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--- projects:yamaha_r840 [2025/10/23 20:12] – [iPod-30pin Dock] admin
+++ projects:yamaha_r840 [2025/12/01 07:53] (current) – admin
@@ Line 1: / Line 1: @@
-====== Yamaha MCR-840 ======
+~~META:
+title=Yamaha MCR-840
+description=Yamaha R-840 repair and hacking
+keywords=SEO, dokuwiki, disassembly, yamaha, R840, music, hack, hacking, audio, iPod, system connector, repair
+~~
+====== Yamaha Audio Amp/Receiver ======
+===== Yamaha MCR-840 =====
 Yamaha R840 is part of Micro Component System MCR-840 and comes with either CD-Player (MCR640), DVD-Player (MCR840) or BluRay-Player (MCR940). The players are connected via RCA but need a proprietary "System Connector" cable. The remote control is different for MCR640. \\
 The system comes with Yamaha NS-BP300 speakers in black or white which sound good. \\
@@ Line 7: / Line 14: @@
 {{:projects:yamaha:yamaha_mcr-840_micro_component_system.jpg?nolink&200|}}
-===== Repair & Service =====
+==== Repair & Service ====
 **Schematics / service manual**: \\
@@ Line 17: / Line 24: @@
 Read the block diagram from service manual: {{ :projects:yamaha:block-diagram.pdf |}} \\
+I have re-uploaded the necessary pages from service manual seen in hifi-forum threads for capacitor and resistor repair: {{ :projects:yamaha:yamaha-r840-repair.zip |}} \\
-==== Capacitor ====
+=== Capacitor ===
 The stereo receiver has a standby circuit, which is permanently powered and uses a film capacitor (C13 with 22nF, 630V). Due to aging and impulse spikes the capacitor dies, the yellow LED just blinks and the receiver does not turn on.
@@ Line 26: / Line 34: @@
 Replace with Polyester dielectric capacitor (MKT type), or better use one with polypropylene (MKP type). The voltage rating may also be higher than 630V. \\
-==== Resistors ====
+=== Resistors ===
 'Protection Mode' problem: \\
@@ Line 41: / Line 49: @@
 Probably more Yamaha systems can be repaired in that scheme. \\
-===== Disc Player manual eject =====
+==== Remote control ====
+There is nothing much to say. It is a simple iR remote control. The main IC is marked "2428662 03160". \\
+iR codes for R840 can be found on page 80/150 of service manual (next to remote control schematic). \\
+Here is an unspectacular insight: \\
+{{:projects:yamaha:rc1.jpg?125|}}
+{{:projects:yamaha:rc2.jpg?200|}} \\
+I have taken the pictures so you can see at which positions the holding clips are - don't forget about the single screw in the battery compartment.
+The buttons and their layout of remote control for DVD and BD versions differ slightly. \\
+==== Disc Player manual eject ====
 The players only turn on with system connector plugged into R840 amp (see [[projects:yamaha_r840#the_round_one|below how to simulate system connector]]). \\
 To eject disc from player without power, the manual says to slide a flat head screwdriver in the slot at the bottom. \\
@@ Line 48: / Line 64: @@
-===== System Connector =====
+==== System Connector ====
-==== the round one ====
+=== the round one ===
-The system connector is used for a connected disc player. It enables the RCA-input for the player and also transfers signals like power-toggle. \\
+The system connector is used for a connected disc player. It enables the RCA-input for the player and also transfers signals like power-toggle and remote control signals. \\
 It uses proprietary 8‑pin DIN connector (find the cable under name "MINI DIN 8-PIN MD8"). \\
@@ Line 67: / Line 83: @@
-=== communication signal ===
+MD8 "ZP512100" cable is not only used by MCR-840 but also various other systems like MCS1330 (R1330 + CD1330). As I do not own anything else but R840, I cannot say if other devices use the same protocol or even pinout! Always check yourself before. \\
-BAUD is 9600, 8bits, 1start+1stop bit, no parity; \\
-First two bytes are always 0xFF 0x55 (at least with CD-player) \\
+== communication signal ==
+Even though lines are called MISO and MOSI in service manual, the communication is UART tx/rx. BAUD is 9600, 8bits, 1start+1stop bit, no parity, LSB first; \\
+First two bytes are always 0xFF 0x55. \\
 Last byte is checksum = (~(sum(bytes_except_checksum) & 0xFF)) & 0xFF \\
 For the bytes in between, see source code. \\
 #TODO unlocking CD-Player RCA input + remote controls + USB\\
+#TODO upload pulseview logic analyzer snippets \\
+=== the flat one: writing port ===
-==== the flat one: writing port ====
+This is just an FYI, IMO we cannot do anything useful with the port. \\
+Yamaha devices use a so called "writing port", a flat cable, e.g. to flash ucom via RS232-adapter. It is known for updating firmware over PC software (which we don't have). \\
-Yamaha devices use a so called "writing port", a flat cable, e.g. for flash ucom via RS232-adapter. It is known for updating firmware over PC software (which we don't have). \\
-R840 uses Renesas M16C MCU. Service manual states to use FlashSta.exe (which we don't have, neither R840_xxx.mot + R840_xxx.id firmware), FYI see [[https://www.renesas.com/en/document/mat/m16c-flash-starter-m3a-0806-users-manual?srsltid=AfmBOoouDn1Ckenn0l-1YUgHz2BwZHPVGnbNhIjZUAa85k5-iwqpdRbM|Renesas M16C flashing guide]]. If you still want to look into flashing M16C MCU go to
+R840 uses Renesas M16C/64 R5F3640DNFA MCU. Service manual states to use FlashSta.exe (which we don't have, neither R840_xxx.mot + R840_xxx.id firmware), FYI see [[https://www.renesas.com/en/document/mat/m16c-flash-starter-m3a-0806-users-manual?srsltid=AfmBOoouDn1Ckenn0l-1YUgHz2BwZHPVGnbNhIjZUAa85k5-iwqpdRbM|Renesas M16C flashing guide]]. If you still want to look into flashing M16C MCU go to
 [[http://www.m16c-flasher.de/]] or [[https://m16c.mikrokopter.de/]]. There is also an OSS flasher on github [[https://github.com/truhy/m16c-flasher]] fixing some of the problems. \\
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-====== iPod-30pin Dock ======
+===== iPod-30pin Dock =====
 Make sure the input on the iPod dock (like Bluetooth adapter) is pre-amplified - (the cheap adapters are commonly not)! \\
@@ Line 109: / Line 128: @@
 [[http://www.ipodlinux.org/Apple_Accessory_Protocol/]] \\
 [[https://github.com/xtensa/PodEmu/tree/master|xtensa/PodEmu: Android application that emulates iPod to use together with old 30-pins iPod serial interface]] \\
+[[https://xdaforums.com/t/app-3-0-podemu-connect-android-to-30pin-ipod-docking-station-or-car.3234840/|PodEmu on XDA]] \\
 [[https://github.com/xtensa/oap|xtensa/oap: Implementation of iPod serial communication protocol used in old 30-pin iPod interfaces]] \\
 [[https://github.com/oandrew/ipod-gadget|oandrew/ipod-gadget: iPod usb gadget for audio playback]] \\
@@ Line 117: / Line 137: @@
 #TODO add custom PCB for iPod dock replacement \\
-====== other Yamaha ======
+===== other Yamaha =====
 **RTFM:** [[projects:start#links|See the links to search for service manuals, schematics and docs]] \\
@@ Line 123: / Line 143: @@
 [[http://www.hifi-forum.de/viewthread-220-9029.html|hifi-forum.de Yamaha R-S300 repair]] \\
-===== USB iPod iAP =====
+==== USB iPod iAP ====
 Receivers with USB can use its iPod input if available. RC and CoverArt possible. \\
 Note: [[https://github.com/pamaury/rockbox/blob/master/apps/iap.c|RockBox-Player supports iAP]] \\
@@ Line 135: / Line 155: @@
 FYI: Texas Instruments’ CC256x Bluetooth modules have optional software add-ons for iAP support in the module / stack, so there is no need to implement the full protocol. \\
-===== Yamaha Loudness =====
+==== Yamaha Loudness ====
+Loudness compensation is used to maintain a balanced sound at different volume levels. At low listening volume levels, the bass drivers need to produce more sound pressure to be perceived at the same level as the mid and high frequencies.
+See a collection of schematics for loudness circuits here: [[http://www.hifi-forum.de/viewthread-71-12517.html]] \\
+{{:projects:yamaha:loudness-schaltung-yamaha.png?direct&200|}} \\
-#TODO upload loudness schematics \\
 #TODO software implementation of loudness \\
 #auto-volume level + auto-level loudness curve \\
 #add dynamic range compression \\
-===== other interconnections =====
+==== other interconnections ====
 === RS232 example projects ===
@@ Line 151: / Line 175: @@
 - [[https://github.com/akentner/yamaha-avr2mqtt]] rs232 with nodes.js \\
-==== system connector: the audio jack one ====
+=== system connector: the audio jack one ===
 Yamaha Soundbars use an audio jack as "system conector". It is a control voltage which can also be used to to switch a relais ~9-12V, consider using DC-DC isolated converter
 [[https://www.youtube.com/watch?v=KfUnEoQaNIs]] \\
-==== http / net ====
+=== http / net ===
 [[https://github.com/honnel/yamaha-commands]] http API \\
 [[https://github.com/Raynes/rxvc]] \\
@@ Line 168: / Line 192: @@
 [[https://github.com/coffeegreg/YTuner|YTuner ]] and [[https://github.com/milaq/YCast|YCast]] replace vTuner internet radio service for AVRs \\
-==== MusicCast ====
+=== MusicCast ===
 [[https://flows.nodered.org/node/node-red-contrib-musiccast|node red musiccast]] \\
 [[https://flows.nodered.org/node/node-red-contrib-yamaha-yxc|node red YXC]] \\
@@ Line 179: / Line 203: @@
 #TODO: bt-audio-sync force (aka MarantzNR) \\
-==== iR codes ====
+=== iR codes ===
-iR codes for R840 can be found on page 80/150 of service manual (next to remote control schematic). \\
 [[https://github.com/theCstokes/YamahaRemote/blob/master/IR_RX-V667-3067_rev0.0_Full.xls|yamaha V667 etc iR codes]] \\
-====== Related ======
+===== Related =====
 #TODO: Onkyo,Marantz,Denon system connector \\
 Consider using [[disassembled_devices:chinese_bt_fm-transmitter|Bluetooth to AUX and FM transmitter]] adapters to add wireless audio to your system. There are cassettes with line-in and even bluetooth too.\\