Old car stereo concept advice?

[JHZR2]

On the 1991 MB 350sd that I got this September, the stereo doesn’t work fully. I haven’t messed with it much, it’s a Becker 1432 which has a face plate in the dash with cassette, and the tuner in the trunk, amp under the back seat, and 10 speakers. The unit turns on, the screen doesn’t always display. Power antenna goes up but no sound…

Could be dirty or blown fuses, or the sky’s the limit…

I like the car, it runs and drives really nice, but I really only stream on my phone anymore. So while I’ll do some cursory evaluation of the stereo, I’m not interested in spending big money to replace it in this vehicle.

I only like OE head units in my vehicles, an aftermarket monstrosity is out of the question. Ditto some other Becker or whatnot because of how the 1432 is setup. On other stereos I add fm modulators and Bluetooth dongles of various sorts to keep the oe look and get Bluetooth.

im just not that into rewiring a whole stereo either.

So the thought is this:

Leave the stereo head unit in the dash for oe look. Get a kenwood Bluetooth amp, and wire it into the harness for the original amps. See the connections and pin outs:

This would work because there’s power and all the speaker connections there. I’ve got constant power, ground, all the speaker connections, all right there…

Id lose the head unit, and radio, but gain an amplified Bluetooth system that is more native than modulators.

Any thoughts?

 

[supton]

Head unit alive or dead?

Am guessing the line signals follow whatever is the standard for 600 low levels signals. Id find a walkman and try to splice in, so as to drive the fader, and see what happens. See everything downstream works.

 

[wings&wheels]

Your plan seems like it should work, w/ the loss of tuning, etc. That said, I have found these folks extremely helpful over the years; Becker Auto Sound

 

[DuckRyder]

How many amplifiers looks like it has a tuner/amplifier and 2 amplifiers a right and a left. Id start by checking and cleaning fuses and grounds.

That said, assuming you can access all the speaker wires under the seat, yes your plan should work, make sure you keep any cross overs in the system but it doesn't show any.

 

[supton]

I have never been able to read automotive schematics. It may be worth some time redrawing that, possibly using actual colors for the lines, and make the classic "inputs on the left, outputs on the right" rendering. Or just getting onto one sheet of paper. Then add any markups for things you cut, spliced or changed.

If nothing else, a clean sheet drawing of whatever you wind up doing may be have value a few years down the road, when you have forgotten what you did in the past, and now want to change something (or repair it, as the case may be).

 

[Marcozi]

I'd start by checking the connectors. Clean them with a contact cleaner. Also, check the grounds for the head unit and the amps. It looks like "W12" is a common ground for the amps.

 

[atikovi]

Aren't there places that rebuild vintage radios?

 

[JeffKeryk]

I have a similar issue with the AM/FM Stereo radio in my old Vette. That was an expensive (and rare) option in 1968 cars.

 

[wings&wheels]

I have a similar issue with the AM/FM Stereo radio in my old Vette. That was an expensive (and rare) option in 1968 cars.

I had these folks rebuild the 1974 mono Blaupunkt Frankfurt in my Tr6 18 years ago...still works well; D & M Restorations

 

[Nick1994]

If you end up replacing it, Continental makes a nice European style replacement radio.

Continental Automotive

The safest and more convenient way to phone and listen to music with your mobile phone while driving.

www.continental-automotive.com

 

[Cujet]

I guess I don't see the appeal of an OEM radio, as they are so often terrible. There are acceptable looking modern options that will provide what you need. Unfortunately, that's not a plug n play as far as I can tell. So any way you slice it, you will be doing some wiring. Why not simply get full functionality along with bluetooth?

 

[brianl703]

If you end up replacing it, Continental makes a nice European style replacement radio.

Continental Automotive

The safest and more convenient way to phone and listen to music with your mobile phone while driving.

www.continental-automotive.com

That won't display title or artist info if you're streaming bluetooth. It just says A2DP on the display. If you care about such things.

 

[97prizm]

On the 1991 MB 350sd that I got this September, the stereo doesn’t work fully. I haven’t messed with it much, it’s a Becker 1432 which has a face plate in the dash with cassette, and the tuner in the trunk, amp under the back seat, and 10 speakers. The unit turns on, the screen doesn’t always display. Power antenna goes up but no sound…

Could be dirty or blown fuses, or the sky’s the limit…

View attachment 137859

I like the car, it runs and drives really nice, but I really only stream on my phone anymore. So while I’ll do some cursory evaluation of the stereo, I’m not interested in spending big money to replace it in this vehicle.

I only like OE head units in my vehicles, an aftermarket monstrosity is out of the question. Ditto some other Becker or whatnot because of how the 1432 is setup. On other stereos I add fm modulators and Bluetooth dongles of various sorts to keep the oe look and get Bluetooth.

im just not that into rewiring a whole stereo either.

So the thought is this:

Leave the stereo head unit in the dash for oe look. Get a kenwood Bluetooth amp, and wire it into the harness for the original amps. See the connections and pin outs:


View attachment 137860

This would work because there’s power and all the speaker connections there. I’ve got constant power, ground, all the speaker connections, all right there…

Id lose the head unit, and radio, but gain an amplified Bluetooth system that is more native than modulators.

Any thoughts?

Nakamichi makes a nice high-end aftermarket head unit but it looks plain and very stock

 

[FishFry]

I got this for my 41 Chevy (where I wanted it to be invisible, and also using the original on/off/volume knob.
Works just fine with my phone via bluethooth. There are a ton of different models. Some are quite simple (on/off/volume) like mine. Others have more controls like the one below, ans some are even playing music from a USB stick. Most of them have a Class D amp by Texas Instruments.
I didn't expect much, but I was quite surprised how good it sounds. And for 14 Bucks you can't go wrong.

https://www.aliexpress.com/item/1005004477889486.html?algo_exp_id=a9accaa4-5d00-4311-aa31-01ffffbf0ad3-45&pdp_ext_f={"sku_id"%3A"12000029302069200"%7D

 

[JHZR2]

I guess I don't see the appeal of an OEM radio, as they are so often terrible. There are acceptable looking modern options that will provide what you need. Unfortunately, that's not a plug n play as far as I can tell. So any way you slice it, you will be doing some wiring. Why not simply get full functionality along with bluetooth?

The appeal is that it looks OEM, and is OEM. Most every single aftermarket head unit looks terrible.

On top of that, the setup of these two part stereos makes it even stranger to run.

Nakamichi makes a nice high-end aftermarket head unit but it looks plain and very stock

Yes, they were popular with the E30 BMW folks because those came with something that looked similar. I can’t find those nice old school looking HU on their site anymore, many look like the usual gaudy stuff. And for what the $$ probably will be, I can take my system to Becker in NJ, and have it back to new…

I’d still keep my OE HU, use it only as an on/off signal, and then only have Bluetooth. I don’t really have any need for cassette, or even am/fm. Most fm radio is horrible anymore with so many commercials, and lousy music, and am stations I can get other ways.

 

[Tharber]

I'd get a dealer level scanner program and see if its something easy to fix first. I'm not sure about MB but I know I can trouble shoot the audio systems in all my BMW's with BMW Standard Tools. It was a free but complicated down load. One of my kids cars had terrible sound so I ran a scan and discovered there was a communication error with the amps, cleared it and it was perfect.

TH

 

[JHZR2]

I'd get a dealer level scanner program and see if its something easy to fix first. I'm not sure about MB but I know I can trouble shoot the audio systems in all my BMW's with BMW Standard Tools. It was a free but complicated down load. One of my kids cars had terrible sound so I ran a scan and discovered there was a communication error with the amps, cleared it and it was perfect.

TH

Not sure how that will work on a MY 1991 vehicle that was designed in the 1970s…

 

[brianl703]

Not sure how that will work on a MY 1991 vehicle that was designed in the 1970s…

I found a picture of the innards of that Becker radio and it looks a bit newer than 1970s design. Doubt it's new enough to support any kind of diagnostics, though.

 

[JHZR2]

I found a picture of the innards of that Becker radio and it looks a bit newer than 1970s design. Doubt it's new enough to support any kind of diagnostics, though.

Yeah they made a bunch that looked similar over the years, but I think the 1432 was used from ~90-94.

 

[brianl703]

Yeah they made a bunch that looked similar over the years, but I think the 1432 was used from ~90-94.

It has a 40-pin DIP inside of it, maybe microcontroller or CPU of some kind. Pictures not good enough to see a part number.