Jump to content

Done something too stupid not to work - radio


padgett
 Share

Recommended Posts

OK was exercising my 88 Coupe and discovered the radio I bought new from MNR over a decade ago had taken a dump. Controls work but no sound. Pulled the lid (4 screws & shifter) and swapped in my spare from who nose where. Got tape player but not radio. Since need radio for bluetooth this was NG.

 

As going back in house I noticed something on the shelf, a 90 dash radio that said "good. Somewhere back in my brane a synapse fired and took a closer look. Gee willikers Sandy..

Four screws and the tuner/amp module was removed from the chassis. Plugged into my 88 and is working a champ.

 

Now my question is since I like having a spare, which is worth more: a working 88 module or a similar 90-91 dash unit ? Could use a spare of either that works and less expensive delivered to 32819. Alternately does anyone repair the module for less than the cost of a spare ? YWTK.

Edited by padgett (see edit history)
Link to comment
Share on other sites

  • 2 weeks later...

Padgett - there seems to be a fairly wide range of compatibility between the CDM modules.  I've swapped around ones dated from 1989 to about 1995 (Cadillac versions).  The only 'weird' one I've found was a pull from an early '90s Pontiac Bonneville.  It's CDM and associated head unit really needed to be paired together to tune correctly.

 

I've got about a dozen various Delco head units from the era.  There are three basic flavors of the CDM modules: The 'bass/treble' version, the '5-band EQ' version, and the Bose version.  Both the regular bass/treble and the 5-band version have built-in amplifiers.  The Bose version, also bass/treble, does not have built-in amps.  The 5-band and Bose versions support CQUAM AM Stereo, the bass/treble version does not.  From 1990 onwards, AM tuning goes up to 1710 kHz instead of 1620.  And at least the '93 or '94 and '95 Caddy Bose units are spec'ed to the AMAX (higher performance AM) level.

 

Comparing the guts of the different years, you'll see increasing integration over the years.  The '89 module that I have includes several 'daughter' boards.  By the time you get to '95, there are no daughter boards and many fewer components on the main board.  The last year Buick used CDM radios was in '94, and Cadillac in '95.  I think there may have been later uses in other GM vehicles.

 

I have not played with the CRT setup at all.  But my guess is that any of the CDM modules, perhaps excluding that Bonneville version, would work in your '88.  Might only tune AM up to 1620 kHz though.  I have a very rare '89 Cadillac Bose CD head unit, and it only tunes up to 1620 - regardless of which CDM module is in it.  I also have a '91 version of the Cadillac CD head unit (they were only made from '89 to '91) and it tunes all the way to 1710.

Edited by wws944 (see edit history)
Link to comment
Share on other sites

One I pulled from a 90 Reatta dash unit tunes to 1620 then wraps. Don't really care just need the tuner for FM Handsfree. Still need a good working spare or someone who can repair.

Link to comment
Share on other sites

If I remember correctly if you unplug the radio unit form the car. And plug it back in it will default to tape mode. Did you select the radio mode on the screen to switch it after you connected it ?

 

Also I followed instructions I found that scrap the outputs of the factory radio. ( this eliminated all the caps and chips for output. ) Wired in RCA out from pre-amp to Sony Amp in trunk.  I have been running this setup for 3 or 4 years now with no issues. This also eliminates the DNR function of the radio.

  • Like 1
Link to comment
Share on other sites

15 hours ago, padgett said:

One I pulled from a 90 Reatta dash unit tunes to 1620 then wraps. Don't really care just need the tuner for FM Handsfree. Still need a good working spare or someone who can repair.

 

That is a function of the CRT setup acting as the 'head unit' for the CDM module.  It is only programmed to go up to 1620 kHz.  From 1990-onwards, the head units are programmed to command the (1990-onwards) CDM modules to tune higher.

Link to comment
Share on other sites

On 5/14/2020 at 4:08 PM, handmedownreatta said:

what is the purpose of going above 1620?


There have been a number of efforts to re-vitalise AM broadcasting over the past few decades.  In the 1980s, some radio frequencies just above the traditional AM broadcasting band were freed up.  (E.g., the ancient “calling all cars” police band and also an obsolete LORAN system.). So the AM broadcasting band was expanded a bit to include the so-called “X band” - which refers to frequencies between 1630 and 1710.  A number of broadcasting stations were, and are, licensed there.  Advantages included less interference from other stations on the same or adjacent frequencies.  Also a number of the X band stations broadcast in C-QUAM AM stereo.  (Though AM stereo isn’t limited to just X banders.)

 

There was also an effort to raise the technical standards of the broadcasters and radio manufacturers called AMAX.  GM/Delco actually advertised at the time (early 1990s) that that the AM side of some of their radios were AMAX compliant.  But by the mid-1990s both AM stereo and AMAX began to fade away.  Nonetheless, there are still like around 100 stations around the U.S. broadcasting AM stereo.

 

Locally to me, in the San Francisco Bay area, I can only receive a single AM stereo station - KDIA - which is also an X bander on 1640 kHz.  It lights up the ‘stereo’ light in my Reatta just fine during the day.  However their night time transmitter does not.  Unfortunately KDIA is a religious broadcaster - so their programming is of no interest to me.  Just a ‘test signal’.  :)

 

AM stereo can sound really good though.  A number of AM stereo broadcasters do their internet streams via an AM stereo monitoring receiver - rather than simply streaming the input from a tap to their transmitters.  Of note, WXYG in Minnesota and WION in Michigan are two examples with pretty decent rock music formats.  (Especially WXYG.). If I lived locally to one of them, I’d certainly be mildly interested in radios that supported AM stereo.  As it is, I can stream them via the tunein app on my phone, and even natively in the case of my Tesla’s infotainment system.

 

Of interest to radio buffs, but probably few others...

Edited by wws944 (see edit history)
  • Like 1
Link to comment
Share on other sites

The story of broadcast radio in the US is a sordid one of politics and payoffs and involved many battles both legal and ill. Probably the most notorious was the destruction of the Yankee FM network in New England when the FCC, influenced by David Sarnoff, moved the FM bands in 1948. For some interesting battles look up DeForest vs Edison and Armstrong vs Sarnoff.

Today everything I want to listen to is on my cell phone.

Link to comment
Share on other sites

I have never been able to get too excited about listening to music in a car. I agree that it is fun to drive around and listen to some tunes but seriously, expecting to hear great music in a car is like expecting to get great food at McDonald's.  Sitting in the drivers seat is the worst position acoustically you can be to get true stereophonic sound.. You are all the way to the left of the car with a speaker just inches away from your left ear and your right ear is about 4 feet from the right speaker. Then you throw a sub-woofer in the trunk to get a little thump that most front car speakers aren't capable of. You would get much better sound if you straddled the console. OR put on some good headphones so you could actually hear music in stereo as was intended when the music was recorded. I know you can mess around with the balance controls and the equalizer to make it better but I always find the sound lacking.

 

I hardly ever turn on the radio because when I'm in my Reatta I want to enjoy the driving experience. If I want to listen to music I go here so I can sit in the center of the speakers in comfort and enjoy the music

 

polk2b-1.JPG.f965e2771f0592bd5fea352a862fb842.JPG

Edited by Ronnie (see edit history)
  • Like 2
Link to comment
Share on other sites

1 hour ago, Ronnie said:

I have never been able to get too excited about listening to music in a car. I agree that it is fun to drive around and listen to some tunes but seriously, expecting to hear great music in a car is like expecting to get great food at McDonald's.  Sitting in the drivers seat is the worst position acoustically you can be to get true stereophonic sound.. You are all the way to the left of the car with a speaker just inches away from your left ear and your right ear is about 4 feet from the right speaker. Then you throw a sub-woofer in the trunk to get a little thump that most front car speakers aren't capable of. You would get much better sound if you straddled the console. OR put on some good headphones so you could actually hear music in stereo as was intended when the music was recorded. I know you can mess around with the balance controls and the equalizer to make it better but I always find the sound lacking.

 

You should try the 15-speaker Premium sound system in a Tesla some day.  Zero drive train noise, so only tire noise remains.  Full internet connectivity for streaming audio via tunein, slacker, spotify, FM radio - both analog and digital, and bluetooth from your phone.  Fantastic road car - and I am a bit of a road trip buff.  And of course I have to note that in the Model S and X, the volume control "goes to 11" - instead of 10.  :D

 

As for my Reatta, especially since it is a convertible and is usually driven "top less", I mainly ask for clean sound and a lack of problems at reasonable volumes.  As we all know, the foam surrounds on the speaker drivers of the era were very prone to disintegration over time.  And the capacitors in the amplifier section of the CDM modules are also a problem.  I've also done a lot of experimentation with the CDM modules and head units (have a collection of about a dozen each) in terms of adapting the CD player harness for AUX IN, and using low level outputs from the Bose modules to drive external amps.

 

 

Quote

 

I hardly ever turn on the radio because when I'm in my Reatta I want to enjoy the driving experience. If I want to listen to music I go here so I can sit in the center of the speakers in comfort and enjoy the music

 

polk2b-1.JPG.f965e2771f0592bd5fea352a862fb842.JPG

 

Beautiful living room setup.  I'm sure you enjoy it!  Mine isn't quite as pretty.  But it is interesting in its own right.  (Modern sources feeding vintage McIntosh amps and Altec Lansing VOTT.)

Edited by wws944 (see edit history)
Link to comment
Share on other sites

14 minutes ago, wws944 said:

Beautiful living room setup.  I'm sure you enjoy it!  Mine isn't quite as pretty.  But it is interesting in its own right.  (Modern sources feeding vintage McIntosh amps and Altec Lansing VOTT.)

Thanks. I like the vintage stuff myself. Listening to music is one of my other hobbies. :)The speakers are Polk SDAs powered by a 200 wpc Adcom 555. Both built in the '80s but have been updated with new high quality caps and resistors. The preamp is a newer Marantz made to handle the home theater inputs. It can be switched to "Pure Direct" when just listening to music.

Link to comment
Share on other sites

2 hours ago, Ronnie said:

I hardly ever turn on the radio because when I'm in my Reatta I want to enjoy the driving experience. If I want to listen to music I go here so I can sit in the center of the speakers in comfort and enjoy the music

       I call that "listening to the song of the machine". True story from my trip home after winter storage yesterday: I turned the radio on to adjust the time and such, aftermarket 25 year old Pioneer din and a half, and discovered it is non functional, then remembered I noticed that last year before I put it away🙉

  • Like 1
Link to comment
Share on other sites

And the rest of the story. Found I had a shorted fan controller that was taking down the whole electrical system. Not sure if other radio modules work of was battery being pulled too low. Had a few spares so just replaced the module, must have done before since only two front screws. Royal pain to remove without pulling AC sensors. Fixed now.

Link to comment
Share on other sites

3 hours ago, Dashmaster said:

KDirk wrote this up. This is the guide I used.

Ronnie this might be a good one to save to the ROJ.

 

I read through that thread.  It is good information but way too technical for the majority of the people who visit ROJ.  I've not been adding anything to ROJ because I don't know if anyone goes there anymore.  ROJ and this forum are all but dead compared to the way it was a few years ago.

Link to comment
Share on other sites

Ronnie, I still think the ROJ is still used a lot. I know I use it.  Hoping to do some projects on my Reatta that might go there. My Car is off market for now. If I do plan to sell it again it will be on BAT.

 

Hope you are doing well. I will PM you soon.

 

Thank You and everyone that has been on the Forum and ROJ. As I have said before my car would have been in the scrap yard years ago without both of these sites, and I have learned so much from these sites and from all the work I have done to my Reatta.

 

Link to comment
Share on other sites

Would be even better if we had a way to host the service and parts manuals again. I do have some excerpts (e.g Radio and "Cranks but does not run" for training purposes that should not violate any copyrights. A good lawyer could probably say that since they were on line for so long they passed into the public domain.

 

Wonder what this is. And is best skipped unless you need tidbits on the Delco-Moraine power brake diaphrams or where the connector is on a Ford Probe. Waste of a double sawbuck. Not for a specific year, rather a mismash of all years plus. Engine codes end at E041.

Edited by padgett (see edit history)
Link to comment
Share on other sites

Padgett you could host the manuals on your website or I would be happy to host the manuals on ROJ. I could even password protect them as was done before if needed.  The problem is a website owner would be putting themselves in legal jeopardy unless written consent could be obtained from the copyright holder(s) to put the complete manuals online.  You can get by with posting a page or photo for educational or illustrative purposes in an article but when you post a manual it is a different story.  A good lawyer might could argue that they are in the public domain but the problem with that is I don't have the money to pay a good lawyer to argue that in court if I get sued.  The best bet for getting the manuals accessible again is for the Reatta Club to take on the project. That way it wouldn't be one person having to shoulder the risk of their website being taken down or the cost of fighting a lawsuit.

Link to comment
Share on other sites

Oh I agree though I suspect the chinese investors have other problems right now and only the 89 FSM is available from helm (in print). I wonder if Bisko would be interested ? Problem is our scans are not searchable.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...