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Anyone who still has the factory series 4 (86-88) Clarion-made factory stereo with the full-logic cassette deck, I have some information I want to share.
General:
Switches and pots should be sprayed with contact cleaner if you hear pops and crackling when you change the volume.
Be careful when removing the plastic face plates. The side tabs will break off if you force anything. You can repair them by using a thin piece of plastic (for increased surface area) and epoxy.
All the night time illumination and EQ sliders are lit by 12V bulbs that are soldered onto the boards. You can replace them with 3mm high-brightness LEDs with resistors soldered in-line. The EQ controls actually use a single bulb lighting 9 fiber optic filaments, a single 5mm high-brightness LED will do the job. Be sure to insulate the LED's leads and watch polarity. Get the polarity reversed and they will not work. If an exposed lead shorts to ground, you can fry an LED.
RT-9035C - AM/FM radio and preamp -- no internal amplification
The radio is actually very good at pulling in stations without an antenna. With no internal amplification, you can just make simple RCA adapters and plug straight into an external amp. If you have crackling noises or drop-outs in your volume control, you might be able to remedy it by dismantling the unit and spraying contact cleaner into the pots.
If that doesn't solve the drop out, you will have to either replace the volume control or use an external preamp and bypass the factory preamp completely. This is possible since the audio in and out goes through the DIN8 cable.
The LCD is backlit by a single 12V bulb that's attached to a reflector. You can splice in a new bulb or a wide-angle white LED. Narrow-angle LEDs will not properly backlight the LCD.
PT-8052C - full-logic cassette player
Factory parts for these stereos may or may not be available depending on what you want. The large belt is no longer available. However, replacement belts from Consolidated electronics fit and work perfectly.
If you have a problem where a cassette inserts but then ejects or does not play, replace the belts.
While you're in there, clean the cassette mechanism per this procedure: http://www.vintage-electronics.cc/cassetterepair.pdf Remember to use alcohol only on the head and metal parts and rubber-safe cleaner on the pinch rollers and plastic gears. I used light all-purpose oil on the metal caspian gears and silicone-based grease on the rest. I didn't use WD-40 at all.
When you replace the belts, if you insert a tape and the mechanism rapidly clicks and then ejects the tape or clicks when you eject a tape, the mechanism's eject gear is out of alignment. You want the notch in the gear to be aligned with the "stud" when the mechanism is at rest, you can adjust it by removing the big belt and turning one of the large metal gears to move the mechanism or carefully rotate the gear with a screw driver or pliers.
While I had the cassette deck apart, I found that a lever switch on the cassette mechanism, with brown, red and orange wires, is what switches power from the radio to the cassette deck when you insert or eject a tape. The brown wire feeds power, the red wire powers the deck, and the orange runs the radio. If you want to build an auxiliary input box that cuts power, keep those wires in mind.
Now, as for adding an auxiliary input, you have two options: build an auxiliary input adapter that plugs into the DIN-8 connector between the radio and cassette player or EQ, or take the EQ out of the loop and install a preamp. The radio listed has no internal amplifier, so you can just make some RCA adapters and plug the output of the radio straight into the input of the preamp, and use the preamp's second input for MP3s.
Building an adapter wouldn't require more than a couple of DIN-8 270-degree plugs, 20-18 awg wire, two small 12v relays (one to cut power, and one to switch in the audio signal) a pair of RCA input jacks, a SPST switch and a small project box and proto board.
At this point, I am waiting on pacparts.com on whether they can get a new volume control or not. To my knowledge, I no of no generic replacement part for the volume/balance/on-ff and fader/tone control pots.
Very cool project. I've always disliked the looks of aftermarket head units in fcs. What I'd really like to see is how to add something like a Bluetooth audio receiver that can be paired out of site. The other retro fits all add ports to the front of the stereo and require running in plain view.
My plan is to add a Parrot MKi series kit, which has MP3 playback as well as hands-free bluetooth. The mute wire can ground-switch a relay to cut in its audio when you receive a call; it has a line-out as well. The display and SPST switch (to manually switch in audio) could be hidden in the ashtray (the MKi9100, the 9200's display might be too big).
"Now, as for adding an auxiliary input, you have two options: build an auxiliary input adapter that plugs into the DIN-8 connector between the radio and cassette player or EQ"
In my '88 Vert I essentially did this. My model head unit was designed for a component CD player that plugs into the DIN-8. The FSM identifies what each pin is for. My goal was to install an aftermarket CD changer to directly input into the head unit. I found a Sony that had the needed negative trigger wire akin to the Factory Cd player. Wired everything up to the correct pins, and whallah. My head unit thinks my CD changer is the factory cd player and reacts accordingly.
Then I got an old XM radio also made by sony. A/B switch module into the same circuit feeding the DIN-8, and I now have XM radio playing through my factory head unit. Or flip the swtich to the B position, and it'd the CD changer.
One more thing about cassette players that I should add. If you are playing a tape and the pitch changes (goes slow and normal) and/or if you switch sides using the prog button then it switches back, there are two different things you can do.
1. Try a different tape and see if the same problem occurs. If it doesn't, tighten the reels on the problem tape and try it in the player.
so my stock speakers are pretty much shot at this point. the stereo itself works fine and definitely want to keep it, but i want to upgrade the system. is it possible to run this stereo unit directly into an amp? id rather not cut out the equalizer if possible.
i'm new to the whole stereo thing so i'm just trying to get my facts straight.
It depends on the type of radio you have. Some radios have internal amplification for one pair of speakers only, while others have no internal amp at all; check the FSM to identify the type of stereo you have. Radios with no internal amp only require a 1/4" female quick-disconnect to RCA adapter. You can then plug directly into the amp's line-level inputs.
i want to continue to use the factory S4 stereo, i have the one with the equalizer and cassette player, but no CD player. you specified in the OP that the unit doesn't have any internal amp correct? is that just the radio or does that also apply to the cassette deck?
The volume control part is still on backorder, so I needed to try something else. I turns out that DeOxit contact cleaner is not actually meant for lubricating pots. They actually have a specific product called FaderLube. I ordered a small tube (which is all you really need) and followed the directions; a few drops in each pot and work the controls through their range 40 times. I repeated it three times, then hooked it up.
Whereas the contact cleaner only cured the left channel dropout for a short while, I've been using the preamp on and off since using the FaderLube over a week ago, and it's still working properly.
As for the auxiliary input box, I succeeded in building it and it works. I have some notes.
Unlike my previous posts, you do not need to make any internal modifications to the headunit. You just plug the unit in between the EQ and the radio using DIN8 270-degree cable assemblies from Digikey.
Using a small 12v SPDT relay rated at 10 AMPs, you can switch power between the radio/cassette and preamp only by running power through pin 3 on the DIN8 cable. Power comes from the ACC wire. Important note: I confused Pin 3 and 5 (audio signal ground) and reversed them. The wire colors on the DIN8 cable assemblies from digikey are orange and brown. For sanity sake, the brown wire is +12V and orange is signal ground, but double check using a voltmeter. If you reverse them, either the relays will click constantly or there will be a hum in the preamp and no sound.
Pins 1 and 7, Input L and R respectively, green and yellow wires, can be hooked up to a DPDT relay or simply soldered inline. I went with a relay since one was on hand and I wanted to cut other sources out of the loop; consider it an option.
Finally, the box has three wires: +12ACC in from the body harness to adapter, +12VACC out to radio and ground. The ground wire, when grounded, swtiches in auxiliary and cuts power from the radio/cassette, removing ground restores normal operation. Simply hook the ground wire up to a switch (also wired to ground) or a ground-switched mute wire from a hands-free kit. I'm using a two-position rocker switch, position one runs auxiliary input, off is normal operation, and position two cuts in only when a device like a hands-free cut receives a call.
I have a similar unit in my 1987 GXL, complete with AM/FM, cassette, equilizer and working power antenna. A few years back, my left rear speaker was constantly crackling as I drove down the road. It seemed any little jarring would cause the sound to break up(adjusting the volume wasn't a problem.) I went to my local auto salvage yard and pulled the shock tower bucket, complete with speaker and amp. Replacing that, solved that problem.
Now, my front left speaker is acting the same way. That speaker doesn't have it's own individual amp, though. I believe it gets fed from the amp on the passenger side, mounted under the glove box, which also drives the front passenger speaker. I think my stock paper speakers are all fine too; they are not blown, so I don't see a need to replacement. How do I fix that?
Can I buy a standard auto amp? How many watts is OEM stock? Can I use that to drive the two front and also the two rear speakers? I probably need to run new wire, right?
I haven't pulled out my stereo yet, but does the stock unit come with these cables, or did you have to fabicate them yourself? https://www.facebook.com/media/set/?...bdfc1c&theater
Is that what I need to feed the exteral amp?
The front dash speakers are powered by a two-channel amp located in the right front speaker enclosure. Each rear speaker has its own 1-channel amp. The crackling may have been caused by bad solder joints. You might try removing the old solder with a soldering wick and applying new solder at the speaker and input connectors.
The cables I used are adapters I made using Switchcraft RCA female connectors, two-conductor shielded cable and 1/4" quick-disconnect female crimp terminals. With them, you can interface the factory headunit with any aftermarket amp. The preamp section on the factory headunit seems decent enough, but you'd have to increase the gain on the amplifer and that will bring more hiss.
CD players were available from 87 or 88 on, I think. Does the CD player light up? Do discs load, does it spin up? It might require new belts (if it's belt driven) or just a cleaning. If it's having trouble reading discs, it might depend more on disc quality than the mechanism itself; older CD players from that area are very picky and don't handle scratched discs like modern players and drives do. On the other hand, it could be a weak laser or need an alignment (the latter will require a service manual or someone who knows how to fix it).
When cleaning the lense, use a soft lint-free cloth and plain soap and water or an appropriate lense cleaner. Do not use alcohol to clean the cd's laser lense.
I recently picked up another unit off eBay, the one that was in my 88 GTU with the non-logic cassette deck. It wasn't working when I got it. I could insert and eject a tape, and the program and other buttons would light up, but it would not fast forward, revind or play. When I open up the dust cover and remove the tape mechanism (four screws), I found that the original belt was stretched. I swapped in a new belt and it was working again.
Bit of a necro but this is good information. Just did mine, couple things.
Ceitron does charge a fee for not buying in bulk, that and shipping ended up costing a bit over $20 for $5 of belts.
The tiny screws strip really easily, ridiculously so be careful and hope you don't get one stripped in the wrong place. You can get away with not having to unscrew certain portions but depends on where.
Belts sizes worked, did feel a bit loose, not sure how tight it's suppose to be.
Small belt has to go under a gear, other places have said to unscrew the plates so you can have a bit of lift to slide under the gear, I stripped my screws trying to access it and ended up jamming it into the gear to slip under.
Also get some contact/electronic cleaner while you're at it for the *****.
Otherwise it's easy enough to do just be careful not to strip the screws.
I never even noticed this thread back in the day. In 2012 I had one FC with only an aftermarket head unit.
Thanks for reviving it, because now I've got two FC's that are complete and need a factory stereo "overhaul."
I don't know if anybody here has recently looked at the current state of the single-din aftermarket head unit market, but as an amateur audiophile I find the selection of decent units to be quite depressing. It's all just the same old junk we had in the early 2010's getting rearranged to look "new" and "modern," bloated with features I'll never use.
Given the above, I've been wanting to restore my original stereo and add an aux jack to it. My main issues with the factory units are:
- Poor radio reception (radio even likes to stop working completely)
- Driver's front speaker doesn't come on (the pot is dirty.)
- Poor quality High-end and Low-end frequency response from the original speakers. (Because original 1980's speakers/amps.)
Given the plethora of info on the factory stereo in both my S4's, I plan on accomplishing several goals when I attempt to resto-mod the factory stereos:
- Eliminate the factory amplifiers in favor of an aftermarket alpine "brick" unit
- Replace the factory speakers, but retain the enclosures
- Possibly add a tuned port to the factory enclosures if possible, based on an aftermarket speaker's specifications.
- Relocate the rear antenna and cover the hole in the body.
- Add an auxiliary input.
If anybody is interested in an outline of this, I can start a thread on it when I begin the project after winter. If not I'll just post a few pics in this thread just for posterity.
Given that my original Facebook links are no longer any good, here are some of the pictures from back in the day. I no longer use the factory headunit (though I still have it) and am using a period-correct Clarion AM/FM cassette deck and Kenwood EQ through a switcher and line-driver.
Strictly speaking, you don't need a relay to cut audio in and out. All the sources are connected to each other on the same audio pins. A 12-volt high from any source cuts out the other source. When you insert a cassette, the deck sends out a 12V-high that cuts out the tuner until you eject the cassette. There's no firmware or data being exchanged between the units. It's just audio, power, illumination, control signal and ground. The trick to making it work is avoiding hum and, if using a cable assembly, knowing which wire is which. From there, you can add whatever source you want and even set it up to automatically cut in or just use a regular toggle switch.
Your best source of information on pin-outs and what is what is going to be the Body Electrical System and Wiring Diagram sections of the Factory Service Manual. That is where I figured it out. Repair manuals with schematics for some of the Clarion units themselves can still be found and purchased online in printed or PDF form.
The only reason I stopped using the factory headunit is because the radio tuner died. I don't know if it was simply due to age or a short circuit or my own tinkering. The other thing is that when you turn the stereo off by pressing the on-off ****, there is a sharp high-pitched thump before the external amplifier turns off.
The only other thing is that DIN 8 270-degree male connectors aren't easy to find. You could get around this by not using the boot and using heatshrink and tape to make your own strain relief or using pre-made DIN 8 cable assemblies.
S4 unit with full logic cassette deck and EQ. Testing unit with red LED backlighting. Front of preamp-only unit Volume control, tone and fader pots. These are NLA, but you can bring these back to life using Faderlube. Detail of headunit mainboard to front display control boar. Testing LED backlight LED Overall view of unit mainboard. Testing radio Tape mechanism from full-logic deck showing belt routing. Installed unit with red LED lighting. I would stick to orange to match you car's lighting and those colors are widely available. RCA to 1/4" quick-disconnect adapter. Switched it and here's the hum-free circuit. This is why I used a breadboard to mock things up. Using the same DIN8 cable assemblies from Digikey, the orange wire is audio signal ground and the brown wire is +12V. When either the cassette player or radio is on, either component supplies power to the preamp section and EQ via the DIN8 cable. One more thing, the power antenna is controlled via the on-off push-button volume control, even if a tape is playing. The cassette player will still run whet
Last edited by cluosborne; 10-13-20 at 11:24 AM.
Reason: One more thing.
Hi. Does anyone have a line (to existing thread) that shows the wiring for this radio? We have removed the aftermarket radio in our 90 FC Convertible and we have this unit, but no wiring harness in the back of the radio. I know the vehicle side wiring, but have been frustrated trying to determine the radio side wiring to match it up to. Any help appreciated. THanks.
03-19-12, 05:06 PM
