull the volume knob off, followed by a spring and the volume indicator

Gently lift up on the eight tabs holding the interface to the unit. All eight will have to be slightly off for it to come off.

Remove the bottom cover by removing the one 3/16 hex head screw and then lifting up on the screw side.

Now you will have to remove the cassette player unit from the head unit, it is held on with either three or four 3/16 hex head screws depending on the year.

With the cassette player removed, place it to the side, or have a friend hold it while you pull out the two plugs that hold it into the head unit. NOTE: In some models you will have to first remove the ribbon as some cassette player plugs are located behind the ribbon.

To remove the ribbon, slide a small flat screwdriver under each of the black tabs that are on either side of the ribbon that connects the head unit to the front interface. With the locking tabs lifted up, you can now pull out the ribbon that connects the head unit to the front interface.

With the ribbon released, you can now separate the board and interface from the unit.

To separate the board from the user interface, you have to remove a few small Philip screws. Think there are about eight or nine of them. One is underneath the ribbon. Make sure, when you separate these two that the interface is always kept face down, otherwise all the little buttons and plastic bits will fall off as nothing is holding them in at this point. And it is quite a puzzle to put back together.

Here you see the display board and the back of the user interface.

Here is what the display board looks like, there are a total of 18 lamps to replace. You can go ahead and just replace the lamps that are out, but I decided to do ‘em all.

Here are the tools you’ll need to extract and install the lamps. Soldering Iron, solder paste and the solder itself.

On the back of the board behind each lamp you will see the two “feet” that are soldered into the board. They are pretty close together, so be careful when heating up the old lamps and soldering the new ones into the board so that you don’t solder them together.
Basically, you need to heat up the back of each lamp prong while pulling on the lamp on the other side, eventually the lamp will come out.

These are the bulbs I bought. They are 3mm 12V automotive lamps that I bought from an electrical supply store. The blue condoms have to be removed from the old lamps and re-used here. The black pieces are the bases that I also separated from the old lamps and re-used with the new ones. They will keep the lamps flat and stable on the board.

Hopefully that helps someone out. My dad and I have figured out the problem on the tape players too, but we need to find a replacement gear to test it, if people want, I can do a write up to repair the tape decks once I have it. Cheers

Excellent write up and thank you very much for taking the time to document your work, it will be very helpful.
(I didn't know there was a write up already either. But more info and pictures can't hurt.)
I also prefer the look of the stock head unit.

To answer your question about the tape decks, YES. Many of us have problems with the tape decks that we have either just decided not to use them or have spent the money on a used replacement head unit assembly.

I know, I would much rather fix things like this if possible than replace. Not because I'm cheap, but I like working on things, as long as they are on the bench.

BRAVO, BMD!!

BMD wrote:

I realize most Riv owners have moved on to better head units...

I disagree... hopefully.

Quote :

...but I like the look of the stock unit, especially at night when it’s all lit up in relationship to the rest of the dash and interior. Paul has done a great job, but hopefully people can benefit from my contribution......

I totally agree with you about the way they balanced and matched the lighting across the dash & doors of our cars. I've already replaced my own tape deck with a brand new unit to keep it stock... Also, anyone else ever notice the cool way that the lighting in the push-buttons switches from the preset-numbers to the tape/CD functions when you change sources?

Thanks guys, glad I can help!

Eldo wrote:

Also, anyone else ever notice the cool way that the lighting in the push-buttons switches from the preset-numbers to the tape/CD functions when you change sources?

Yeah, I definately agree, that looks neat Mark.

I will get any tapedeck info up when I have it, also I documented my repair of the HVAC unit. Its basically the same job as the head unit, but less complicated.

Nice job, BMD. I'm a big fan of the OEM head in these cars. I use mine to drive a 300 Watt audio system and it sounds great.

One question: did you verify the original LEDs were rated 12v in the factory head? Many times there is a voltage regulator that steps down the PC board voltage to 5v or even lower. Sometimes LEDs are also trimmed with specific resistors to get the brightness right.

How is the brightness level compared to the rest of the dash?

Thanks Aaron. I didn't know that a voltage regulator might reduce the voltage on the board, so I never checked to see what they original lamps were rated. The lamps I bought were automotive and recommended for this type of work and the brightness level perfectly matches that of the gauges.

AA wrote:

Nice job, BMD. I'm a big fan of the OEM head in these cars. I use mine to drive a 300 Watt audio system and it sounds great.

One question: did you verify the original LEDs were rated 12v in the factory head? Many times there is a voltage regulator that steps down the PC board voltage to 5v or even lower. Sometimes LEDs are also trimmed with specific resistors to get the brightness right.

How is the brightness level compared to the rest of the dash?

radio has "grain of wheat" bulbs, not LEDs.

HVAC head has "grain of wheat" bulbs for instrument panel lighting and amber LEDs for status (on) indication.

Albertj