[Android Head-Units] Ced495:
Hi, I got a "REAKOSOUND" 9" head unit for my 2005 Citroen C4 Coupe, it has "android 10" or an imitation of it. I have no sound coming from the device (tried Youtube, radio, music app, and others. I manly want the main radio cable connection for sound, not RCA although I have tested the RCA connections which have no sound either.

What I tried:

- Reconnected wires multiple times

- Hard reset more than 3 times

- Seller provided "update" that did not change anything

- Tried an RCA speaker into RCA "Aux R Out" - no sound at all (Speaker from a 5.1 PC speaker set)

- Oscilloscope measured from the CANBUS/radio harnes from one speaker line coming out the head unit: 60Hz sine wave less than a millivolt, think that means no sound coming out the Head unit output.

- Tried all avaliable CAN Type options for citroen, steering wheel buttons work with all of them, no sound with any of them.

- Volume has been set to max "40 units".

- Original radio still works.

- Tried to look for some apps on google play that may control sound output, found only one, did not do anything.

- Tried all the apps: Radio, Music app, BT music, Aux mode, Spotify, Youtube, phone call (mic works) - no sound output from any app.

- Canbus works, the steering wheel buttons work and travel distance data is being transmitted to the head unit.

- Tried asking for OS update files from other Ali sellers, all refused to share (not compatible and such).

What I noticed:

- All the Citroen Canbus models in the head unit settings have 2008-2015 models, the ad said compatible with 2004-2008 car models - maybe the Canbus is incorrect for my car (I have Raise PSA-RZ-15)?

- There is no AMP wire coming from the cars side.

- There are no audio settings in the Head unit, Only an equalizer and a balance setting front to back and left to right, that's it. Other head units seem to have more options in the OS.

My Questions:

1. Should audio work without CANBUS?

2. If there is an amp in my car and it communicates with CANBUS, can I turn it on without canbus? (I have not seen an AMP wire in my car - nothing blue with a white stripe or similar)

3. Does anyone have any suggestions what to try to get any sound?

4. Are there any other car androids I could install and test?

a. (EDIT: I found this post on XDA, and this post, and this post, as far as I understand there is an MCU and a MTCD, one of them carries android the other is like bios that bridges the car system to the android, in my case, the sound issue could be from either of them)

5. If it's not android, what hardware should I check? I am decent with soldering and similar electronics, just Head Units are new to me.

Device info that I could find:

Brand: REAKOSOUND

CANBOXVER: Raise(FD) PSA-RZ-15

CAN Type Selected: Citroen - C4 quatre - [2016/NOW(1Gen)] - [16~Now(Overseas)] {11-2-1-2-1}

Origin: China - AliExpress (Store Link)

Other: "Made For Citroen C4 2004-2009", YouTube video tutorial with visually similar unit HERE.

Display: 9" (1024*600)

Max Ext mem: 32GB

ROM: 32GB

RAM: 2GB

OS: Android (10)

Connections: GPS, BT, WiFi, USB, RCA, CANBUS/radio harness.

Info from HU screen under System Settings:

APPVER: K2001N_NWD_S2... ...H4F9.01

Platform VER: K20N-2020/08/01... ...1.00_R

MCUVER: V4.1-FF01-20210311-A02-CAN0000-00-00-DVD00000000-00

BTVER: NWD829_V2.0/...