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MTCD - Swap Radio Module TDA7786 for TEF6686

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By marchnz, Senior Member on 20th July 2017, 11:21 PM
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Update 27/07 - did not improve the radio enough to recommend this modification/change.

Apparently the TEF6686 module has better performance than the TDA7786 - e.g. 7786 poor sensitivity, selectivity, multipath issues etc. My JY TDA7768 is terrible, even with an RF amp, so to find out if the TEF is any better, thought I would try and investigated swapping tuner modules. Reviewing the GS board I have as a spare part against my JY, I identified the modules are pin-for-pin compatible.

Sucessfully swapped the Radio module from a donor GS board containing a TEF6686 Module into my JY board originally containing a TDA7786. The GS board was quite difficult to unsolder the module, perhaps due to leadfree solder, fortunately the JY board was easy, the desolder wick readily desoldering the module.

As for results, I have bench tested and RDS, tuning, audio etc is OK, I am yet to test in the vehicle. Will update this thread with results.

See attached images. Note that the JY case had additional mounts that over time might short out against the non-ground PCB tracks, resulting in complete failure of the unit!

Welcoming any questions.
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21st July 2017, 04:05 PM |#2  
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Did the reception really improved?? And RDS AF fuction is working well with malaysyk V3 firmware?
22nd July 2017, 03:52 AM |#3  
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also interested in this outcome

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22nd July 2017, 04:00 AM |#4  
Hi,
The tef6686 appears marginally better, is more sensitive and appears to handle multipath better. Im not sure if I would call it out as a worthy upgrade just yet - need more time.
22nd July 2017, 04:08 AM |#5  
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wonder if it can be bought on its own.. seems like just the chip itself which is surfaced mounted on the riser card as pictured above.. so this would prove difficult to install

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22nd July 2017, 04:45 AM |#6  
Quote:
Originally Posted by stinger4321

wonder if it can be bought on its own.. seems like just the chip itself which is surfaced mounted on the riser card as pictured above.. so this would prove difficult to install

k

Ive seen a suitable module available on aliexpress that would need some modification to swap a couple of pins. That is the TEF6686-TDQ-230V-186 (10 pin) - a whole $6 bucks US.

http://s.aliexpress.com/QBfay
22nd July 2017, 06:32 AM |#7  
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Next week this module come to me , so in the next weekend I have time to swap.

https://www.aliexpress.com/store/pro...612.0.0.y1ZYeS
22nd July 2017, 09:36 PM |#8  
Quote:
Originally Posted by cupi1234

Next week this module come to me , so in the next weekend I have time to swap.

https://www.aliexpress.com/store/pro...612.0.0.y1ZYeS

That's great, don't forget these are not pin-pin identical and will have to figure out swapping pins. Search for the manufacturer PDF and check against the mtcd schematic. I'll upload the module PDF later today.
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24th July 2017, 08:38 AM |#9  
Hi, final thoughts - the upgrade in my experience was marginally better - not worth it!
24th July 2017, 10:37 AM |#10  
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Quote:
Originally Posted by marchnz

Hi, final thoughts - the upgrade in my experience was marginally better - not worth it!

could be something else in the implementation, not just the chip itself.
i have 2 boxes, one with 7786, the other with 6686 and the difference in reception is worlds apart. I mean even with the powered antenna not connected to 12V, i had no hiss on any station received.
7786 with powered antenna is just fine, don't get me wrong, but 6686 is better.
24th July 2017, 11:48 AM |#11  
Quote:
Originally Posted by zerozoneice

could be something else in the implementation, not just the chip itself.
i have 2 boxes, one with 7786, the other with 6686 and the difference in reception is worlds apart. I mean even with the powered antenna not connected to 12V, i had no hiss on any station received.
7786 with powered antenna is just fine, don't get me wrong, but 6686 is better.

I had thought about that but there's no difference in implementation I can see after comparing from schematic. Perhaps I had a 'good' 7786.
- MCU is latest HA
- Both modules are digitally controlled by MCU/i2c bus.
- same supply
- latest HA android 6.

There's really not much to it, 5volts, antenna connection, i2c comms and audio out. I get multipath noise/crackles from stations between 99 and 102mhz. Same between both tda and TEF.

Can you clarify what you mean by 'better'.
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