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Sinphaltimus

Personal 4 port cartridge expansion project

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So I made a ton of progress. tomorrow I solder the connectors. Before the end of next weekend it should be complete. although I may be able to start testing tomorrow before final assembly.

17554561_10208532438900447_387094684837617757240_10208532437820420_281023977425117636919_10208532436660391_7055640604278

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Finally got all the wires prepped. That's 36 4-way splitters complete. That's 180 solder points stripped, tinned and insulated. Now I can finally begin working on wiring it up.

17620116_10208543140247974_1957425138684

Edited by Sinphaltimus

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All the photos including today's work. Had to make a lot of modifications including extending all the GROM port pins so the connectors fit properly. All solder points tested and good. Except the wires which I will test one by one as I make the connections. Next up I have to solder the resistors in place. I'l probably do that tomorrow, I'm kind of spent most of the weekend working on this. Need to break for a bit.

>>>Public Facebook Album of Project<<<

Edited by Sinphaltimus

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I wired up up straight trough and connected a bunch of 90 degree adaprots so i could check each and every connection from console connector to GROM port. Grom 1 pin 2 and Grom 4 pin 24 are no good. So tomorrow I trace it down to the "open" and resolder each one of the two.

Tehn I connect the resistros and wire up the switches!

17546979_10208545515907364_6557129569167

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Oh - Hrm. I think facebook public pics are only public to facebookers? I dunno what's up with that. Guess I'll have to add them to an album here.

 

First I had to make a lot of modifications so I can use the connectors:

17620303_10208544694486829_8761905629747

 

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And then I had to extend all GROM port pins so the connectors would fit correctly:

 

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Put it all together...

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I wired them straight through first so I can test each connection.

17635198_10208545473026292_8592807201392

 

 

 

Out of 360 soldered connects, only 2 solder points need a looking at. I';; fix them theis week, then wire up the switches and resistors.

 

17546979_10208545515907364_6557129569167

Edited by Sinphaltimus

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Damn... that's a lot of wires!

I know, all because I don't know how to use circuit board software nor would I know how to design a PCB.

 

All things considered up to this point:

 

Out of 360 soldered connections, I have to investigate a issue with 2 of them. I say that's a Damn good outcome.

Edited by Sinphaltimus

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Oh - Hrm. I think facebook public pics are only public to facebookers? I dunno what's up with that.

 

I had that issue too, I uploaded tons of galleries only to learn nobody can see them without jumping through a ton of hoops.

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I know, all because I don't know how to use circuit board software nor would I know how to design a PCB.

 

All things considered up to this point:

 

Out of 360 soldered connections, I have to investigate a issue with 2 of them. I say that's a Damn good outcome.

since most of the connections are straight through you should be able to test from the main GROM port connection pin to the last GROM port connection pin for continuity and that would probably help diagnose it quick. You will not be able to do that with the pins connector to the resistors though.

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I fixed both issues. Ended up not being my handy work. It was faulty connections. The crimp at the connector end was on the insulation and not making contact. I replaced them and now all the straight through connections are perfect. Yes, made in China. Now I can continue with the resistors and switches connections. So psyched.

Edited by Sinphaltimus

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So this is big news. I have the switch box wired straight through just for this test. That means no switches or resistors are connected. All 4 ports are wired straight to the console connector so I cannot have more than one cartridge plugged in at a time.

The reasons for this is I wanted to ensure my wiring worked. I heard about issues with the FR99 and 16 inch GROM extension cable. I'm using an 8" GROM extension cable plus all my wiring, splits and soler points.

They all worked great, I used parsec to test and finally the FR99. They all worked so my next step is to wire it up for the switches and solder in the resistors.

This *WILL* be ready to show at FestWest. Can I call it the first ever 4-port cart expander for the TI-99/4a?

Port1 - CHECK.
post-47352-0-04883500-1491427395_thumb.jpg

 

 

Port2 - CHECK.
post-47352-0-79664800-1491427429_thumb.jpg

 

 

Port3 - CHECK.
post-47352-0-69352600-1491427468_thumb.jpg

 

 

Port4 - CHECK.

post-47352-0-06563000-1491427524_thumb.jpg

 

 

FR99 - CHECK.

post-47352-0-67787600-1491427590_thumb.jpg

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Well, I have several mutant 4-port and 6-port expanders here that someone in Germany made a long time ago, and I have seen one of the Mechatronic 8-port expanders. . .that said, yours is the first new port expander in a while :)

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OK, so it's not the first of it's kind. I can live with that.

Here's the updated schematic BTW.

post-47352-0-39041300-1491432261_thumb.png

EDIT:

Ksarul - do those other ones support uberGROM carts?

Edited by Sinphaltimus

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OK, so it's not the first of it's kind. I can live with that.

 

Here's the updated schematic BTW.

 

attachicon.gifDiagram6.png

 

EDIT:

 

Ksarul - do those other ones support uberGROM carts?

 

I have tested the UberGROM with the Navarone widget and I can tell you that if you have the UberGROM cart plugged in any slot it will take priority no matter what the selection is. At least with both of my Navarones it did.

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Right, that's the difference between the navarone and mine. Mine works with all carts allegedly. I'll be able to fully test at FestWest.

Edited by Sinphaltimus

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Allegedly.

 

post-12959-0-13590900-1491501331_thumb.jpg

 

More seriously, since it properly manages the select lines (which the Navarone does not - that was the whole problem), there are only a few conceivable cases that might still have issues:

 

-cartridges that use CRU feedback to the console (ie: SuperSpace should still be okay)

-cartridge combinations that draw enough current to overload the power supply (for instance, I wouldn't try to run 4 GRAM Krackers...)

-cartridges that do not honor the ROM or GROM select lines (I'm not aware of any but there are reasons it's possible)

 

A deselected cartridge on this switch will behave like a normal cartridge, it just never sees that it's being selected for data. It still has power and is still connected to the bus.

 

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Allegedly.

 

vader.jpg

 

More seriously, since it properly manages the select lines (which the Navarone does not - that was the whole problem), there are only a few conceivable cases that might still have issues:

 

-cartridges that use CRU feedback to the console (ie: SuperSpace should still be okay)

-cartridge combinations that draw enough current to overload the power supply (for instance, I wouldn't try to run 4 GRAM Krackers...)

-cartridges that do not honor the ROM or GROM select lines (I'm not aware of any but there are reasons it's possible)

 

A deselected cartridge on this switch will behave like a normal cartridge, it just never sees that it's being selected for data. It still has power and is still connected to the bus.

 

Well, I have plenty of positions available on these switches. I could simply cut power to unused carts. Would that be a good idea? I mean, if I simply cut power to the carts, would I even need resistors at that point? Cut the + and - 5v lines. As is, I'm cutting 3 lines now, I could cut upwards of 3 more. Edited by Sinphaltimus

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Well, I have plenty of positions available on these switches. I could simply cut power to unused carts. Would that be a good idea? I mean, if I simply cut power to the carts, would I even need resistors at that point? Cut the + and - 5v lines. As is, I'm cutting 3 lines now, I could cut upwards of 3 more.

 

No, because if you cut power but leave the data and address lines connected, the chips will attempt to draw power from them and thus crash the system. The only way to be 100% is 100% disconnection. What you are building will cover 99.9% and I defy you to find the 0.1% that fails. ;)

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No, because if you cut power but leave the data and address lines connected, the chips will attempt to draw power from them and thus crash the system. The only way to be 100% is 100% disconnection. What you are building will cover 99.9% and I defy you to find the 0.1% that fails. ;)

Good enough for me. I should have this completed and tested this afternoon sometime.

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Well I missed my goal because of some design changes again. I am certain it will all be wire up early tomorrow. I sure hope it works.. My concern is so many wires I had to add. And so much more soldering. Only thing left to do right now is wire up the console port to the groms and switches where needed. Resistors are in. I'll post updated pics when I'm done. I still have to do an album here.

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