retro_doog

No interest on these? I forgot to add these shells are all from New Old Stock carts that had the board pulled out. Actually a handful still have the cart board inside(usually the undesirable titles like Personal Real Estate)... If there are any takers, feel free to make an offer on the lot of them!

Just an update, these have all been sold and shipped. Thanks to all who showed interest!

Bought these several years ago when I was planning my own Multi-Cart. Now.... well there are enough capable multicarts out there. I suppose with a little dremeling one could use these shells for the custom carts on the market? I've got 30 of these. Prefer to sell all at once. The less you buy the higher cost per shell. Make a pre-shipping offer and let me know your zip code. Shipping's not free, ya know! I'm not Amazon

Looks like I have roughly all of these sold. Just need to order parts and assemble/kit them up. I'm not likely to build any more single units myself, but I may be willing to sell batches of minimum Qty 10 bare PCBs to others who want to assemble and sell these. The cost would be the actual PCB Cost plus a small per board royalty. A sort of "pseudo-license" if anyone is interested...

Looks like there's enough interest to order parts to kit and/or assemble these. After considering the BOM cost and time spent assembling/packing/shipping, I'm going to be at $20 + Shipping for a solder it yourself kit or $40 for a fully assembled board. If there's more demand than for just the 4+1 I have currently, I suppose I could order more PCB blanks. I'm also OK will selling PCB blanks in multiples of ten if others want to assemble and sell these.

I made a PCB to allow me to probe a TI-99 Cartridge in action. It's basically a pass-though with some logic analyzer probe pods with the Address, Data, and Control lines organized nicely. I have one assembled unit and four bare PCBs. Not sure whether to sell assembled, as solder yourself "kits", or just the bare PCB. If there's any interest in these PM me and we can work out the details. I'm limiting this to US buyers with PayPal accounts. That way there is a record of transaction and a way for me to confirm postage and tracking as a way to protect both buyer and seller. Thanks for looking!

The video link doesn't seem to work for me. I'm guessing this is the ST:TNG Scotty and LaForge scene?

I was be facetious in my post Actually, you'll want to read my first post for my opinion of anything large and brick-like for the first stage supply. The entire point of my project is to replace the large, heavy floor brick with something more like one of these: https://www.digikey.com/products/en/power-supplies-external-internal-off-board/ac-dc-desktop-wall-adapters/130?FV=57|318132%2C57|318134%2C57|318137%2C57|318143%2C57|318171%2C57|318172%2C57|318173%2C57|318175%2C57|318178%2C57|318180%2C57|318182%2C57|318183%2C57|318185%2C57|318187%2C57|318191%2C57|318193%2C57|447538%2C57|447539%2C1371|379518%2C1989|0%2Cmu10W|2187|0%2Cmu30W|2187|1%2C-8|130%2C48|103542%2C48|116509%2C48|234830%2C48|235004%2C48|270755%2C48|305478%2C48|74515%2C48|87718%2C48|89177&quantity=0&ColumnSort=1000011&page=1&stock=1&k=ac+adapter&pageSize=25&pkeyword=ac+adapter You can get up to 24W in quite a small wall mount package! The internal supply I'm designing accommodates these compact external supplies in two ways: 1. The internal supplies are now all DC/DC not Low voltage AC to DC like the original. 2. The internal supplies are substantially more efficient, thereby further reducing the wattage requirement, and thus the size and cost, of the external supply. Also, in the world of power supplies, the simplest design(Transformer+cap, for instance) are usually the least efficient. For example, I've read that the ferroresonant XFMR is actually very inefficient at low loads. Take your Bench Supply, for example. Does it not get quite warm/hot? If so, that is all wasted energy not being presented to the output. Also, the "buzzing" noise you hear from transformers is also wasted energy. Electricity being converted into mechanical energy + heat. Modern semiconductor controllers can adapt to the load ensuring high efficiency across a range of loads. Not terribly important for our TI consoles, but super important in modern machines. Did you know that the core typically 1.0V power supply for, say, an intel processor running at a few GHz will draw a maximum of 50 Amps or more? And yet, it has many power modes that draw dramatically different amounts of power, so the current draw is actually violently "trashing". Imagine the power supply that has to handle that! And yet, it can be implemented in a couple square inches of PCB space and run quite efficiently across the wide range of load currents. Despite the older, higher voltage, technology in our TI Consoles, the power requirement is quite low. A bit less than 10W, I'd say. The semiconductor supplies I'm designing in will be small, cool, and efficient. When you get a look at the finished product, you may have a hard time believing it is not only powerful enough to run the machine, but will actually have about 150-200% of the potential capacity of the original, especially if you're used to looking at old hardware. ? It's a bit early for testing, but thanks for the offer I'll probably be recruiting a handful of beta testers to help out. They'll have to do a little work for me though, like measuring under different loads etc. I'll probably want people with specific external equipment to help me test like the TiPi, RF-Modulator, and so forth. I just have a console and a Speech Synth myself...

Ah, of course! I'm designing in a 300-400mA capable 12V boost supply, so that should leave plenty of additional capacity for an external regulator. I just don't have one on hand to actually measure the exact amount of additional current needed, but I suspect it is only 50-100mA...

I... Don't know quite what to do with that. Looks like a Bench test supply, which are designed with a lot of extra features to ensure the supply isn't damaged when testing faults on the unit under test(ie destructive testing). I'm sure a smaller, solid state version with the same features exists. Of course that is an AC power supply. I'm designing a modern DC to DC supply board that fits inside console. There will still be an external off the shelf AC/DC supply used, but the choices now are much smaller for equivalent power as they use semiconductor switching instead of large wire-wound transformers.

I'll be using modern switching controllers complete with internal protection circuits. These things work with very small inductors as they operate at very high frequencies. The -5V inverting switcher is something like 2Mhz. I believe the boost regulator is 500KHz. Trust me, electronics in the power supply is a better solution than wirewound/heavy core transformers. We're only talking about a few hundred milliamps for the boost regulator. Most of these modern switchers are stable with ceramic filter caps as well due to the high switching frequency. You'll be surprised at how compact these modern supplies will be. The main variable for me will be how much Bulk capacitance to put on the board. I'll probably have pads for an overkill number of caps and only stuff a few of them in the final shipping supply. Just for reference, here's a 500mA 5V switching supply from one of my designs. The footprint of this circuit is roughly 0.75" x 0.5" (as referenced by the 0.1" headers the circuit is tucked between).That Common Cathode diode in the upper right corner isn't even officially part of the switcher. It's just a "diode OR" of two possible input connectors.

Close, but I'd use surface mount flash and SRAM. No need for those huge DIP packages. Also I'd bring more of the PI-Zero down to the carrier board and put an Enet connector and possibly other useful stuff on the main carrier board(HDMI? Haven't checked to see what all the Pi-Zero makes available on the header connector). Also, more pins will make for a more stable Pi-Zero mounting. I'd probably also have standoffs to the Zero so you can "bolt it down". Alternatively, It could incorporate a DIMM connector for an R-PI Compute module as people seem to complain about the Zero's slow-ness. All Moot points as it appears there is no real market left and its unlikely people will want to keep buying the same thing over. And I need to stick to the small subset of things I actually want for my own machines so I can move on to that "next big thing" I alluded to above

So I just watched a video on the TiPi and thought "That's pretty cool. Don't know if I'd actually use it once the novelty wears off. But, what a mess of wires, stacked boards, external power adapters!" I feel like I could probably make a single board that combines the 32K sidecar, TiPi with whatever R-Pi zero "hat" circuitry is needed, and just has the Pi-Zero plug into it. So a single board that you just pop the Pi-Zero module onto and put it in a nice case. Also, with my new supply everything would just be powered when you switch the TI on. Of course I'm assuming the hardware and firmware of the TiPi adapter board is "open" and freely available. I could probably even make a high performance version that you pop that DIMM looking R-Pi "compute" module onto. Of course I'd change all of those large DIP components into much more compact, but not impossible to hand solder SOICs and possibly have components on both sides of the PCB. Still... I'm not saying I'm going to make this, but I'm not saying I wont Is this a thing that people(enough people) would want? Or is the existing, possibly saturated market for TiPi users already content with the current solution?

Looks like I figured out how to allow for lower than 12V input adapters without increased cost or complexity... My original parameters for the 12V was an input voltage range from +6V to +18V. This was suggesting Step-Up/Step-Down combo regulators which are complex and expensive. They also typically have low efficiencies in the 75% to 80% range(still better than the old linears, I'm sure, but...) Then I realized the way to make 12V is actually from my plentiful 5V switcher which is 90+% efficient! Also, a 5V to 12V 400mA boost regulator will be 86%-90% efficient depending on which IC controller I use(for about 20% more BOM cost, I can get the more efficient design). The cascade of near 90% efficiencies is pretty close to the lesser efficiency of the Step-up-down design, but much simpler and lower cost. In practice the combined efficiency of the 12V rail should be around 86% assuming there's not going to be much current drawn from it and no new hardware save oddball stuff that one might plug into the video connector is likely to increase the load by much, if anything. Normally, If I thought I needed a very clean +12V, I'd boost to, say 13.5V, and then put an low dropout, ultra low noise, linear regulator to 12V from that. However, it looks like the +12 is largely being used by fairly noisy digital circuits anyway(The CPU and RAM), so I suspect as long as I design for low current ripple(reasonable output capacitance should cover this), the 12V rail will be happy. Usually a rail like this is used in Audio/Video circuits for OpAmp bias and the like, but it appears that the bulk of the AV circuits use a balanced +/-5V dual supply, and the console creates filtered copies of those rails for the analog "branches" of the console circuitry. Again, I just need to cover current ripple since the 5V rail in particular is subject to constant switching loads(albeit at much lower frequencies than modern computers ned to handle). Again, a reasonable amount of bulk capacitance should handle the 3.6MHz switching transients... So, I've chosen the final candidates for all three rails and, thanks to TI's handy "WebBench" tool, I have the reference schematics for designs that should "just work" the first time as well! I may need to tweak the WebBench designs as they sometimes call out inductors that are not commonly stocked at DigiKey or Mouser, but that's usually not too big of a deal. I'm still a bit busy with other things, but I suspect once I get started, the schematic will only take a couple of hours and the layout should go fast as well. I'll just need to find a free weekend day to get this thing knocked out. Also, I want to get some reference measurements on my other two related projects to ensure I can reuse these designs on those as well.

Yeah... I gotta say this all seems a bit too niche for the additional effort. Unswitched power for a trickle converter to turn on the main power is one thing, but unswitched charging power means there would be twice as many high power 5V regulators on board. For switched power to an external Pi-Zero, I'll be providing extra capacity to the side port. I'm not sure what interface adapter is used for TIPI, but again, perhaps someone will do a design rev to allow the option to draw from the console(either with a jumper, or by "Diode-ORing" with low Vfwd Schottkys). As far as the next big thing? I'm working on my version of that. Hint it's not an interface or peripheral designed for vintage computers, but I think it will appeal to a lot of vintage aficionados. That's all I'm gonna say about that at the moment.