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Got the manual for the door woofer amp scanned. It is currently in .jpg format. All the foldouts were 2 pages max, so I didn't have to worry about a whole lot of distortion splicing them together. The bigger manuals are going to be another issue... I got a trial of photoshop to splice the foldouts together. I need to get some sort of pdf editor to put them together into an actual manual format instead of just a bunch of pictures. I'll wait until all the pictures are done, so I'm not paying for a bunch of subscriptions on software I rarely need.
Alright guys, here's an update. I just finished digitizing the manuals I have, now I need to host them somewhere for you guys. I digitized the manuals for the two different versions of the RX-7 CD players that I could find, as well as the manual for the door subwoofer amp. I also have 5 other digital manuals related to this project that I was able to purchase already digitized. The ones I downloaded were fairly low-res, but the ones I scanned, I wanted to have in color, and reasonably high resolution so you can follow the circuit diagrams better. I believe that has been accomplished as those files are far larger than the low res ones. I've gotta work tomorrow so it's not going to get done this weekend, but possibly the next. But for now, it's bedtime...
Nice progress, and thanks for the update. If you re looking for a way to send files, then wetransfer.com sends some pretty big files. You can use me for your test run - just let me know and I will send you my email address, cause I would love to have these schematics. Again, I would happily pay a reasonable fee for these. I could just paypal you costs associated with your time and work.
Sure thing. I did some double checking this evening. The ones I found online were pretty crappy, so I'm doing some editing to try to improve them just a hair, although it may just be a lipstick on a pig situation... I'm thinking on making an index file to list out what interactions I have found so far with the radios we have and putting them all in a zip or rar file. The index file can be updated as this project goes, so we can keep working together. I've got about $50 worth in the manuals when I totaled the receipts. By the time I'm finished, I'll probably have about another $20 in editing software subscriptions.
On a more repair related note, there is a guy selling a radio on ebay that has the correct laser assembly inside it, but its a cd player for an 88 mustang and he wants $400 for it and it looks rough... guess he knows what he has and can't be told otherwise. Really what I need most is access to parts. If they're used and still functional, that would work too...
One hopeful note, I was able to remove the lens and coil armature from the focus assembly of a laser with a broken suspension. I need to get some epoxy tomorrow for reattachment, but I have an intact suspension with a burnt out coil armature, so I'm hoping to be able to combine the two functional parts and put it in a sled that has good diodes... hopefully all those things go correctly. More updates as I can.
I did see a video thumbnail on youtube today about putting the bluetooth input on the tape deck (different car), so I need to give it a watch. Here's the link.
That guy certainly knows what's up. I think this will be the eventual route I take. What I did works, and maybe there is a way to get the CD player to stop skipping, but I think getting a cassette tape in there might be a better idea. Also, what I did required some external stuff, everything here is neatly contained in the factory head unit.
Very interested to see where you keep taking this!
I like that method he did in general, just with a couple of caveats. The first is that he has a lot more real estate inside that thing to put that additional board. Ours are pretty packed. Replacing the CD unit would free up a lot more room inside that thing. The second is that if you're like me and use a lot of Bluetooth, that's a lot of wear and tear on the tape deck that's already 30+ years old. Replacing the square bands weren't too bad, but did require a lot of scraping the formerly-rubber goo out of the gears and wheels. The wires for the small actuator motors were somewhat brittle though... I'd be careful of it. Not difficult, but requires a lot of patience. Would definitely be the cheapest and easiest if you could find a place to safely fit that board. It would better fit in the AE unit than the main stereo, but then you have to run a couple wires up to there... I just had an idea but I'll have to look into it.
I do think that a board like that would be included in the final build, I'm just not sure which way to go. As far as control goes, his just piggybacks off of the tape deck running on regular logic, so no control from the unit can influence the bluetooth. According to the wiring diagrams, the audio signal for the tape deck and CD deck meet before going into the pre-amp section. Its just about what set of controls we want to develop.
I finally have a zip file with the current collection of manuals and a brief introduction typed up to get folks started. I had to go back and re-edit the manuals I found online because the circuit diagrams were split up, and some of the pages were out of order and it was driving me bananas being out of format so I had to fix it. The zip file is about 380Mb, so we'll need to find a place to share it, maybe the wetransfer. As far as chipping in, I'll leave that option to you, the information will be available for all who wish to contribute. I might need a hot-air tool for some things, especially if there is a need to use surface-mounted components to squeeze circuits into small areas. That might help out a bit.
One thing I forgot to mention, I found the Sony Type 3 (4) CD tracks for adjusting the CD player. I didn't include them in the packet in case it got picked up in the transfer for DMCA stuff. If you are interested, you can either look for those tracks on the internet (I found someone hosting it for free), or I can send you a flashdrive or something.
I've been looking at how the main unit processor chips communicate with the CD unit processors. Still learning because I know absolutely nothing about the subject. There's a couple options to making this stuff work. One would be to replace the CD board outright and put in an emulator board. That would require knowing the commands that the two chips are sending each other as well as their orders of operations and building a module based on that. The other option is to instead make a module that spoofs the laser pickup head, motors and switches. This would preserve the original DAC, chips and synthesizer, and likely sound better.
Either way, I don't think I'll be able to get all the functionality I was envisioning. I started studying the CDX2 player and it looks like the only things that are controlled on the actual CD board are most of the motors, some switches, and the general digital to analog conversion. The CD board is kinda dumb in that it just reads the CD and follows commands of the main chip. The main cpu stores the CD info rather than the CD controller. This means you would have to manipulate the CD library information on the main chip... That would more likely require programming and replacing the CPU with one built for a new module. Kinda bummed... Gonna keep at it.
I no longer have the stock stereo, but I want to commend you on your hard work here. The stock stereo looks great and the extra functionality would be awesome. I still have mine in a box (but mine is the S4 model with no CD deck), so maybe one day I'll do something similar and reinstall it.
Alright, I know its been a while since I updated this. I had to get some other things done, so now I'm back on the stereo project here and there. Hopefully I can have something suitable so that once it warms up, I can get the car running.
Gonna see if the suspension swap on that lens worked for the CD player. I did some more looking and I really don't think there is a way to break into the CD unit part of things without someone far more skilled than I am, or a lot more time. If the CD player starts working with this swap, I'm just going to leave it and do the tape deck mod.
On the AE unit, I have been doing some enginerding. Earlier, I said I was having trouble with the one-button setup for the vert running the circuits for the coupe. There may need to be some more mixing and matching of components to try to get them to like each other. (I'm working off of the CRT-1196 manual). There are 2 resistors that look like they change the actual signal going into the filter block of the AE unit. On the Coupe, resistors 601, 602 are 15k while they are 10k for the vert. There is also one resistor, 551, in the power amp section that is 2.2k for the coupe and 2.7k for the vert. These resistors are in line with the feeds of their respective amplifiers.
As far as stuff on the amplifier board is concerned, the only other differences are related to the transistors that are controlled by the front panel switches. On the vert, there are two transistors, one for each channel, that seem to allow a bypass to a lower resistance. Why? I don't know. I'm learning as I go, and I only looked at this last night. On the coupe version, there are 4 transistor and resistor setups. Each button controls two of them. I have no idea what this would be doing.
There is a difference in how the buttons control the transistors though. On the coupe version, it looks like the transistors get full voltage to the gate when their respective buttons are "Off", whatever that means to the coupe guys (wish I could just find a coupe amp instead...). On the vert version, the transistors get a divided voltage/current (have to hook up a scope to it to watch) that controls both transistors at the same time when the switch is on "Mute". Its an opposite power state, but that shouldn't matter much. You can move those around pretty easily. Gonna look into this voltage divider business on the amp and see if that fixes the issue I was having.
I just got one of the bluetooth modules in that guy's video delivered, along with the tape adapter, and some 3mm bulbs to try to replace the burnt out ones.
As far as the bluetooth module goes, it's big. I'm going to have to do a decent amount of fitting to find a home for it. The board for it measures 1 1/4" x 2 3/16", with a thickness of 13/32" with components. You could slim it down to 9/32" by desoldering the two harness plugs on top and soldering the wires straight to the board. However, I'm going to have to do some wiggling to find a home for it. There is more room at the back than the front, but that might present another issue. The radio unit is metal on all sides and grounded, along with the circuit board in the front panel This might make talking to the unit a bit difficult. It does have a plug for an external bluetooth antenna, so that might need to be an option if I get to that point.
I ordered some 12mm square drive belts to try on small tape deck motors. I have just been using o-rings up until this point, but I will give these a try when they come in and see if they fit. The big belts for the tape deck can be found in the Amazon belt kits, but these little ones are not in those kits. If 12mm are still too big, I'll have to try again.
The bulbs I got in are the kind used more towards model trains, etc. Its a 3mm incandescent bulb, similar to the ones in the front panel. We shall see if they are vastly different or not. I did try an LED in that place, and it is worth noting that the leg wires for the LEDs are much thicker than those for the incandescent, so if you don't remove all of the solder, and install/remove the LED with heat applied, there is a possibility of damaging the vias on the circuitboard because they are drilled for the thinner bulb wires.
I tried to adjust the CD unit to spec after reinstalling the laser that I tried to fix. I found out my oscilloscope is picking up noise from somewhere in my house, I can't figure out where, but I'm pretty sure its from the mains power. When I turn on/off other things, it usually makes it worse. Gotta figure that out too...
small update for now, but I'm feeling ok and have made some progress.
The 12mm square bands seem to fit pretty well for the tape deck. The only place I was able to find any that size was on Ebay, and they were sold out of Florida. If someone reads this in the far-off future, your mileage may vary. They were pretty easy to put in. I'll get to see how well they work when I try out the tape deck.
On the Bluetooth side of things, I have been fiddling around with the bluetooth module. Seems pretty straightforward as far as components go. It does have audio input as well as output. On that note, I am going to try to find a decent microphone to hook up to it and see how it does calling. This lends to the possibility of a "handsfree" talking, aside from dialing and answering. There are two things I have noticed in reviews and elsewhere. The first is that this thing will likely need an external antenna as I previously stated. A lot of people were complaining about connection issues post-install, and probably for the reasons I stated previous. I am looking for a source for a suitable antenna. The second thing to note is that sometimes the connection may need to be rebooted by switching the chip off and on. The power source and switching will be dependent on the location of the board. If I put it in the main unit, I have more options, but less room. If I am able to put it in the AE unit, I have plenty of room, but fewer options. If it is placed in the AE unit, I also have to find access to the audio lanes, which could prove difficult. That's where I am at for now.
I've got one of those on the backburner. I'll probably try to work on it once I'm done with this project. See if you can't find a manual for it. I haven't been able to. It might take an email to Clarion to see if they can find an old copy. It would be good to add to the info pile.
I got to do some oscilloscope testing of the bluetooth module to see how to power it and what sort of output it has. I put together a basic voltage regulator circuit to drop 12v from my bench power supply to a 5v supply for the module. I saw online that supplying over 9v to the unit caused problems, so I'm trying to drop down to 5v before the unit, so it can pull power directly from the +ACC voltage. I don't want to put any additional stress on the stock circuits if I don't have to. It outputs about 3.3 to 3.5v with a 1khz test signal sent from my phone. There is still some noise my oscilloscope is picking up somewhere in my house, so I still need to find it. Probably a small cheapo power supply of some kind. I have a good idea for how to get 12v to the regulator circuit and to the module. I am still trying to figure out where to splice in the output wires. Still gotta do some measuring. I'm pretty sure they will solder in to the pickup head prior to the amp for that unit, but don't quote me on that yet. I also want to add in some transistor control to switch the regulator circuit I made for the bluetooth module on and off when the tape deck is selected. Thats all for now
Well fellas, I know its been a couple months that I haven't bugged you with radio stuff, but here's an update. I managed to pick up another radio/cd unit off ebay, this time for the coupe! I have the coupe amp now, and don't have to rely on my converted vert one (hopefully). However, I did plug this one in before I tried to open it up. The LCD was dead, so I have no idea whether this radio unit was taking commands or not. No sound output, and I had no way of knowing what station I was on. The lights in the front panel did work though, and the lettering is in much better shape than the two vert units I had. The CD unit did want to feed in, but the CD kept getting stuck halfway in, so I gotta figure out the feed issue first. No volume to speak of as well, probably corroded volume pots. I opened it up and lo and behold, the CD mechanism and circuit board are different variants from the manual! The gift that keeps on giving!... It does retain the some connectors to the main cpu as well as power and amp distribution. I checked the continuity through the coils in the laser assembly, and they seemed to be intact. I will try to figure out the feed issue and keep this circuit board, mechanism, and laser together. The laser is of the same series as the others.
On the mp3 side of things, I found a guy doing a build for a small arduino based mp3 player that plays off an SD card or bluetooth and can output digital or analog audio. My idea would be to try to interface this with the other boards with bad lasers if possible. Just found it. Got some studying to do on it. I also finished cleaning out the garage and plan on putting out some videos on how the S5 TII vacuum system works, as well as how to properly set your throttle body. Once the 4th of July is over, I should have a little bit more time to put into these projects. Have a good one guys, give me a heads up if you think of something.
Made some small progress on this project. The latest effort has been to get documentation on all the significant chips on the CD PCB board. I have datasheets, or at least information on all of the Sony chips.
Datasheets:
Sony CXA1082 - Servo Controller - IC 601
Sony CXD1135Q - Digital Signal Processor - IC 701 (In Japanese. Could use a translator)
Sony CXK5816M - CMOS Static Ram - IC 702
Sony CXA1081 - RF Amplifier - IC351 (partial information)
NEC uPD6355G - Digital/Analog Converter - IC 703
Mitsubishi M5454AL - Motor Driver - IC 754
I can't find any information on the Pioneer chips. These would consist of:
PWM driver - PA3023 - IC 651/652
CD Control - PD4136B - IC 751
Main CPU - PD4155B - IC 801
This Sony set of chips seemed to have been used across a wide variety of CD player manufacturers. My next step is to draw a simplified block diagram to route how they talk to each other, and see if I can figure out what format they use to talk. It would be useful to have information on the Pioneer specific chips. However, as Pioneer was the end user, we may be limited to the chip pinout in the repair manual. Its not too bad for the IC751 and IC801 chips because there is a pinout description. The two PWM drivers should have more documentation, but it probably got hidden along with everything else Pioneer had from that age.
If you guys get bored, I would appreciate any info you find on those Pioneer chips.
I'm sure you're getting tired of seeing this post come up, but I made some more progress on this project.
There are a couple of ways to go about implementing this audio mod. We are trying to work around damaged lasers and mechanical parts, so the two options I see are to emulate the laser, and provide feedback based on inputs from the various motor drivers, or replace the entire CD mechanism and circuitry with a custom board.
I looked into the first option and that looks like it would be a pain in the neck. I would have to make a virtual CD drive emulator, like daemontools or something, that responded to changes in the motor drive voltages. I would then have to produce a modulated rf signal to mimic the signal from the laser pickup diodes. That signal would need to contain the audio and subcode controls that tell the CD control chip where the disc is at, and what commands are coming from the disc. It would also involve reverse engineering the cd commands. I found a copy of the Sony Red Book standard for CDs, and let me tell you, it is very dense with information I know nothing about. In trying this configuration, it is almost guaranteed that you would be limited to 99 tracks, and 80 min of play time. These tracks would likely need to be set prior to the operation of the emulator, and need to stay static to reflect what the system controller records to memory. You would be guaranteed to be stuck with one virtual disc at a time and trying to add any bluetooth to it would complicate things further by desyncing the audio from the subcode. You would have to run both the virtual disc and the bluetooth in parallel. Just complicated... no...
The second option is the one I am pursuing further. It is much more simple to implement... if it works the way I think it will... This option is dependent on how the disc library is stored in memory. If the disc library is stored on the CD controller chip in memory, we should be golden. If not, it gets nasty quick. During typical operation, the main CPU runs the radio and tape operations. It can do both of these without the CD board and mechanism even connected. The question is, does the main cpu actually control the CD circuitry or is it the other way around? This is the question I need to figure out.
Most of the operation of the chips is a 5v system. This was built in the 80's and most electronics were 5v then, with 12v used for motor control operations. There are a couple strange 8v parts mentioned, but I don't see their relation with the mechanisms being that important as this option eliminates the motors and drive completely. To get audio out of the DAC, through the isolation filters, and dumped into the mix amp where the audio from the tape and radio seems like a fairly straightforward process. The DAC requires 3 input wires, in I2S format, which has been a standardized digital audio format since the 80s. It is a 16-bit x 2 channel signal that is easily converted to from many different file formats. Bluetooth to I2S is fairly easy and readily made on Youtube. There are 2 additional inputs for deemphasis and mute of the DAC and Isolation filters. These are controlled by the CD controller chip. The CD controller also controls the power for the other chips on the board as they are relegated to a separate 5v regulator. Getting audio out seems like the easiest side of things. The controls side is going to be a little more complicated. Both the main CPU and the CD controller chip share VDD at what I believe is 5v. They share 6 communications pins. I need to see how each communicate, one is simply the clock signal, just need to find the frequency, and where it is generated. There are a couple data I/O pins that share the same wire. I need to determine the functions of the others by looking up the terms used to describe them. The one that stuck out to me today as I was working on this was that the main CPU has a pin labeled AUX Input, and the CD controller has this labeled as an output. If it what I hope is correct, the main CPU could potentially go stupid and respond to commands from the CD controller and act as an intermediary between the front panel and the CD controller. If that is the case, and the library storage is on the CD control chip, then we should be able to get away with just about anything, so long as we limit the front panel to a max of 99 tracks before our new controller rolls over to Track 1 again.
So far, my design requires 4 analog pins, and 9 digital pins (I am sure some of these are analog too, I just don't know for sure) to whatever controller chip we want to use.
3 digital pins for the I2S protocol to run the DAC
2 analog pins for the deemphasis and isolation amp mute (I am not sure if these are required, as they are intended to remove noise induced from the optical pickup, correct me if you know better please)
1 analog pin for the +5v enable for DAC and Isolation Amp
1 analog pin for the Disc Set led on the front panel. It's driven directly from the CD controller. Could be another indicator of what functions are restricted to the CD controller
6 digital pins for communications from the PD4155 CPU to the PD4136 CD controller
The idea would be to print a custom pcb that can mount the controller chip we want to use, and have thru hole vias to re-use the connectors from the original board. There are 3 connectors to re-use: Audio out, Power, and Data. It would also be printed so that the original DAC and Isolation Amp Filter can be repurposed from the old board in the same electronic configuration.
The last thing to know is what communications are going on between the CPU and CD controller. I only have access to test mode because my units are all busted. I'm sure I could gain some insight with that, but theres still going to be some mystery because I won't be able to measure the normal communications under operation.
I do still really need video of a CD working as normal in the radio. From inserting a disc and playing, going through the different commands, skip, ff, rewind, back, and the others. Also, leaving the disc in and starting the cd player with a disc already in (resume), you get the idea. If one of you has some time and can get me a good quality video of it playing a cd in the different states, as well as what keys you are pushing, I would greatly appreciate it. Please and thank you,
I would imagine the answer to this is yes, but is having the CD audio important? Mine still functions, but I've hacked it to have the audio from the Bluetooth module. However, the CD mechanics still work.
@professionalpyroman Love the write up on this.. I happen to have one of these DEH-K4741 the bench with some fluctuating sound issues and thinking about a deoxit and maybe recap to start. Wondering if can you shared the documents you obtained? I can't even find a damn pin out for the main connector. And don't have the vehicle to try to pin it out. Love the methy jig for the cd alignment.... its what you gotta do sometimes.
Oh man, it's been a while since I've worked on this post. I do have some updates, though minimal. I've been really busy this last year, so now that I'm in a slow period, I'm trying to chug through some of my side projects. I have collected a few more datasheets, but there is one critical thing I can't find. There is a book printed by sony, its cover looks like the picture below. This has the data for all the CD player chips, a couple of which we are missing the majority of the information. It's a huge book, but if we could get ahold of one, or find one that someone could digitize, that would be a game changer. I have found full digital copies of a lot of other books, but this one has been driving me nuts.
Another thing I found is that the main sony chip configuration used in both the DEH-4141 and 4741 variants is the same as that of the TurboGrafx CD drive https://wiki.console5.com/wiki/Turbo_Grafx_CD-ROM_Drive. There are some efforts in that community to have optical drive emulation like what I'm trying to do, and I'm going to try to reach out to them this week and learn about how they've done some mods. I did find a guy that is advertising universal ODE circuit boards, but at $300 each, thats too cost prohibitive for us right now (or for me at least). I would imagine that they would be interested in the above Sony book as well. If we could get ahold of one of those, that would be a big deal. I don't know if we have any importing members that are able to hunt down such a thing, there's got to be a few copies in Japan. The last mention of this book I have seen on a US forum was a post from 20 years ago and he said it was too big to email, which at the time would have been correct. I sent him a message, but haven't heard back.
Thats all for now, let me know your thoughts, I'll try to stay on this project a little better.
I have downloaded all the books preserved on that site and am combing through them for info, even datasheets on later series DSP chips. It looks like Sony kept the same 80 pin flat pack die package for quite a while. I haven't compared the pinouts yet, bit if it matches up, I may just roll with the info in those datasheets. The book pictured above is the one that isn't on that list unfortunately. We are looking specifically for the CXD1135Q DSP chip in this book. There is a 6 page scan from the japanese version of this book that has about 5 pages of info, primarily just the pinout. I posted it here. I have a spreadsheet where I have typed out the google translated pinout into a table. The missing information is the command list and timing from the CPU. It probably also contains information on the RF amp chip, of which I haven't been able to find a legit datasheet, just stuff people have reposted online. Now that we know that the same DSP, Servo controller, and RF amp configuration has been used in different machines, with different CPUs to interface to, we can reasonably assume that configuration has some universal protocols. I do have a complete datasheet for the servo controller. It is a scan, but it has the timings and commands that come from the CPU. The servo controller and DSP share the same data lines. The commands listed in the servo controller datasheet list half of the CPU commands from $00-$7X, with "Higher instructions than $7X are codes for the CXD1135 and several outputs are obtained by connecting to the CXD1135 "SENS" pin."
If we found even a hardcopy of this book, I'd scan the entirety of it because it would be of use to a lot of people. There are a bunch of posts on the DIYAudio forum looking for this datasheet for the CXD1125,1130,1135 series, and all are in that book. There are links on that website to some Russian hosting sites that claim the full version, but those were posted 20 some years ago and are dead links to me.
Got a lead of a different kind. I haven't been able to verify it yet, but it looks like the IC751 CD controller chip, and the IC801 main unit controller chip, labeled PD4136B and PD4155B respectively, are both relabeled NEC 75108 microcontrollers. I am currently comparing the pinouts to see if this is a possibility. The 75108 microcontrollers were programmable by the end manufacturer. Although I haven't found any evidence of Pioneer using them specifically, Sanyo and other companies would buy these and program them for various uses. There is some documentation on timing and commands for these. I am looking to see if we can get the rom off of one of these, specifically the CD controller chip. If we can get that, that would make it possible to eliminate the vast majority of the CD player chips and replace all their functions with a microcontroller that feeds straight to the audio DAC as well as the main unit. It looks more promising than that Sony book showing up any time soon. I'll keep you guys posted
01-01-22, 02:23 PM
