help with factory 1992 radio/EQ

[unruhjonny]

thanks for the replies;
Peter, your signature is quite funny


OK, here's what I found;

the following numbers are supposed to be EQ CDM's, which are compatible with non-EQ radios:
16072780
16087080
16140942
16147065
16169561
16172061
16172125
12341718(??)

the following are numbers which are non-EQ CDM's; if used with an EQ stereo, the EQ will not function properly:
16072800
16141203
16147065
16147075
16169551
16172115
2231934
6208545
2501
89AZTU
5358583(??)
16055070(??)

It is also worth mentioning htat other vehicles made around this time used the same radios as our trucks, one that comes to mind was the 1994 Sunbird my mom had from new.

I ended up finding three, and aqquiring two of them;
I found a 16140942 and two 16172125's
What I was annoyed with regaurding hte '2125 CDM's wahs that GM had apparently placed wide blue scotch tape over the Delco identification sitcker - but then I noticed that they also placed a small sticker on the end of the case with the last four digits of the model number!!

Lets hope I get this licked!!

 

[Donald Mitchell]

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Radios this old need servicing. Electrolytics Last a lot longer than one would expect but when they go they will take other parts with them. Radio like yours does not have any potentiometers to clean. Resistors can drift with age or go open or short but unless they test bad I wouldn't replace any. Usually if they check within 20% of their value they are ok. Capacitor would be my first suspect and you really can't tell anything by looking unless something really bad happened. Best practice is if they go thunk when they hit the garbage can they are bad.

 

[man-a-fre]

So did you have the wrong cdm for the eq or not?

 

[Eveready]

One minor point about speakers. "Even blown speakers will make a noise" is not true, at least for the Delco speakers that came with these trucks. I tested all four of mine individually when I first started getting ready to replace the radio. They looked physically intact but not a peep, even when hooked first to a verified audio source and then across a 9 volt battery. Not a single click NADA. I used the factory wiring with new speakers and they work perfectly.

 

[unruhjonny]

@Donald Mitchell
Thank you for your contribution, I may come back to it at another time.
Please don't be put off when I say that I try in earnest to stick to an old adage my former boss taught me;

K.I.S.S.

Keep
It
Simple
Stupid(!)

To that extent, I bought "replacement" radio and EQ units with the intent of installing them on the merits of nicer buttons (they would look nicer), and since upon my trial install (connecting them to the CDM) I was seeing the same EQ funniness, I figured there was something more amiss rather than just a malfunctioning EQ.

So did you have the wrong cdm for the eq or not?

This was the suspicion that I was going on this morning after reading on, and thinking about this - and from a members post in my "introduction" thread, I felt my suspicions were wholly justified.

So I bought these:

I installed the top one first, as it looked older, and was my guess of being the "bad" one...

But I was rewarded with this(!)

I also went to the yard with a list of roughly fifteen model numbers, in groups of EQ or NON-EQ;
After getting everything buttoned up, sure enough the CDM I removed was in the non-EQ group; 16172115

One minor point about speakers. "Even blown speakers will make a noise" is not true, at least for the Delco speakers that came with these trucks. I tested all four of mine individually when I first started getting ready to replace the radio. They looked physically intact but not a peep, even when hooked first to a verified audio source and then across a 9 volt battery. Not a single click NADA. I used the factory wiring with new speakers and they work perfectly.

I am actually quite pleased to read this.

I was apparently wrong on nothing from the radio being replaced, but I would be supremely surprised if this truck does not have the original speakers;
I see no evidence of the rear trim ever being removed, so I will assume that you are correct, and source a replacement set of speakers shortly.

Blown speakers would be wonderful, as compared to chasing wires for breaks!

 

[Eveready]

I am actually quite pleased to read this.

I was apparently wrong on nothing from the radio being replaced, but I would be supremely surprised if this truck does not have the original speakers;
I see no evidence of the rear trim ever being removed, so I will assume that you are correct, and source a replacement set of speakers shortly.

Blown speakers would be wonderful, as compared to chasing wires for breaks!

If you have the high trim option (the big wide plastic band from speaker to speaker), then they almost certainly have not been replaced. If that is the case it is a major PITA to change them and you have to carefully follow the procedure for removing the trim or it breaks. I have re-speakered two different vehicles from that era and never had any problem with the factory wires. On my old Dodge van I had to dig up the color codes as an idiot PO had cut the harness at the radio. I soldered on a new connector per the codes, installed new speakers at the other end and all works perfectly. My '93 pickup was much easier as the harness had not been cut . Likely no issue at all with the wires for you. Good luck and let us know how you come out.

 

[cngodfather]

A speaker considered blown usually means that the coil burned up or there is something wrong with the cone/surround. The result of this is either no sound or poor quality sound. I have seen in the past speakers that have the little wires (the ones that connect the speaker terminals to the speakers coil) wear out. Some of those wires are small copper wires wrapped around a nylon or fabric center core. When the copper breaks, it can touch sometimes and not others depending on vibration. As our trucks are reaching their middle age years, most of the time they do not age like fine wine. You said you wanted to keep the stock appearance. I am compelled to recommend that if you want to keep the truck, replace the stereo and speakers. The radio will die, the speakers will die. You might get lucky and last for the life of the truck. It may also die tomorrow. I would highly recommend changing it out for components that sound a lot better. This is just my opinion.

 

[Donald Mitchell]

16196186 is a bose cdm for camaro corvette and caddy, Looks like the same plugs. Wonder if it would work. Interesting!
https://www.google.com/search?q=199...AKHZNTAqsQ9QEwAXoECAoQBw#imgrc=XfdX0hCzTZZWAM

 

[AK49BWL]

16196186 is a bose cdm for camaro corvette and caddy, Looks like the same plugs. Wonder if it would work. Interesting!
https://www.google.com/search?q=1994+cadillac+bose+cdm+16196186&rlz=1C1CHBD_enUS834US834&tbm=isch&source=iu&ictx=1&fir=D_uM_ezrmGn2hM%3A%2CccsOY6a1hmpedM%2C_&vet=1&usg=AI4_-kS-00NLES6-ieajeo7FRqlRqSV4Mw&sa=X&ved=2ahUKEwjU6vX5nbnoAhWJmOAKHZNTAqsQ9QEwAXoECAoQBw#imgrc=XfdX0hCzTZZWAM

This IS quite interesting and changes things a bit, IF in fact they can be used in the trucks! I also GREATLY wonder if any of these CDMs are capable of running the later model 6-CD changers?? From what I can find, those units DID come with built-in CD players AND tape decks. Would be pretty cool if they'd fit the trucks but I don't think they would.

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[Texvet]

For whatever it's worth.... When I purchased my 1992 Silverado the radio and cassette player did not work. I purchased a known working radio and brain box. Installed it, and nothing (did not work, not a snap, crackle or pop, just like the original). Just as I was getting ready to throw the original and the replacement unit in the trash, and purchase an off the shelve,funky, put it the center of the dash unit. I decided to try an old speaker I had laying around. Touched it to the terminals on one of the dash speakers.... Out came the sound. All 4 speakers were dead.