Replacing PCM3.1 with Erisin Android head unit DIY

11016 Views 224 Replies 21 Participants Last post by Cayman Ed, 2 d ago

T-Design

Discussion Starter · 3 mo ago (Edited)

(EDIT: basic installation instructions and short review: Outstanding Tech Contribution! - Replacing PCM3.1 with... )

I have an absolutely useless PCM3.1 in my 981S, and it was depressing from the get go. Every winter during my Boxster's hibernation I wanted to throw that pathetic POS PCM into the trash and replace with something nice, but every time I checked there were no units that would tick every box in my virtual checklist for ideal unit.

Well, when I checked this year - it looks like there is finally a unit, that on paper does absolutely everything I wanted. The biggest requirements

Navigation and music library without phone
wireless Android auto
wifi internet + movies
mechanical knobs
perfect fit with matching bezel

So no matter how busy I am, I decided it's time to stop being lazy, and bring my otherwise perfect Boxster into modern times.
Here's the link in case somebody want to follow... or to lead

www.erisin.com

Erisin ES8559C 7" IPS Android 11.0 Car Multimedia Wireless CarPlay Android Auto Radio For Porsche Cayman/Boxster/718/911/981/997 GPS DSP 4G SIM Card

Octa Core, 2*A75+6*A55 64-bit 1820MHz CPU, 4G+64G, Wireless Apple CarPlay and Android Auto, TDA7851L with DSP Amplifier, IPS, 4G Module for Internet, Split Screen

www.erisin.com

I did not see manual, and have absolutely no idea how hard it will be to install, but how hard can it be, right?
DIY to follow

Output device Communication Device Font Gesture Gadget

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anekdotos

· #201 · 17 d ago

deilenberger said:
Congratulations on a Technical Excellence Award!

Thank you!

I've got a few more bits of media for you all:

Boot Logos (PCM silhouettes & more - appropriately named and scaled)
- How to use
Boot Animations (PCM silhouettes & more - video files are previews, zip files are the actual animation)
- How to use
Wallpapers (PCM silhouettes & more - same files as my previous post, just renamed to represent the cars)

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Zoomby_U

· #202 · 17 d ago

3

Got my new wiring harness extension all wired up ... speakers into pre-out RCA's and cut the Canbus low line and added quick connectors. Highly doubt this is going to make any difference without some sort of line filter ... but worth a shot.

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anekdotos

· #203 · 17 d ago

@Zoomby_U Just wired mine up. Still have noise. Tried the DC filter as well. Still noise. Starting to agree that the source is likely noise introduced in the canbus. Would be really nice if we could just wire it up without canbus…

Cayman Ed

· #204 · 17 d ago

How about the relay switch click noise? Did your new harness adapter solved it? Bummer that your static/hiss noise is still there. Looks like it's not compatible with the OEM ASK amplifier.

Zoomby_U

· #205 · 17 d ago

Same here and sadly the same result, though the static seems slightly different and not quite as loud with the extension harness. Also tried with Canbus low disconnected and connected with no difference. Honestly with the car started I can't really hear the static anyways ... so I suspect I'll just live with it for now. The only other thing to try is attenuators on the pre-outs but I doubt that would really help tbh.

anekdotos said:
@Zoomby_U Just wired mine up. Still have noise. Tried the DC filter as well. Still noise. Starting to agree that the source is likely noise introduced in the canbus. Would be really nice if we could just wire it up without canbus…

anekdotos

· #206 · 17 d ago

Yeah unfortunately I even tried shorting the CAN Low to ground as I read that could improve it with no luck. Like you I also noticed that the noise is slightly different, and don't notice it when the engine is on (just drowned out tbh).

Will still keep poking. Once I get my CANBUS USB debugger Ill try to power it on without the canbus connected on the car and see if the noise is still there. Just to confirm whether or not it is in fact the can line.

Reactions: 1

Zoomby_U

· #207 · 15 d ago

I ordered some ferrite beads to put on the 12V power cable to see if it helps at all ... can also throw it on the Canbus, RCA line out and antenna cables for fun

https://a.co/d/gprZdYx

Cayman Ed

· #208 · 15 d ago (Edited)

If cutting the Canbus L wire does not work, you can try ground loop noise isolator on the RCA line level output if using gain attenuator does not also work.

Zoomby_U

· #209 · 14 d ago

Tried it on multiple cables and no change

Guess I'll have to embrace the static

Zoomby_U said:
I ordered some ferrite beads to put on the 12V power cable to see if it helps at all ... can also throw it on the Canbus, RCA line out and antenna cables for fun

https://a.co/d/gprZdYx

deilenberger

· #210 · 14 d ago

Zoomby_U said:
Tried it on multiple cables and no change Guess I'll have to embrace the static

I'm curious - the static - there when the engine isn't running? Engine speed related?

Zoomby_U

· #211 · 14 d ago

Yes static comes on with just the key in the ignition (not in on position) ... starts shortly after the head unit boots. Static doesn't change volume in any circumstance ... static does stop when you turn off the unit (even when the car is on).

deilenberger said:
I'm curious - the static - there when the engine isn't running? Engine speed related?

deilenberger

· #212 · 14 d ago

I would then suspect the unit itself having a noisy amplifier stage somewhere. On the one I'm playing with over on the 987 forum, I can sometimes swear I hear tiny voices - talking about things when I power it up and don't have anything playing. It's really weird, can't quite make out what's being said, but one women's voice stands out. And it's REALLY quiet. As soon as I start anything playing the ghost talkers retreat into wherever they live in the electronics.

Cayman Ed

· #213 · 14 d ago

This is really puzzling for users with ASK amp. I have an aftermarket (Alpine) amp to power my subwoofer. Input is from the SUB line level RCA out of the Erisin HU and I don't hear any noise, hiss, static when key fob is inserted except for the relay switch click that occurs every 10 seconds. This relay switch click goes away when Ignition is ON position. Other than this, I am happy.

deilenberger

· #214 · 13 d ago

My only thought on this is - did the ASK amp use CANBUS to control the volume, rather than controlling the output signal from the headunit? That's how the Bose system works..

In that case - it wouldn't surprise me if at maximum gain, especially with no signal passing through the amplifier that you'd hear some noise (aka static.) The designer's of the amp - in this case - wouldn't expect that the user would NEVER turn the gain up that high on the amp, and even if they did - the volume of the audio coming out of the amp would drown out the background noise. There is a term for this - Signal to Noise - and numbers that quantify this for amplifiers.

If the amp is turned up near max - with no signal going to it it's not a huge surprise that you hear static..

The output stage from the headunit may have a bit of noise in it, which amplified at full volume by the ASK amp might be noticeable when no audio signal is being passed through the amp. Or the signal-to-noise ratio of the ASK amp may not be that great, but the noise would be unnoticeable when used with the normal headunit since the amplifier gain would never be turned up that high.

In other words - nothing to be done about it except ignore it just like I've learned to ignore the little people having phone conversations in my headunit..

I can't hear them when music is playing - so it's no big deal.

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Zoomby_U

· #215 · 13 d ago

Agreed ... interesting thing is I tried another Android direct plug and play unit and it had even more static and feedback than the Erisin. It's definitely something with the OEM amp not playing nice with a new head unit.

deilenberger said:
My only thought on this is - did the ASK amp use CANBUS to control the volume, rather than controlling the output signal from the headunit? That's how the Bose system works..

In that case - it wouldn't surprise me if at maximum gain, especially with no signal passing through the amplifier that you'd hear some noise (aka static.) The designer's of the amp - in this case - wouldn't expect that the user would NEVER turn the gain up that high on the amp, and even if they did - the volume of the audio coming out of the amp would drown out the background noise. There is a term for this - Signal to Noise - and numbers that quantify this for amplifiers.

If the amp is turned up near max - with no signal going to it it's not a huge surprise that you hear static..

The output stage from the headunit may have a bit of noise in it, which amplified at full volume by the ASK amp might be noticeable when no audio signal is being passed through the amp. Or the signal-to-noise ratio of the ASK amp may not be that great, but the noise would be unnoticeable when used with the normal headunit since the amplifier gain would never be turned up that high.

In other words - nothing to be done about it except ignore it just like I've learned to ignore the little people having phone conversations in my headunit.. I can't hear them when music is playing - so it's no big deal.

anekdotos

· #216 · 13 d ago (Edited)

Okay some more info. I don’t think it’s the CANBUS. Unit will power on if only one of the two canbus lines are connected (doesn’t matter which). After boot, I removed the connection from both canbus lines. The unit stayed on and the noise was still there. ~~I believe now that the only way the noise could get into the system is via ground or VCC.~~

Edit: Sorry, noise could theoretically be coming through the Amp On / Control pin in the Quadlock. Interestingly I actually measured the voltage on that pin.

Amp On: 0.013V - 0.015V (fluctuating)
Amp Off: 0.010V

Maybe the noise is coming from the Amp control wire? I also thought the control wire was supposed to supply 12V when on? I would like to try to manually cause the amp to turn on to bypass the unit to see if that rules out the amp control wire.

Reactions: 1

Cayman Ed

· #217 · 13 d ago

The wire #3 (blue) in harness A is the amp power ON. Maybe this is a cleaner signal than that from the quad lock harness?

Midnight Blue

· #218 · 13 d ago

This thread is so above my head but I'm really enjoying following it!

Zoomby_U

· #219 · 12 d ago

Interesting ... I wonder what happens if you cut the amp cable

or maybe I'll try throwing a ferrite bead on it to see if it changes anything. I do agree, it does seem like it's something the head unit it doing during its power on cycle with the amp trigger being one of them. I think it just sends a signal for the amp to wake up and doesn't actually provide any real voltage, just a change in voltage. If we do cut it, wouldn't the speaker inputs cause the amp to wake up anyways?

anekdotos said:
Okay some more info. I don’t think it’s the CANBUS. Unit will power on if only one of the two canbus lines are connected (doesn’t matter which). After boot, I removed the connection from both canbus lines. The unit stayed on and the noise was still there. ~~I believe now that the only way the noise could get into the system is via ground or VCC.~~

Edit: Sorry, noise could theoretically be coming through the Amp On / Control pin in the Quadlock. Interestingly I actually measured the voltage on that pin.

Amp On: 0.013V - 0.015V (fluctuating)

Amp Off: 0.010V

Maybe the noise is coming from the Amp control wire? I also thought the control wire was supposed to supply 12V when on? I would like to try to manually cause the amp to turn on to bypass the unit to see if that rules out the amp control wire.

bob_5045

· #220 · 7 d ago (Edited)

This is the fiber optic cable on my 2016 cayman with cdr31 and bose, i cannot make it work with the erisin fiber optic decoder... doesnt fit. This cable will plug perfectly into back of the erisin headunit, but that isnt supposed to work, and doesnt produce sound

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