Morning Folks!
I hope I'm in the right section for posting this. I have a Pioneer DEH-K4141zm head unit for an old RX7. I have been able to restore all of it to great working condition except the CD player portion. The laser assemblies in these units were all built around '87 or '88 and the suspensions on all of them have been corroded beyond repair. I have purchased 2 additional head units, both cd sections no longer function and replacements are unavailable.
My objective is to build a device that interfaces with the DAC and CD control, or replaces the CD unit circuit board, that I can play bluetooth music over the head unit. The Digital Signal Processor is a Sony CXD1135q and the servo control is a Sony CXA1082AQ. I found an old post on here that talks about using these chips, but have been unable to get ahold of the posters to find more information and the thread is locked. It says their profiles are unavailable. Here is the link: https://www.diyaudio.com/community/threads/cxd1125q-and-cxd1135q-spdif-output-mod.317359/. I know what these guys are trying to do is a little bit different, I'm just wanting to see if they would have any input or possible direction for me to get started.
Here is a block diagram of the CD player from the service manual. There are also wiring diagrams, but the block diagram shows the general layout of the CD player circuit board.
I am thinking that my options are to either A) to build something that feeds in a spoofed rf signal of a cd image, and keep the servo controller and DSP setup, or B) make something to replace the PD4136B CD control chip and feed the DAC directly. This is going to be quite an undertaking since I am not an electrical engineer by trade.
The DAC receives a 2-channel x 88.2khz I2S format signal from the DSP, CXD1135Q. I'm still learning how these formats work, but for now, it has the 3 wires that I2S needs. It also has a couple other L/R inputs that the DSP controls, so I'll have to do some research on them.
I have found datasheets on all of the chips shown in this block diagram, except for the Pioneer PD4136B controller chip. I have no idea where I would find such a thing.
Anyways, this is a long first post. If any of you guys know about this chipset and can educate me on them, I'd be grateful. If you know the other guys in the cited post, and can steer them in this direction for comment, that would be great too.
Thank you and have a great day
I hope I'm in the right section for posting this. I have a Pioneer DEH-K4141zm head unit for an old RX7. I have been able to restore all of it to great working condition except the CD player portion. The laser assemblies in these units were all built around '87 or '88 and the suspensions on all of them have been corroded beyond repair. I have purchased 2 additional head units, both cd sections no longer function and replacements are unavailable.
My objective is to build a device that interfaces with the DAC and CD control, or replaces the CD unit circuit board, that I can play bluetooth music over the head unit. The Digital Signal Processor is a Sony CXD1135q and the servo control is a Sony CXA1082AQ. I found an old post on here that talks about using these chips, but have been unable to get ahold of the posters to find more information and the thread is locked. It says their profiles are unavailable. Here is the link: https://www.diyaudio.com/community/threads/cxd1125q-and-cxd1135q-spdif-output-mod.317359/. I know what these guys are trying to do is a little bit different, I'm just wanting to see if they would have any input or possible direction for me to get started.
Here is a block diagram of the CD player from the service manual. There are also wiring diagrams, but the block diagram shows the general layout of the CD player circuit board.
I am thinking that my options are to either A) to build something that feeds in a spoofed rf signal of a cd image, and keep the servo controller and DSP setup, or B) make something to replace the PD4136B CD control chip and feed the DAC directly. This is going to be quite an undertaking since I am not an electrical engineer by trade.
The DAC receives a 2-channel x 88.2khz I2S format signal from the DSP, CXD1135Q. I'm still learning how these formats work, but for now, it has the 3 wires that I2S needs. It also has a couple other L/R inputs that the DSP controls, so I'll have to do some research on them.
I have found datasheets on all of the chips shown in this block diagram, except for the Pioneer PD4136B controller chip. I have no idea where I would find such a thing.
Anyways, this is a long first post. If any of you guys know about this chipset and can educate me on them, I'd be grateful. If you know the other guys in the cited post, and can steer them in this direction for comment, that would be great too.
Thank you and have a great day
I would like to hack the cd portion so that I can have the functionality that comes with the CD player, like pause, ff, etc. I think that would lend itself to using bluetooth or sd card playback.
Sorry for the delay on replying. I have made some progress on this. I do think replacing the cd portion as a whole is the more viable option. I suppose the next set of questions for you guys would be relating to hooking up the DAC and the isolation filters behind it. As it sits in the current CD player, DAC has 3 inputs for the I2S audio, and 2 inputs for L/R channel sample and hold. Do you guys know when/how the sample and hold lines would be used, and how that works?
The second part would be regarding the isolation amp behind the DAC. It has 2 additional inputs, Deemphasis and Mute. Do you guys know how these are used, and if they would be needed if I send I2S audio to the DAC from something like an ESP32 chip?
I have attached a picture of the circuit diagram of this portion with highlights on the lines in question. Thank you for your time.
Sorry for the delay on replying. I have made some progress on this. I do think replacing the cd portion as a whole is the more viable option. I suppose the next set of questions for you guys would be relating to hooking up the DAC and the isolation filters behind it. As it sits in the current CD player, DAC has 3 inputs for the I2S audio, and 2 inputs for L/R channel sample and hold. Do you guys know when/how the sample and hold lines would be used, and how that works?
The second part would be regarding the isolation amp behind the DAC. It has 2 additional inputs, Deemphasis and Mute. Do you guys know how these are used, and if they would be needed if I send I2S audio to the DAC from something like an ESP32 chip?
I have attached a picture of the circuit diagram of this portion with highlights on the lines in question. Thank you for your time.