Advice for HDMI Users

[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.

[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.

[Yim]

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

s3m4Z8S.jpg (237.76 KiB) Viewed 12225 times

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.

[Yim]

OGJhmGk.jpg (180.75 KiB) Viewed 12155 times

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.

[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.

[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.

[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.

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.

[Insert Disk Two]

Can this result in killing the HDMI port on TV? Because it just happened to me.

[keith.f.kelly]

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?

[jlancaster86]

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.

[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.

[drgruney]

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.

[keith.f.kelly]

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

[jlancaster86]

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.

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.

[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.

[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.

[keith.f.kelly]

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.

[keith.f.kelly]

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.

[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.

[drgruney]

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.

[Phaedrus]

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?

[keith.f.kelly]

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

[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.

[desolationjones]

Bumping this ancient thread to register my data points:
MiSTer breaks my CEC/ARC if it is plugged into either my receiver (Onkyo TX-NR5100) or my TV (Samsung Q6FN).

Things that did not solve my issue:
Lifting HDMI pin 13
Lifting HDMI pins 13+15
Using a powered repeater, with or without pins 13+15 lifted

Things that maybe solved my issue:
Using a powered HDMI splitter (cheapest one on Amazon)

I only spent one evening with the splitter so far, but everything was well behaved. It also seems to have resolved an issue I had with the screen image oscillating/vibrating vertically when the MiSTer was plugged direct to TV (search me on Discord for video). I will report back here when I've spent a week with this setup.

[desolationjones]

Bumping this ancient thread to register my data points:
MiSTer breaks my CEC/ARC if it is plugged into either my receiver (Onkyo TX-NR5100) or my TV (Samsung Q6FN).

Things that did not solve my issue:
Lifting HDMI pin 13
Lifting HDMI pins 13+15
Using a powered repeater, with or without pins 13+15 lifted

Things that maybe solved my issue:
Using a powered HDMI splitter (cheapest one on Amazon)

I only spent one evening with the splitter so far, but everything was well behaved. It also seems to have resolved an issue I had with the screen image oscillating/vibrating vertically when the MiSTer was plugged direct to TV (search me on Discord for video). I will report back here when I've spent a week with this setup.

After four days with the splitter and some pretty intense MiSTer, PS5, Netflix, and PC sessions, I think I can call this solved.

The model of splitter I used was "avedio Links HDMI Splitter 1 in 2 Out, 4K HDMI Splitter for Dual Monitors Duplicate/Mirror Only, 1x2 HDMI Splitter 1 to 2 Amplifier for Full HD 1080P 3D with 5ft HDMI Cable (1 Source onto 2 Displays)" on Amazon.

[Allejo]

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 was having the same problem with the Mister interfering with the connection between the TV and the soundbar, luckily I found this thread and bought the breakout board jlancaster86 mentioned.

After I cut the trace to the pin 13 with a paper cutter (which is located on the back of the board), the soundbar and TV started working perfectly and I don't have any problems with the TV not having sound anymore. My TV is a Samsung 50QN90A, my soundbar is a LG SK6FF, and my Mister is the one from Retrocastle.

HDMI board 01.jpg (695.01 KiB) Viewed 6735 times

[LamerDeluxe]

It looks like the DE10 HDMI has just destroyed the displayport to HDMI adapter that was connecting the other HDMI port of my monitor to my PC.

The the HDMI 1 input of the second monitor of my PC is connected to the PC using a displayport to HDMI adapter, with my MiSTer being connected to HDMI port 2.

I turned on the MiSTer (using a socket switch) and the display signal of my PC disappeared at the same time. A bit later, I disconnected the PC HDMI cable from the HDMI to displayport adapter and the plug turned out to be very hot, almost burning my fingers. The adapter turned out to not be working anymore, it is less than two months old.

The other PC monitor was still working fine, displaying the PC signal and its adapter was hardly lukewarm at best.

Could the MiSTer be sending power up the HDMI cable, that ends up in the cable connected to the other monitor input somehow? I have a 4 amp power supply powering the MiSTer.

Or could the MiSTer somehow be draining power through the other HDMI port? I did have the mt32-pi connected powered by its MiSTer userport connection. I don't have the problem of the MiSTer getting (partly) powered from this monitor when the MiSTer is turned off.

At any rate, I should sever this power connection, because this is pretty insane. Thankfully the displayport of my (brand new) graphics card seems to be okay.

[Malor]

Using a CEC stripper on the Mister's output is a very good idea. It's known to cause havoc downstream; your converter may be poorly made and vulnerable to that kind of disruption.

It could be random coincidence, too, but the strippers are like $15, and may prevent later issues. They can apparently also cause some issues, too, as upthread it's mentioned that eARC negotiation can fail that way. But in that case, I'd just haul the audio via TOSLink instead.

It's possible that not carrying pin 13 could also cause issues with some flavors of VRR support. I added an LG 42" OLED and a stripper at the same time, and the Mister just gets a blank screen with NVidia-mode VRR support. It only works correctly with Freesync. (and only after a cold boot; warm boots frequently fail to display video.)

Since I'm really dependent on CEC working, I have not tried connecting the Mister without the stripper to prove the relationship.

[LamerDeluxe]

Using a CEC stripper on the Mister's output is a very good idea. It's known to cause havoc downstream; your converter may be poorly made and vulnerable to that kind of disruption.

It could be random coincidence, too, but the strippers are like $15, and may prevent later issues. They can apparently also cause some issues, too, as upthread it's mentioned that eARC negotiation can fail that way. But in that case, I'd just haul the audio via TOSLink instead.

It's possible that not carrying pin 13 could also cause issues with some flavors of VRR support. I added an LG 42" OLED and a stripper at the same time, and the Mister just gets a blank screen with NVidia-mode VRR support. It only works correctly with Freesync. (and only after a cold boot; warm boots frequently fail to display video.)

Since I'm really dependent on CEC working, I have not tried connecting the Mister without the stripper to prove the relationship.

I'm using older passive 3D displays, they don't seem to have any CEC support, so I think it should be okay. And they don't support any kind of variable frame rate.

It could be a coincidence. I've been having really odd behavior with my monitors blacking out momentarily, because my wife was moving a towel near the computer and similar weird things. All this seems to have started since I built my new PC with those adapters.

[KennyL]

I just found out about this issue after connecting a random 7" monitor I got from Amazon. The monitor powers on Mister via HDMI.

https://youtu.be/mmm54r6bsHE

I read through this thread and I'm not clear on if CEC less HDMI cables and devices would also not send power to Mister? Will it damage DE10 nano if I keep using it like this? I'll probably return this monitor either ways.