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F18A Video Board and QI Motherboards/Systems


rickneff68

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Just an FYI if you own a beige QI motherboard and purchase a F18A video board. The VDP RAM (and related electronics) prevents the board from sitting evenly in the slot. However, this is easily fixed with any 40-pin socket (see pictures) or, possibly, the ColecoVisi​on, tall pins version. (I'm not sure of the latter as I don't have a tall pin version of the F18A.)

 

This might have been mentioned previously somewhere, but after doing some searching here and on the http://codehackcreate.com site, I didn't see any mention of this. If this has been mentioned before, I apologize for reposting.

 

And, if you do have a QI board, you don't have to worry about the additional height as there is only the heat shield on the bottom of the motherboard. Plenty of room up top for the socket and F18A board!

 

Just some pictures showing my configuration after adding a 40-pin socket.

post-51432-0-11674300-1494899737_thumb.jpg

post-51432-0-09922500-1494899743_thumb.jpg

Edited by rickneff68
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Thanks for the photos and info! I have never seen a QI console and did not know they were *that* different. In this case, yes, the tall pins option would probably have worked better. This is a problem in some other systems too. Since the F18A is lopsided, there will always be systems where it is simply the wrong way to work very well.

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I was surprised there was such a significant difference as well. But fortunately, it's easily resolved.

 

It might be worthwhile to make a note about it somewhere on the order page. Feel free to use any of my pictures if you want.

Edited by rickneff68
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I have a beige model and I didn't have any issue with the F18A sitting unevenly. It sits perfectly even. Maybe you have a cost reduced model? Does it say "V2.2" on the title screen when you turn it on? If so, ditch it and get a normal model ;)

 

The QI model is the later model which has a different motherboard layout. Hence the need for the socket to rise the board up a bit. Mainbyte has a good picture that shows the different layout between the two boards: http://www.mainbyte.com/ti99/computers/ti99qi.html

 

Oddly enough, the QI model I have doesn't have the V2.2 OS -- It still shows the 1981 copywrite and runs 3rd party modules, but the hardware is quite different.

 

Also, I have 4 TI-99/4A consoles, so I think I'm fine.

Edited by rickneff68
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Interesting that it does not have v2.2. Very cool! Yup, my beige model had the original MB inside. Someone should set up a FAQ displaying both boards for people looking to upgrade to the F18A...and someone should test the tall pin version on it. That way people can select to order to tall pin version for this newer board (assuming it fits) or the short pin model for the original board.

Edited by eightbit
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The QI model is the later model which has a different motherboard layout. Hence the need for the socket to rise the board up a bit. Mainbyte has a good picture that shows the different layout between the two boards: http://www.mainbyte.com/ti99/computers/ti99qi.html

 

Oddly enough, the QI model I have doesn't have the V2.2 OS -- It still shows the 1981 copywrite and runs 3rd party modules, but the hardware is quite different.

 

Also, I have 4 TI-99/4A consoles, so I think I'm fine.

I believe that the original groms could be used in the Q1, making it compatible. This one has probably been through that procedure, in the past. I have a couple of the Q1 motherboards,that I was going to do the same thing on in the future..

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I believe that the original groms could be used in the Q1, making it compatible. This one has probably been through that procedure, in the past. I have a couple of the Q1 motherboards,that I was going to do the same thing on in the future..

 

I'm sure they can, but I doubt this system has been modified. According to the Mainbyte page, just because it was a QI board doesn't mean it always had v2.2. I wouldn't have minded if this one did as I'd be curious to try to replace the GROMs in it.

 

Just a bit of history on this system, I bought it off eBay cheap as it was listed as parts/repair due to a VDP RAM issue. I specifically bought this system to mod and tinker with. I'm finding as I'm working on projects that the board layout does affect some of the projects that others have posted or are written on other sites. So, I may start a series of posts outlining some of the differences for those that have QI boards.

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  • 3 weeks later...

I've been talking on FaceySpace about my interest in the idea of a pin-compatible GROM chip replacement, possibly made out of a small microcontroller with enough pins. It'd be kind of a waste of the microcontroller to replace a settable counter, a tiny (by today's standards) ROM, and a couple of basic gates, but the fact is that size and cost for those things would be more than the microcontroller. :)

I figure a drop-in GROM might be useful for developers as well, and who knows how long the original GROMs will last anyway? Still, if you wind up with 2.2 on a console, just swap the GROMs and you're good to go unless you have a QI board. There'd be no more need to try and forage for dead consoles to raid chips from. And if you do have a QI, all you'd need to do to properly "unimprove" it with a GROM replacement is to wire CRU to the cart port as well, but that's soldering most people can probably manage with some instruction.

 

For these reasons, I'm kind of looking for a QI board at some point.

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I've been talking on FaceySpace about my interest in the idea of a pin-compatible GROM chip replacement, possibly made out of a small microcontroller with enough pins. It'd be kind of a waste of the microcontroller to replace a settable counter, a tiny (by today's standards) ROM, and a couple of basic gates, but the fact is that size and cost for those things would be more than the microcontroller. :)

 

I figure a drop-in GROM might be useful for developers as well, and who knows how long the original GROMs will last anyway? Still, if you wind up with 2.2 on a console, just swap the GROMs and you're good to go unless you have a QI board. There'd be no more need to try and forage for dead consoles to raid chips from. And if you do have a QI, all you'd need to do to properly "unimprove" it with a GROM replacement is to wire CRU to the cart port as well, but that's soldering most people can probably manage with some instruction.

 

 

That was what I wanted with my AVR-based GROM, but the DIP AVRs don't have a compatible pinout. It'd be trivial to take one of the PLCC packaged AVRs and mount it on a small PCB, though, you'd probably get pretty close to the same size.

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