In this thread we build the projects that others have shared - Sony 129x clone card for PVMs

[bodgit]

I had the exact same thing with this version of the "full" bracket of thingiverse - the BNC connectors that I'm using are off aliexpress and don't really fit right, I think better quality ones might fit better
https://www.thingiverse.com/thing:4462796

That's the model I printed. In hindsight I should've spotted that my BNC connectors have one flattened edge so they're not entirely circular.

There is an alternative version here that is designed for the Aliexpress ones- I used this one as the basis for the double height bracket above, will report back when it's done printing
https://www.thingiverse.com/thing:4657838

I'll order a print of this one and see if it fits these BNC connectors better. I really should buy a 3D printer at some point...

 

[hatmoose]

I really should buy a 3D printer at some point...

I only know you from tinkering with electronics, but I think you would absolutely love a 3D printer - I bought a Creality Ender 3 pro on special for $200 shipped (to NZ!) a couple of years ago and it's probably the best $200 ever spent.

Did a test print of the double-wide bracket, pretty happy with that good, just a few minor tweaks and 6 more hours printing...



Then I'll need to figure out how to wire the BNC connectors on the "full size" card to the SCART pins on the "VGA/SCART" card.

 

[bodgit]

I only know you from tinkering with electronics, but I think you would absolutely love a 3D printer - I bought a Creality Ender 3 pro on special for $200 shipped (to NZ!) a couple of years ago and it's probably the best $200 ever spent.

What always stops me is that I feel like I'll use it for whatever the immediate need is and then it'll sit there gathering dust, (not that that has ever stopped me with anything else!). It would literally be used for printing brackets, mounts, etc. I don't really have any desire to print out models of dragons, etc.

Did a test print of the double-wide bracket, pretty happy with that good, just a few minor tweaks and 6 more hours printing...



Then I'll need to figure out how to wire the BNC connectors on the "full size" card to the SCART pins on the "VGA/SCART" card.

I was wondering how you were going to do this. The main problem I could see is that the original 8x BNC board has the four switches to enable/disable the 75Ω termination on the passthrough so you either do away with those and live with always having to use some external terminators, but then they will likely interfere with the SCART lines so you'd have to take them off again, etc.

With my engineering hat on, what I was thinking of is to replace the current 4P2T VGA/SCART push switch with some sort of 4P3T slide switch so you can have VGA/SCART/BNC and keep each input isolated. Then have a narrow second PCB with just the BNC connectors and the 4x 75Ω termination resistors/switches and stack it on the main PCB with some standoffs and headers to pass the RGBS signals. I think the trickiest bit is finding a suitable alternative switch, assuming I've got the number of poles/throws right but I'm sure there'll be something on Mouser.

I'd have a go at merging the two PCB schematics together if you fancy it?

 

[hatmoose]

What always stops me is that I feel like I'll use it for whatever the immediate need is and then it'll sit there gathering dust, (not that that has ever stopped me with anything else!). It would literally be used for printing brackets, mounts, etc. I don't really have any desire to print out models of dragons, etc.

With my engineering hat on, what I was thinking of is to replace the current 4P2T VGA/SCART push switch with some sort of 4P3T slide switch so you can have VGA/SCART/BNC and keep each input isolated. Then have a narrow second PCB with just the BNC connectors and the 4x 75Ω termination resistors/switches and stack it on the main PCB with some standoffs and headers to pass the RGBS signals. I think the trickiest bit is finding a suitable alternative switch, assuming I've got the number of poles/throws right but I'm sure there'll be something on Mouser.

I'd have a go at merging the two PCB schematics together if you fancy it?

You're absolutely right, my current plan was to hardware the BNC output to open, terminate with external terminators and take them on/off as required. Being able to switch all the inputs and associated termination from the outside would be a much more elegant solution.

And also strongly in favour of the BNC PCB being a kind of sub-board that attaches nicely via headers. I think if we could do those things this would be getting close to "finished". Then it would be possible to have pretty much every single analogue input in the one monitor - how cool would that be?

Yes, if you were keen to have a go merging the schematics I've got lots of parts left.

 

[hatmoose]

Haha, it aint pretty, but it works as expected.

It was even less pretty when I discovered that the cage that holds the cards is about 2mm shorter on the right hand side than on the left, 2mm doesn't sound like much, but it meant that for all the ports to line up the card was not fully inserted into the edge connector. Clearly the only solution was to cut the back off the PCB.

But once its fully assembled it actually looks pretty darn good

 

[hatmoose]

STL for the double width card is attached - this one should print without errors - some rework required to drill out the mounting screw holes

 

[hatmoose]

Have been using this without issue for the last few weeks - great to have all the inputs, all in one place, all the time.

I probably would not make another one - there is a massive amount of manual rework, but I did have a lot of fun.

Unless a 9L3 somehow comes into my life, or even better a BVM-D9H, then I'm going to call this project "done"

 

[Family]

I also urgently need some cards for my BVM A devices. That would be awesome..finally rgb.

 

[hatmoose]

I also urgently need some cards for my BVM A devices. That would be awesome..finally rgb.

I don't have an a-series BVM, or any way to get one (tiny island, middle of nowhere). But I did seriously look at making these a while back.

I don't think PCBway or any of the others would be interested doing automated manufacturing but a board like this is no challenge for home fabrication.


The limiting factor is that several of the parts are parts that are now impossible to get with the global component shortage. Suppliers aren't even accepting backorders any more, just... gone https://www.digikey.com/en/products/detail/intel/10M08SAU169I7G/5429537 and with the current ChinaUS tensions its possible that these parts will never be available to hobbyists again.

 

[bodgit]

I started looking at merging the boards. Logically it's easy to do with a 4P3T switch, (I did get the poles/throws right!). However the hard bit is finding room on the back of the card for what is physically a larger switch than the current 4PDT push switch; there's not a lot of spare space.

I did wonder if it was possible to use some sort of analogue switch IC instead and then you could just have a tiny µC reading a momentary button and cycling through each of the three inputs, i.e. VGA -> SCART -> BNC -> VGA -> ...

 

[hatmoose]

I started looking at merging the boards. Logically it's easy to do with a 4P3T switch, (I did get the poles/throws right!). However the hard bit is finding room on the back of the card for what is physically a larger switch than the current 4PDT push switch; there's not a lot of spare space.

I did wonder if it was possible to use some sort of analogue switch IC instead and then you could just have a tiny µC reading a momentary button and cycling through each of the three inputs, i.e. VGA -> SCART -> BNC -> VGA -> ...

Interested to see what you come up with! I'm just starting to teach myself Kicad now. 6.0 is much easier to use, but it's still bloody hard

 

[bodgit]

I couldn't find an obvious IC that implemented a 4P3T switch, but I did find an IC (TS5A3359) that implements a single SP3T switch so the obvious thing to do is just use 4 of those chips, one each for the R, G, B & S lines and tie their logic pins together so they switch in parallel.

Something like an Attiny[248]5 µC has just enough spare pins to read a button and drive the two logic inputs for the switch IC(s) with some dedicated firmware, I could use the Atmega that's already on the board with some tweaks to the existing firmware but I'm hesitant of messing up the timing between the board and the host PVM so I might keep it separate.

I found a leftover reel of the switch ICs on eBay so I'm going to breadboard a prototype hanging off the back of my BNC 129x clone, the only problem is these are a VSSOP8 package so they're a bit fiddly to solder.

 

[bodgit]

I finally got everything together to prototype my idea:

On the left are three RGBS inputs; my super gun via its VGA output with a MiSTercade hooked up and two SCART feeds from my SNES and Jaguar. On the right is a VGA connector that goes off to the BNC BKM card in my PVM. In the middle are four of the switch chips, one each for R, G, B & S. The two logic inputs on the switch chips are all daisy chained together and driven by the Arduino which also reads the small momentary button. The firmware on the Arduino simply reads the button and counts 1, 2, 3, 1, 2, 3, etc. with every button press and then translates that value to the two logic lines so the four switch chips cycle through their inputs in parallel.

75Ω termination is done on each input (the theory being the BNC input termination will be selectable) and I disabled the termination on the BKM card so between the switch outputs and the THS7374 chip on the BKM card is a sole 0.1µF capacitor in series on each line. All of the GNDA connections on the inputs and output are tied together. I used the ICSP header on the BKM card to get an easy +5V/GNDD supply for the logic.

It seems to work fine. I can detect ever so slight interference on the PVM but I think that's just a combination of the breadboard and jumper wires, I suspect it won't be present on a routed PCB. The switch chips being a VSSOP package aren't impossible to solder by hand but definitely non-trivial.

Next step is to integrate what is in the middle of the breadboard into the existing PCB design and re-route where necessary. I will try and reuse the existing Atmega and adapt the firmware as the changes are pretty simple. I can make use of the integrated EPROM in the Atmega to remember the last input so it doesn't always switch back to the first input on boot.

 

[bodgit]

I emailed Martin, the original designer of these clone boards, about something I'd noticed with the schematics and mentioned my plan to make an all-in-one card and he suggested maybe adding in an autodetect feature so the card will scan each input in turn for a valid signal.

I found an LM1881 sync stripper IC in my spares and added that to my test circuit fed by the SYNC signal of the active input. That produces a clean VSYNC signal and using the Arduino I can then count the number of pulses per second and if it's somewhere between 50 and 60 then chances are it's a valid signal and the card stays on that input. If it's outside that range then the card switches to the next input, and so on. I'll probably still keep the button as a manual override in case there's more than one valid signal and the card locked on the wrong one, etc.

 

[bodgit]

I noticed one annoying problem when I tried my PS2 with its VGA cable. For those not aware, the PS2 VGA output uses Sync-on-Green. My PVM happily shows a stable image, but doesn't compensate for the sync signal being mixed in with the regular green signal and so the whole picture has a strong green tint.

I couldn't leave that unfixed and actually it turns out Martin had added a similar circuit on his more advanced BKM-68X clone board so I adapted and merged that into my design. It requires a slightly different sync stripper IC and some additional logic.

The PCB is 99% done, just some minor silkscreen tweaking to do. You can see there are quite a few additional components now:

Here's the smaller BNC input PCB that stacks on top:

I've gone for some JST NH connectors and a short wiring harness to connect the two PCBs together and 4x M3 brass or nylon standoffs keep everything bolted together.

@hatmoose could you check the distance between the two PCBs on your stacked set? I think 24 mm standoffs might be about the right gap.

 

[hatmoose]

This is the most beautiful thing I've ever seen - thank you for all of your hard work, I'm proud to be a small part of it, this truly is a work of art.

Will measure the gap between boards as soon as I'm home, next 24 hours, and post here.

Minor sidenote - when you have a 3D printer you never need to order another standoff, can print to whatever specs you like whenever you want - is very lovely.

QQ on the Playstation thing, if you're using a VGA cable does that imply you're using this on a 480p capable PVM, 14L5 style?

 

[bodgit]

This is the most beautiful thing I've ever seen - thank you for all of your hard work, I'm proud to be a small part of it, this truly is a work of art.

Thanks, although I’ve no idea if it works yet. I’ll have to get some PCBs produced and then the fun of acquiring the components. Hopefully I’ve not made a mistake…

Minor sidenote - when you have a 3D printer you never need to order another standoff, can print to whatever specs you like whenever you want - is very lovely.

I see what you’re trying to do there! I’m going to need to do something for the bracket as I suspect all the various ports and buttons are not quite in the same place now. Might be the excuse I need…

QQ on the Playstation thing, if you're using a VGA cable does that imply you're using this on a 480p capable PVM, 14L5 style?

I just powered up with no disc and I got the BIOS/boot screen, albeit very green, on my 9L3. I couldn’t remember offhand which games support the VGA cable. I just thought to try a SoG source to see how it worked and the PS2 is the only device I think I’ve got. Chances are I’m more likely to use component anyway but I felt I should make it as usable as possible.

I don’t know if other PVM/BVM models handle SoG better, I feel some of the fault is with the PVM as it clearly detects the sync signal on the green channel which is normally half the battle; most monitors usually only expect separate H/V sync.

 

[hatmoose]

Here we go.

I modelled the gap between the boards as the same as the gap between the mounting holes which was 23.5mm

23.5mm feels like a weird number, I'm guessing its some commonly used imperial fraction?

3D printing is an inexact science so the way it came out in real life was 23.35mm

Sooo either 23mm or 24mm should do the trick.

Let me know when you are feeling good about the component placement - I need to to a PCB order anyway so I'll fab up some boards and re-draw the bracket.

Oh, also - JST NH is a super cool connector and I love it - have been looking for some 13 pin right angle headers for a NeoGeo Marquee project that I have not written up yet - 5 pin seem to be common but all the others are hard to get. Any leads on the 13 right angle pin jobs?

 

[bodgit]

Here we go.

I modelled the gap between the boards as the same as the gap between the mounting holes which was 23.5mm

23.5mm feels like a weird number, I'm guessing its some commonly used imperial fraction?

3D printing is an inexact science so the way it came out in real life was 23.35mm

Sooo either 23mm or 24mm should do the trick.

Thanks. I stacked my two BKM-129X clones together by the brackets and measured roughly 24mm between them but the boards wouldn't stay parallel. For the sake of 4 standoffs I'll try and get both 23 and 24mm and see which fits better. It might be that one size isn't available anyway...

Let me know when you are feeling good about the component placement - I need to to a PCB order anyway so I'll fab up some boards and re-draw the bracket.

I think I've tweaked them enough, I just wanted to make sure I credited Martin somewhere on the PCB for the original design(s). I've set up a CI/CD workflow on Github so the Gerbers and BoM are built automatically. If you use a fab other than JLCPCB then let me know, I can possibly build an additional set of Gerbers tweaked for whoever.

The project is at https://github.com/bodgit/bkmm-129x-ultimate, just navigate to the releases and everything is there for both boards. I'll add the Arduino firmware and an STL file for the bracket later.

Just be aware I've not tested this yet so it might destroy worlds and/or PVMs.

I've finally succumbed to a 3D printer too, although it'll take a few weeks to arrive. Something about beg for forgiveness rather than ask for permission springs to mind...

Oh, also - JST NH is a super cool connector and I love it - have been looking for some 13 pin right angle headers for a NeoGeo Marquee project that I have not written up yet - 5 pin seem to be common but all the others are hard to get. Any leads on the 13 right angle pin jobs?

I think they're quite hard to get in general. I might live to regret picking that connector although I can probably use a genuine or clone XH in a pinch as it's the same pitch. I found RS have the right angle 5 pin PCB connector, but nothing for the cables so I'll have to hunt for those. They had the straight 13 pin PCB connector, but I couldn't see a right angle version in or out of stock. Ages ago I made some KiCad 3D models for the NH connectors and there's essentially three variants; straight, right angled, and an odd upside down version. I remember that not all variants are available in every pin count, it might be that the right angled version isn't available for 13 pins.

 

[hatmoose]

Thanks. I stacked my two BKM-129X clones together by the brackets and measured roughly 24mm between them but the boards wouldn't stay parallel. For the sake of 4 standoffs I'll try and get both 23 and 24mm and see which fits better. It might be that one size isn't available anyway...

I think I've tweaked them enough, I just wanted to make sure I credited Martin somewhere on the PCB for the original design(s). I've set up a CI/CD workflow on Github so the Gerbers and BoM are built automatically. If you use a fab other than JLCPCB then let me know, I can possibly build an additional set of Gerbers tweaked for whoever.

The project is at https://github.com/bodgit/bkmm-129x-ultimate, just navigate to the releases and everything is there for both boards. I'll add the Arduino firmware and an STL file for the bracket later.

Just be aware I've not tested this yet so it might destroy worlds and/or PVMs.

I've finally succumbed to a 3D printer too, although it'll take a few weeks to arrive. Something about beg for forgiveness rather than ask for permission springs to mind...

I think they're quite hard to get in general. I might live to regret picking that connector although I can probably use a genuine or clone XH in a pinch as it's the same pitch. I found RS have the right angle 5 pin PCB connector, but nothing for the cables so I'll have to hunt for those. They had the straight 13 pin PCB connector, but I couldn't see a right angle version in or out of stock. Ages ago I made some KiCad 3D models for the NH connectors and there's essentially three variants; straight, right angled, and an odd upside down version. I remember that not all variants are available in every pin count, it might be that the right angled version isn't available for 13 pins.

This is such a treat - always a pleasure to see the work of a master, so many sweet little touches in there. I particularly like that you moved the edges of the ground plane in from the edge of the board. If the solder mask rubbed through against the edge of the guide there won't be conductivity. I'm sure there are a million more that I haven't found yet