Blast VS Kit Frankenstein - Advice wanted. Pics pls? Pinout maybe?

[GeeDee]

Tl;dr: how tf does wiring 15khz from jamma work with the buffer board? I only have the buffer board and not the full kit, so im planning to make my own harnesses. Pics appreciated.

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So I have two cabs atm that I would very much like to have the option to link- a blast and astro city. Now hang on, before you go all "You need a 2nd Blast I/O" on me, I know that. Hear me out.

For starters I 300% plan to get mikes VS board whenever that is finished up, but until then, I just wanna explore my options. I don't have the Entire Blast vs kit, but my blast DID come with the video buffer board. This goes into my second point: "Why not just make a VS cable out of some jamma fingerboards??" If you read up on this like I've tried to do, you'll find one handful of people going "I made this and it works great for me!" then another handful of people saying "OK but your video is either going to be dim or have poor sync since you're splitting the signal in half. Also you should do something to put the 5v on the 2nd cab under load." The buffer board that I have should solve that split signal issue, though I have some questions about it since I feel like I'm getting some conflicting info from the manual and AO Wiki. Obviously this thing is just meant for connecting one blast to another, but the manual does say that it supports both VGA and Jamma; i.e. a 15khz signal. My hope plan is to just build some cables myself to compensate for the missing harness out of (maybe?) an original JST RA on the blasts I/Os C7, then a DB15 -> astro RGB in from the video buffer board. I'll be putting all the pics behind spoilers so the thread is a little less cluttered, but for reference, here's the buffer board so you have an idea of what I'm looking at/thinking about:

Spoiler: buffer board

Here's the first part of my conflicting info:

Spoiler: AO Diagram

This isnt official- it's just a cute little diagram someone made and put up on the AO wiki that describes how to connect to the buffer board form a Jamma PCB. I can't really tell what the "001" loom is, since the only thing I know for sure that connects to the Blast I/O board is the short DC 12V harness that powers the buffer board. Otherwise, it COULD be the RGB-in from jamma, but it's hard to tell becuase...

Spoiler: VS Manual Diagram

Here's a sc from the VS kit manual. The 6pin header on the buffer board shows rgb signals going (what I assume is) into the buffer board from the blast I/O at c7, then OUT via DB15, then connected to the other blasts I/O by another 6 pin harness...making the cn7 port both an RGB in, AND out? The rest of the inputs from cn7 travel through that JST RA connecter to a panel the vs kit came with that I dont have- no biggie, the plan is just to make my own harness for controls anyways since there's no worries about sync or anything like there is with the video. In fact, if I just look at the pinouts for cn7 in the blast manual I should be able to figure out if cn7 is an RGB-in or out, and then...

(Edit: Just now seeing I missed the "NO USE" on the rightmost side terminal board for 2P. I'm guessing this confirms that the RGB lines on cn7 are definitely an OUT? Since the DB15 on the buffer board goes up into the d-sub input on the monitor from there lmk if I've got that right. Anyways, about the remaining pins...)

Spoiler: Blast manual "pinouts"

...oh. The Blast manual doesn't HAVE cn7s pinouts...and neither does the VS kits manual...awesome

I have a feeling something simple is just soaring over my head right now, so if you wanna point me in the right direction, it would definitely be appreciated lol. Also, if you happen to have pics of a VS kit you have using rgb from jamma, that would definitely help as well. Would also like suggestions for good methods of putting the astros 5v under load without a game board.

The "big jamma fingerboard harness" Could work if im only using it for easily routing the 2P controls, so if the JST RA pinouts don't poof into existence so I can go about it that way, I'm thinking about maybe like...soldering a jamma edge to one end of a fingeboard for the 2P side, plugging in a spare cheap dotorikun there, then cutting the traces or hijacking the wires for controls/video/sound/etc so the only thing the dotori is there for is to have something occupying the 5v line. I'm no electrician, so that's just my spitball "using what ive got" idea

 

[ItsBobDudes]

Could THIS do what you are looking to do ?

 

[GeeDee]

Could THIS do what you are looking to do ?

Yes in that I want to link two cabs with just jamma/15khz.

No in that this looks like another harness that doesn't provide any kind of amplification/buffer for the rgb (or a load for the 2P cabs 5v line).

See This Thread for examples of homebrew cables/harnesses like this that people have made before for this purpose, but still run the risks of not having the proper hardware that a genuine vs kit would provide. I could make one of these same kinds of harnesses if I wanted to, but I want to know good ways to avoid the issues caused by splitting the video signal, as well as keeping the 2P power supply running healthy. These cabs would potentially be on for many hours a day on location, so I don't wanna run the homebrew "Meh, it's fine for a little home session" risk.

 

[Anselmo]

Does the Axun Works solution not accomplish this either? The jamma extractor has the versus capability. I have an official full Blast versus harness I can take pictures of for you if that would help

 

[Anselmo]

Check out this nice breakdown that was given to me when I purchased this kit. Hope it helps!

 

[GeeDee]

Does the Axun Works solution not accomplish this either? The jamma extractor has the versus capability. I have an official full Blast versus harness I can take pictures of for you if that would help

Not gonna lie I had completely forgotten this was an option; I actually have another main jamma extractor unit, just not the 2P part. Though ive largely kind of removed that from my mind since I bought an extractor before they made those fixes removing resistors to fix the color/wash issues that the first run (the one i bought in on) was having. Might order one of the 2P bits and just deal in the mean time while I sort this out I definitely want more vs kits prepped for the future, so I'd still like to figure out how I can incorporate this video board in another homemade harness.

Check out this nice breakdown that was given to me when I purchased this kit. Hope it helps!

Thanks for this! Though the "A" section: "this is a vga cable it's self explanatory etc etc is kind of part of my confusion lol. By "self explanatory" does that imply that should be connected to the monitor, or is it an /in/ going from something like a naomi or jvs etc? And that "extra kick harness" is actually used for rgbs so says the manual; not buttons, so that leads me to believe that would be the video buffer boards rgb-in, since it's "not used" on the 2P side, again, so says the manual

 

[Anselmo]

yea, that's definetly looking like RGB Ground Synch Signals. Let me take a look at this. when I get home later. I ran it one time and haven't used it since, because well, a pandemic. lol.

 

[GeeDee]

Thanks! Definitely appreciate the help from someone who actually has a kit. This wouldn't be so complicated if the blast or vs manual detailed the pinouts on cn7, but, oh well

If that small header really is buffered rgb /out/, or if it's just some shared rgb with cn5, I'll know where I need to tap into to make a harness leading from the buffered signal and send it out to the astro.

 

[nem]

Yes in that I want to link two cabs with just jamma/15khz.

No in that this looks like another harness that doesn't provide any kind of amplification/buffer for the rgb (or a load for the 2P cabs 5v line).

I'm just going to chime on this, it's fine as long as you have two similar monitors. If there's an impedance mismatch, then you can run into issues. I ran a VS setup with two Astros with MS8s for a really long time. With regards to the PSU running without a load, I just unplugged it on the 'slave' cab. It's like a two minute job with an Astro that has the PSU with the front facing buttons. Flip the PSU enclosure, unplug the three pin connector to the PSU and carry on.

It's certainly better if you have buffered output, but you can get away with just a split signal.

I've never owned a Blast VS kit. That has eluded me so far.

I can't really tell what the "001" loom is

The 600-7143-001 is the extended loom with JVS power connectors and stereo input. I don't see any reason why you would need that specifically.

 

[ebzero89]

I built one of those split loom/jamma fingerboard style splitters and it works fine for me atm. I haven't ever heard of needing to put a load on the 5v rail of the 2P cab. Why would that be? Is that something astro specific or does it apply to any cab? Is it a fire hazard or would it damage the PSU somehow?

 

[nem]

It applies to any switching mode power supply. No load can damage it. Look it up.

 

[GeeDee]

The 600-7143-001 is the extended loom with JVS power connectors and stereo input. I don't see any reason why you would need that specifically.

Thanks! I actually do have this- grey hair moment on my part. I knew the name of that loom rang a bell but I seriously thought it was referring specifically to JUST the DC 12v cable used for the buffer board. Like you said though, not that it matters much, I had just planned on making a harness and splicing in some 12v from somewhere else.

It's fine as long as you have two similar monitors. If there's an impedance mismatch, then you can run into issues. I ran a VS setup with two Astros with MS8s for a really long time.

It's certainly better if you have buffered output, but you can get away with just a split signal.

First, thanks for chiming in with all the info! Just a few questions:

So I have an ms-2930 in the blast, and an ms9-29s in the astro. Am I running any risks here? If there's a good place to read up more on checking/understanding the impedance then I'd love to look into it, but totally transparent, I haven't had anything project/task/etc wise that would need me to consider that just yet. New-er territory for me.

With regards to the PSU running without a load, I just unplugged it on the 'slave' cab. It's like a two minute job with an Astro that has the PSU with the front facing buttons. Flip the PSU enclosure, unplug the three pin connector to the PSU and carry on.

Unless I'm having another small-brain moment, I don't think I can take my psu out of the picture completely given the model that I have (but I'd love to be wrong if it's that simple)? I have a 400-5198-01X, the slimmer model with the vertically facing buttons. Just spitballing here, but I /could/ (I think) just disconnect the top connector since that only supplies 5v, 12v and some grounds, and just keep the rightmost connector plugged in since that's running up to the monitor, though I mean afaik this still means I'll be running the cabs psu without a load on any of the other lines. I've never owned an ms8 so I don't know the wiring differences and etc. Here's the PSU I have just for the reference as to what I'm looking at:

Spoiler: 400-5198-01X

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Also, I took a look back at that AO thread I linked earlier, and just realized you also chimed in over there some odd years back. I didn't see the names were the same since I only know you here with the elmo pfp lmao. I'm hoping to run some 3S in these as well at some point, can I ask you to elaborate a little when you mentioned having differences in the speaker lines?

 

[nem]

So I have an ms-2930 in the blast, and an ms9-29s in the astro. Am I running any risks here?

I don't think there's any risks. I think it's worth trying. If one side seems visibly out of focus or dim, you'll want buffered output.

Unless I'm having another small-brain moment, I don't think I can take my psu out of the picture completely given the model that I have (but I'd love to be wrong if it's that simple)?

You can, but it's not as elegant. You have to remove the whole PSU. Instead of a two minute job, it's like three minutes at most. There's two screws on top (the two that are aligned vertically) and one on the underside (on the top-right, the one that attaches to the enclosure). Then you just pull out the PSU (while it's out you can recap it!).

 

[Anselmo]

I can tell you I run a ms9 and a ms2930 linked up for hours at a time and there's no issues with the impedance or dimness or focus.

 

[Anselmo]

So I ran into an issue with my blast versus harness. At first I was able to get the naomi picture on both screens, but then on the second try, I was getting what looked like an out if sync picture on one. Now both blast show an out of sync picture when I connect the versus kit, specifically when I connect the RGB connection to the video buffer board. If I disconnect the RGB connector from the buffer board, the picture is restored immediately. Plug that connector back in, picture becomes garbled, like out of sync. I've tried this on both 31khz and 15khz, and both blasts. :/

 

[ebzero89]

It applies to any switching mode power supply. No load can damage it. Look it up.

So how does this work with games that don't need a -5v rail, or 3.3v? Does playing those games on a Blast City cabinet risk damaging the blast PSU? Do all boards regardless of if they use it or not, just put resistors or something on those rails to prevent damaging arbitrary cabinet power supplies?

 

[GeeDee]

You can, but it's not as elegant. You have to remove the whole PSU. Instead of a two minute job, it's like three minutes at most. There's two screws on top (the two that are aligned vertically) and one on the underside (on the top-right, the one that attaches to the enclosure). Then you just pull out the PSU (while it's out you can recap it!).

Thanks! Will look more into this if the impedance isn't going to be an issue between these two. I was hoping to do this buffer board/dotori solution so this could pretty quickly be a process of switching from a VS/"slave" cab and then going right back to being a standalone 2L12B when I need it to be, so I'll have to see what all goes into the process.

Also, not to be a bother, but, reposting:

Also, I took a look back at that AO thread I linked earlier, and just realized you also chimed in over there some odd years back. I didn't see the names were the same since I only know you here with the elmo pfp lmao. I'm hoping to run some 3S in these as well at some point, can I ask you to elaborate a little when you mentioned having differences in the speaker lines?

 

[Aurich]

Not an expert in any of this, just my two cents from experience:

I run two linked Astro City setups with just straight up homebrew fingerboard looms, and we put a big ol ceramic resistor on the slave side to load up the PSU.

Been using that way for years, no problems, no dim pictures, no sync issues.

 

[nem]

Also, I took a look back at that AO thread I linked earlier, and just realized you also chimed in over there some odd years back. I didn't see the names were the same since I only know you here with the elmo pfp lmao. I'm hoping to run some 3S in these as well at some point, can I ask you to elaborate a little when you mentioned having differences in the speaker lines?

You will want to check what kind of load you're putting on the amp. Astros have volume pots as well. So there's a volume pot wired in parallel (I think) with two speakers that are wired in series. I don't know how it's wired up in a Blast, probably the same? Then with a versus cable you're wiring the two cabs in parallel. It's a mess. You can measure the DC resistance between speaker + and -, but it doesn't necessarily tell the whole truth. Honestly, a better way to check is to put your finger on the audio amp heatsink. If it's burning hot, it's wired wrong. Utimately, I fixed this by using the line out on the CPS3 and a separate amp.

 

[GeeDee]

Utimately, I fixed this by using the line out on the CPS3 and a separate amp.

Interesting- I can definitely do this no problem. I have a few spare Amps around that I can wire up for just this if it'll dodge all the speaker issues; just add a y splitter to the cps3 and have one end go directly to the blast stereo and an extra 3.5mm lead go into a separate amp in the astro. Make a little harness or something to go from the astro speakers to the spare amp, etc.

Wiling and able to do all this, but man, Mike's board can't come fast enough I guess lol. Don't really have a lot of faith in the jamma extractor after that whole ordeal and this whole process is a bit of a chore oh well, something fun to take up a weekend sometime soon. Thanks again to everyone that chimed in.