Advice for HDMI users

Discussion about displays and related hardware including MiSTer filters and video settings.
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keith.f.kelly
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

Well, it turns out there's at least one more HDMI pin that most be lifted to cure all compatibility issues with other equipment. I brought my MiSTer along to my parents' place and connected it to their TV via HDMI, and even with pins 13 and 15 lifted, having the MiSTer hooked up prevents their Sony BluRay player from powering on! I have to unplug the MiSTer's HDMI port from the TV to get their BluRay player to work at all. I suspect it's due to one of the other pins I cited in my earlier posts, but I don't have my usual tools and stuff with me here to identify which one is to blame.
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Re: Advice for HDMI users

Unread post by Yim »

I’m not sure if this is the same problem, but I have more HDMI devices than ports on my TV, so I’m using a switch box. The problem is that if the MiSTer is connected to the box none of the other inputs will give a picture unless the MiSTer is turned on. I’ve tried two different switch boxes, same problem with both. Has anyone else had this problem, and if so were you able to fix it with a CEC-less adapter? Or any other method?

If I plug the MiSTer directly into the TV I have no problem, but I’m trying to get all my gadgets on the switcher so my family don’t have to fiddle with it for the devices they use.
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Re: Advice for HDMI users

Unread post by Yim »

Further to the above, I had a look at the inside of my hdmi switchbox:

s3m4Z8S.jpg
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It’s a Simplecom CM340 mechanical switch, and although the list price on the page I’ve linked to is fifty Australian dollars I paid less than half of that. I bought it when my first switch box, a digital one, didn’t work properly with the MiSTer. I thought being a mechanical switch it would break all the connections of the inputs not in use and so stop any interference. And it almost does! There are twelve three pin switches per input, each going to one of the pins of the HDMI socket as I’ve marked in the image. Five of the pins all join to a common ground, pin 14 doesn’t connect to anything so far as I can tell, and all the pin 18s are joined together (even the one second from the top that doesn’t look like it’s connected - I checked it with my multimeter). If an input is set to on, then the output socket (top of image) is connected to it. If it’s off, then the signal is bypassed to the next input (via the vertical trace lines running between switch banks).

My problem I think is due to the common +5v line (pin 18). I tried plugging in the just the MiSTer to the switch box without turning it on, and I found I was getting continuity between +5v and ground. I don’t know much about electronics but that doesn’t seem right. Not sure if all de10s do this or if there’s a problem with mine. Anyways, I cut the trace for pin 18 leading to input 1 (bottom of image). This reversed my problem: instead of only getting a picture on other inputs when the MiSTer is on, I only get a picture from the MiSTer when something else is on. I think what’s happening is my TV is using the +5v pin to identify whether there’s a signal or not. Because the de10 connects +5v to ground when it’s off, it was draining the signal from the other devices making the TV think they were off. Now that I’ve cut the trace it isn’t doing that anymore, but it needs a signal from another input to tell the TV there’s something running for the MiSTer to display.

My plan now is to cut the trace leading to the switch pin marked 13 in the image, and the one leading away from the pin to its left. That will disconnect CEC, which I don’t need anyway. Then I can run wires from either side of where I’ve cut the +5v trace to those pins, and it will only connect if I’ve selected the MiSTer input. I’m not confident of my ability to solder to the tiny HDMI socket pins without creating shorts, so I’ll probably strip some coating from the trace and do it there.
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Re: Advice for HDMI users

Unread post by Yim »

OGJhmGk.jpg
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I modified my switchbox, and now I can connect my MiSTer to it without causing any troubles for the other inputs. It looks like a terrible bodge, but only because it is. I should have cut the wire shorter, at least. Anyways, now my MiSTer has all hdmi connections severed except for the grounds when I don’t have it selected on the box. When I do select it, CEC is still disconnected because of the traces I cut.

Is it normal that my MiSTer connects the hdmi ground and 5v pins when it’s turned off? Doesn’t seem right.
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Re: Advice for HDMI users

Unread post by bry111 »

Maybe a diode on pin 18 would help? Reminds me of https://www.retrorgb.com/cheap-fix-for- ... tters.html although it's not the same problem at all.
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Re: Advice for HDMI users

Unread post by jlancaster86 »

Has anybody tried using one of these breakout boards? Assuming the HDMI signal passes through correctly, it would be a lot easier to cut traces on one of these than trying to block/remove pins on an HDMI cable.
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Re: Advice for HDMI users

Unread post by jlancaster86 »

jlancaster86 wrote: Sun Jan 09, 2022 4:16 am Has anybody tried using one of these breakout boards? Assuming the HDMI signal passes through correctly, it would be a lot easier to cut traces on one of these than trying to block/remove pins on an HDMI cable.
I purchased a few of those HDMI breakout boards from AliExpress, and I can confirm they do work correctly. I'd recommend using one of those over hacking up a cable.
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Re: Advice for HDMI users

Unread post by Insert Disk Two »

Can this result in killing the HDMI port on TV? Because it just happened to me.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

jlancaster86 wrote: Sun Jan 09, 2022 4:16 am Has anybody tried using one of these breakout boards? Assuming the HDMI signal passes through correctly, it would be a lot easier to cut traces on one of these than trying to block/remove pins on an HDMI cable.
Whoa! That's exactly the kind of solution I've been looking for!

Any idea if/where I could get a nice little plastic or 3D-printed case to enclose the PCB?
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Re: Advice for HDMI users

Unread post by jlancaster86 »

keith.f.kelly wrote: Sun Feb 13, 2022 6:49 pm Any idea if/where I could get a nice little plastic or 3D-printed case to enclose the PCB?
No idea, sorry. But it couldn't be hard for somebody with the knowhow to whip something up.

Alternatively, some standoffs and two pieces of plastic would do the job.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

I bought a small bag of those HDMI M-to-F breakout test boards from AliExpress. They arrived yesterday. I'll be using them to finally conclusively determine which HDMI pins really need to be lifted to avoid all CEC, ARC, and eARC problems, and to maybe work with someone in the community who's handy enough with 3D modeling/printing to design and make little enclosures for these boards for anyone who wants to make a proper outboard inline multi-HDMI-pin-lifter for use with MiSTer.

The good news is these breakout boards have all pins connected by default, so to lift specific pins, all you have to do is scratch across the traces on the PCB for the pins you want to lift. So no soldering required, and would thus be an easy DIY project for anyone without much in the way of electronics skills. Would be pretty easy to manually produce batches of these by hand by anyone with a fine-point sharp metal scraper and a 3D printer.
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Re: Advice for HDMI users

Unread post by drgruney »

keith.f.kelly wrote: Wed Mar 02, 2022 7:18 pm The good news is these breakout boards have all pins connected by default, so to lift specific pins, all you have to do is scratch across the traces on the PCB for the pins you want to lift. So no soldering required, and would thus be an easy DIY project for anyone without much in the way of electronics skills. Would be pretty easy to manually produce batches of these by hand by anyone with a fine-point sharp metal scraper and a 3D printer.
For the sake of testing I would get two adapters with complete headers, and set up short jumpers. That way you can permutate without trashing any boards.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

drgruney wrote: Wed Mar 02, 2022 7:52 pm For the sake of testing I would get two adapters with complete headers, and set up short jumpers. That way you can permutate without trashing any boards.
I don't need to test very many permutations, and I'm handy enough with a soldering iron to reconnect any traces I've scratched out if it comes to that while I'm experimenting. But thanks for the suggestion :)
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Re: Advice for HDMI users

Unread post by jlancaster86 »

keith.f.kelly wrote: Wed Mar 02, 2022 7:18 pm I bought a small bag of those HDMI M-to-F breakout test boards from AliExpress. They arrived yesterday. I'll be using them to finally conclusively determine which HDMI pins really need to be lifted to avoid all CEC, ARC, and eARC problems, and to maybe work with someone in the community who's handy enough with 3D modeling/printing to design and make little enclosures for these boards for anyone who wants to make a proper outboard inline multi-HDMI-pin-lifter for use with MiSTer.

The good news is these breakout boards have all pins connected by default, so to lift specific pins, all you have to do is scratch across the traces on the PCB for the pins you want to lift. So no soldering required, and would thus be an easy DIY project for anyone without much in the way of electronics skills. Would be pretty easy to manually produce batches of these by hand by anyone with a fine-point sharp metal scraper and a 3D printer.
I cut the trace to pin 13 successfully, but I haven't tried cutting pin 14.

Simply cutting pin 18 (5 V) will probably break HDMI (it did for me). Adding a diode inline would likely do the trick, but i haven't tried it.
drgruney wrote: Wed Mar 02, 2022 7:52 pm For the sake of testing I would get two adapters with complete headers, and set up short jumpers. That way you can permutate without trashing any boards.
With or without the headers, those are just probe points, not jumpers (one per pin). That would be nice, though.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

Cutting the trace for pin 16 breaks video completely.

Cutting the traces for only pins 13 and 15 appears to work great.

Someone in Discord is suggesting I try to cut the trace for only pin 17. I'll try that next.
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Re: Advice for HDMI users

Unread post by jlancaster86 »

Pin 17 appears to be the ground for pins 13–16. If cutting pin 16 breaks video, then I expect cutting pin 17 would do the same.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

jlancaster86 wrote: Thu Mar 03, 2022 5:40 am Pin 17 appears to be the ground for pins 13–16. If cutting pin 16 breaks video, then I expect cutting pin 17 would do the same.
It does, as you suspected.
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

keith.f.kelly wrote: Thu Mar 03, 2022 4:20 am Cutting the traces for only pins 13 and 15 appears to work great.
Actually, cutting pin 15 solves some problems but creates others. Cutting it causes eARC negotiation between my VIZIO TV and my ThenAudio SHARC to intermittently fail. So I'm not sure I'd recommend that folks cut/lift pin 15 just yet.

This issue is being discussed in some detail -- specifically about that ESD chip -- right now in Discord. If the folks there manage to figure anything out, I'll report back here.
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Re: Advice for HDMI users

Unread post by Chris23235 »

I use a cheap HDMI Switch that is powered over a USB cable and have no problems with other equipment on the MiSTer. The other devices are even detected when turned on and the adapter switches to the corresponding input automatically. The switch works without the USB power but then takes a little bit longer to change the input. The switch has a button to cycle all 3 inputs and the all work fine at the same time.
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Re: Advice for HDMI users

Unread post by drgruney »

jlancaster86 wrote: Thu Mar 03, 2022 2:49 am With or without the headers, those are just probe points, not jumpers (one per pin). That would be nice, though.
That's why you get two adapters. So you can jump from one to the other. Pulling one line would functionally be like cutting a trace on a single adapter.
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Re: Advice for HDMI users

Unread post by Phaedrus »

keith.f.kelly wrote: Fri Mar 04, 2022 2:29 am
keith.f.kelly wrote: Thu Mar 03, 2022 4:20 am Cutting the traces for only pins 13 and 15 appears to work great.
Actually, cutting pin 15 solves some problems but creates others. Cutting it causes eARC negotiation between my VIZIO TV and my ThenAudio SHARC to intermittently fail. So I'm not sure I'd recommend that folks cut/lift pin 15 just yet.

This issue is being discussed in some detail -- specifically about that ESD chip -- right now in Discord. If the folks there manage to figure anything out, I'll report back here.
So what's the definitive answer?
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Re: Advice for HDMI users

Unread post by keith.f.kelly »

Phaedrus wrote: Mon Jul 25, 2022 9:24 pm So what's the definitive answer?
There isn't a "definitive" universal answer or solution. Nobody has gotten to the root cause of all this yet. All we have at present are workarounds that may help.

I just stumbled across this, which makes me wonder if it would help or if it's just snake oil:

https://www.crutchfield.com/S-23Su8PeBE ... M-JR3.html
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Re: Advice for HDMI users

Unread post by kingcar »

Finally the reason for causing problems on my Home Theater has been revealed. XD

I was always wondering why CEC wouldn't work when the Mister was hooked up to my AVR.
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