DIY - DVB-T Upgrade Cheap Option!
Hope you have all had a good xmas and new year!
As most of you know if you have the old analogue TV tuner in the UK its almost now 100% useless! and upgrading to the BMW hybrid version can be expensive if you can get hold of one!!!
I will explain here what I did to convert my old analogue tuner to digital.
This is my set-up as it stands:
The tuner I used was an Eonon V0012, it's a cheap chinese unit found on ebay from anything between £70 - 100, to be honest the quality is not bad, even when dissecting the unit out of curiosity I was surprised at the overall manufacturing quality and board layout.
Anyway anything will suffice, a more expensive Alpine unit would have been nice etc... depends on your budget.
Right, there are pros and cons to this setup. Pros being its a cheap alternative, you can listen to digital radio etc.... the con being the channels cannot be changed from the iDrive or steering wheel (yet!).
To perform this upgrade you MUST have the factory fitted analogue TV module in the boot! basically the TV module has a CVBS video output (yellow plug on many TV and DVD platers etc) this is easy, this signal is sent directly to the sat nav computer where it is scaled and converted to RGB and then sent to the control display in the dashboard.
The audio is a little more tricky! the E65 has the fibre optic MOST bus, all audio is converted to digital and split into packets and sent around the fibre loop until it reaches the ASK or Logic 7 amp where its extracted, converted back to analogue and blasted out of the speakers!
Below is a picture of the standard TV unit with the cover removed:
Most of the board is the power supply, MOST interface circuitry and a processor that controls the tuner module itself (vertical shielded box).
On teh rear of the board almost directly under the MOST bus interface circuit is a 14 pin SOIC marked PCM1801U. This is the IC that converts the analogue audio to digital.
The tuner itself only outputs MONO audio, therefore Left and Right channels need to be joined together, I simply joined both channels with resistors and connected to the 1uF capacitor on the board.
The 1uF cap is lifted from the PCB and placed on the little mod board and then linked back down to the pad that connects to pin 1 of the PCM1801U.
The grounds are also joined together and soldered to a common ground on the PCB.
The TV module now modified with 'aux' input. when 'VIDEO' is selected on the iDrive the audio from the TV module is now output through the car speakers.
Another tricky problem is powering the new tuner on and off without it interfering with the power management module in the boot!
I designed and built the circuit below:
Basically it has a permanent 12V from terminal 30 in the rear fuse box, the ACC line of the new tuner is switched on using a P-Channel mosfet, the gate of the mosfet is pulled high to switch it off and to GND to switch it on, unfortunately the opposite way we want! hence the need for another smaller N-Channel mosfet, this takes a signal from the power management unit (pin 18 of the 37 way connector) this input (to switch the tuner on and off) is switched high whenever the key is in the ignition.
A constant 12V is also fed to the tuner via terminal 30, there is negligible current draw on this input so the car will go to sleep as normal.
pictures of rear fuse box with the two extra fuses(top right) and the blue wire switching the power on and off to the new tuner.
Grounds connected to stud of comb connector:
Thats it really, if anyone wants schematics of how its wired then let me know, hope this may of be some use to someone!
very nice write up & work :thumbup:
Texas Instrument's datasheet on this IC shows it as a "SINGLE-ENDED ANALOG-INPUT 16-BIT STEREO ANALOG-TO-DIGITAL CONVERTER", with Pin 1 as the Left input channel and Pin 2 as the Right input channel. Did you try using Pin 2 using a 1uF capacitor to get Stereo sound?
I haven't thoroughly read the datasheet to determine if additional wiring or components would be necessary...
Nice write up! Might I recommend some hand lotion:eeps:
Thats correct the IC is indeed stereo, the IC has a LRCLK which toggles high and low and determines what channel is sampled and sent out as digital.
Pin 2 (right channel) is tied to GND on the board it would be possible to connect the right channel. The problem is the rest of the system is not configured to process any data from the right channel, the processor only accepts data converted from the left channel and puts this data on the MOST bus as left and right (duplicated).
I believe this is because the original tuner module only output multiplexed mono which is both channels in one with another carrier frequency, to convert this back to stereo this would have to be done before its processed by the PCM1801.
Its a shame, stereo would be great! however mono isnt that bad to be honest.
This is the schematic for the circuit that switches the tuner on and off.
It is connected to terminal 30 via a fuse, and the switch input is connected to the power module. The ACC is switched to 12V when the key is in the ignition.
Q2 is a P-Channel MOSFET, it can be anything with a capacity of 10 or so amps, a low on resistance is ideal. Q1 can be any small signal N-Channel MOSFET few hundred mA at most.
My goal is just to see if these analog TV/Video modules can be turned into an Aux Stereo / Video input. Your work is a great step in that direction.
Like your situation, in North America these analog tuners don't really pull in any stations.
Yes, kind of. There is an IC that is dedicated to maintaining the MOST bus interface. Its sole job is to receive data from units further up the chain, process any information it needs and then create the MOST bus data containing the digital audio.
The audio chip has two inputs, left and right. The chip needs to be controlled externally by a processor. The IC is designed such that when the LRCLK is low audio from the left is converted to digital, and when high audio from the right channel is converted to digital. This would happen very quickly.
The problem is the right channel has been intentionally pulled to GND with a resistor, this must mean that any information from the right channel will be ignored otherwise audio would only come out of the left speakers in the car.
It could therefore me assumed that the LRCLK could also be tied to one logic level as the system as a whole only processes left channel data from the IC. But.... That input goes off somewhere, it's a 4 layer board with power planes on layers 1 and 4 meaning you cannot visually trace the tracking.
I understand what you want to do, it may be worth looking at the factory DVD changer wiring, I'm 99% sure aux audio and video is routed through the video module. That may only be applicable for the 5drive tuner for rear entertainment. However the PCB looks to have provision for another two tuner modules like the 5drive. I may take the tuner apart and investigate the card more. It would then be a simple task of recoding the MMI to add DVD functionality.
Hope this helps
stuartjohn24, great job!
Could you please explain me how you connect video signal? Its connected to the nav or OEM TV tuner?
I already have the factory DVD Changer retrofitted into the car, using a VM5 ECE Tuner. The video does go into the TV/Video module, but audio is sent through MOST, just like the rest of the "Entertainment" modules. Attached is the EBA document - as always the wiring diagram is on the last page.
You can enable the DVD option on your MMI, but with the MMI being the master controller I expect it will "gray out" the DVD option with the DVD Changer hardware missing.
There is an AUX Video input on the TV/Tuner module according to WDS:
"In the case of PAL / SECAM 50 Hz, can be switched for NSTC to 60 Hz. For special solutions of BMW Individual"
TIS shows this as PIN 8 and 17, but only on a VM5 DRIVE (front and rear entertainment). This input may have been consumed when Night Vision came out.
How are you connecting the video output for this?
you say it's through the nav, do you have any further details on this?
Hi Rostman and richpu,
Sorry for late reply, Yes the CVBS video signal is fed directly into the Nav computer in the boot.
The video signal wire goes to pin 3 and the ground/screen goes to pin 11.
The connector is X1313 which is the 18 pin connector on the far right of the unit looking from the back.
Im not sure if anything else needs to be coded other than the MMI if you are just wanting to add a video input without fitting the full TV tuner etc....
Im looking at the possibility of interrupting the video source when the car is in reverse to add a reversing camera, this wouldn't be too difficult, its just finding the time to do it!
Hope this helps.
Thanks for your help on this.
I made the modification to the TV Tuner Module for sound and that works great. I have also a little DVB tuner from ebay and the video out works great.
I also did the VIM modification using NCSexpert as per this post
it works a treat.
hi stuart im new on here so il pm you.
I see you say you hacked in to pin 3 on the nav dvd player. What are you selection to get the video and audio to play on the mmi? Does you nav and video play at the same time. I am trying to send video to my rear screen with out the use of the dvd changer.
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