Can the QI console be "fixed"?

[iKarith]

I understand the QI console contains a few "improvements" in terms of not playing AtariSoft carts. I also know the power supply connector on the back is different (but still compatible with the old transformer.) Were there other actual changes from over the non-QI beige console? Were any of them actually improvements? And can one of these consoles be "fixed" to be compatible with the full range of software?

[+Schmitzi]

oh, what is "different on the supply connector" ? "Transformer" means the power-brick ?

 

Do you mean I can differ between QI and not.QI by looking at the power-in-plug ??

 

(I know there are some color-differences on the sideport, maybe you mean that ?)

 

xXx

[iKarith]

The QI will often have a two-pin power connector instead of four pin. It works with the same transformer, but has fewer pins. Older consoles could possibly have this power supply because of a repair, and I'm not sure all QIs have it, but I'm basically asking if anything was done to actually improve quality of the QI version, aside from locking out Atari games and using fewer chips. Like, were bugs fixed or anything, or was it purely hardware?

 

And (especially if the answer is that the only software change is the lockout), what does one do about the Atari games?

[+mizapf]

The QI console does not lead the CRU lines to the cartridge port, i.e. cartridges with CRU control (e.g. for banking) won't work at all.

 

The only thing about the Atari games is that the menu setup does not look at 6000. So these games could be started by a simple machine language program that finds the pointer for the branch.

 

The mainboard is quite different with some custom chips that contain the TTL-based logic.

[iKarith]

Am I to understand that these are two different problems? Lines missing on the cartridge port sounds like something you fix with a bit of wire and some solder on the underside of the board to connect the missing signals to the necessary pins. But the other issue sounds like a ROM problem.

 

As I understand it, the TI's ROMs are GROMs, which are a thing that don't really exist anymore. You'd need a conventional EEPROM and some glue logic including a counter on a carrier board to replace that. Or you I guess you just use a microcontroller as a GROM emulator or something? Maybe not easily since the TI's clock speed is a little strange. I suspect this problem has been solved in my XB 2.7 cart, but I dunno if it's been solved in the console to replace the system ROM?

[+jedimatt42]

I thought I had read that people have repaired QI ROM only/Atari cart issues by swapping the OS ROM chips. But I have never seen any write-up on the procedure. ???

 

Was that a real practice at one time?

 

-M@

[+Ksarul]

If you have a dead non-QI console, it is a trivial matter to put the non-QI GROMs into the GROM sockets on the QI board, which solves all of the issues between board versions with the exception of the CRU line missing from the cartridge port. This was done pretty regularly BITD, and there was quite a bit of crazy overlap back then when TI was assembling consoles too (non-QI boards with QI chips or QI boards with non-QI chips).

[globeron]

There are two type of QI. V2.2 from 1983 cannot operate the 3rd party cartridges

QI with 1981 is. Can do all. Inside hardware is different a D recognizably at the

Side port with silver springs and are beige TI.

There should be table somewhere last time we sorted it out.

[+mizapf]

Am I to understand that these are two different problems? Lines missing on the cartridge port sounds like something you fix with a bit of wire and some solder on the underside of the board to connect the missing signals to the necessary pins. But the other issue sounds like a ROM problem.

 

You should be able to add the CRU lines with some soldering work, but such work is definitely needed.

 

The second problem is not really a big problem.

 

There is a search procedure in the console which checks for headers at the GROM start locations, i.e. at 6000, 8000, A000, C000, E000. In the classic consoles, it continues to search for a header at the address 6000 in CPU address space. In the QI console this last step had been removed.

 

You do not need GROMs to run a cartridge, neither in a QI console. Its header is not checked, so it does not appear in the menu list. But the ROM contents are still there, you just have to find the pointer by yourself and do a branch to that address.

 

For instance, the Defender cartridge starts like this:

6000: aa01 0000 0000 600c 0000 0000 0000 6072  ......`.......`r
6010: 0844 4546 454e 4445 5202 bb5a 305f ee3d  .DEFENDER..Z0_.=

You see that at 6006 there is a pointer to 600c, where you find a NIL next pointer, then the pointer to the program at 6072, then the name. Accordingly, to start Defender, you should write a machine program with a B @>6072.

 

You cannot "fix" it by hardware but by a small assembly language helper tool. The problem would be ultimately to load and run this program. So you either have a HFDC or another disk controller which adds assembly language calls to BASIC (CALL ILR, CALL LR, CALL LLR), or you'd have to load via Editor/Assembler, run it, swap cartridges without resetting the console, and then hope you tool has survived the swap.

 

Finally, you could use the LOAD interrupt. Using Editor/Assembler, you upload your cartridge support into RAM, install the LOAD vector, swap cartridges with or without reset, press LOAD and then have access to the cartridge.

Edited June 11, 2016 by mizapf

[+Ksarul]

Michael's method works perfectly for those without a spare set of the original GROMs--but if you do have a set of the 1981 GROMs, just replace the V2.2 GROMs with them and be done with it. . .or find one of the very hard to find GROM busters for the side port and use that to launch the ROM-only cartridges (it basically does what Michael is explaining, but using a hardware dongle to execute the hook).

[iKarith]

That sounds like (intentionally) too much work. This prompts the question: How does one create new GROMs? That's a more advanced question, and I don't need the answer to that except purely for the sake of curiosity. I haven't got a QI console, though at some point I'd like to take pictures of one before, during, and after GROM "downgrade" and CRU signal adding for documentation purposes. Could be a fun project besides.

 

Are the QI models considered "collectable" compared to the others because they're less common, or are they considered undesirable because they're annoying? Or something else?

[+Ksarul]

On QI models, the answer is all of the above. . .they are relatively uncommon, which makes them a bit more collectable for some folks, but they are also a complete pain, so a lot of other folks avoid them like the plague. One thing that is true no matter what: they are probably the most stable motherboard TI produced--although that just puts them in the category of the best in a very good group, as all of the motherboards were rock solid.

 

In answer to your GROM question, you could put a daughter board in there with an UberGROm chip on it. Tursi has the functionality to override console GROMs blocked right now, but his software is capable of emulating any of the TI GROMs. Just put in the daughter board programmed with the contents of GROMs 0, 1, and 2 in the flavor you are looking for and you'll be able to operate without any problems. . .although you may have to add a forced clock increment element to the daughter board, as the current UberGROM depends on the console GROMs to stay in lockstep with the console.

[dphirschler]

There are two type of QI. V2.2 from 1983 cannot operate the 3rd party cartridges

QI with 1981 is. Can do all. Inside hardware is different a D recognizably at the

Side port with silver springs and are beige TI.

There should be table somewhere last time we sorted it out.

I have one of these 1981 QI consoles. I believe OLD_CS1 has one too. I consider myself lucky to have my QI console. It is also unusual because the normal blue stripe on the power switch is red on mine.

 

Darryl

Edited June 11, 2016 by dphirschler

[globeron]

I have the same here beige QI (silver springs at the port at right side of the console) and red indicator

and a normal beige (copper springs at the port) and a blue indicator (this one I converted into an FPGA model)

 

but I still want to make that led (as you cannot see visually see if it is on or off), I saw the "hack" somewhere.

(the silver / black has the led, but the power on/off button is a bit difficult to use).

[dphirschler]

I think I made a thread about the LED mod. Here--> http://atariage.com/forums/topic/228592-beige-console-power-led-mod/

 

Darryl

[+remowilliams]

Interesting, I didn't know about the QI version of the beige console before. I've got a lovely beige one that I swapped GROM into but it has the brass connectors.

[senior_falcon]

There is a thread called "Bypass V2.2 protection" in theTI-99/4A Development department. Post #27 has a short program that will run in TI BASIC and provide a menu of programs in the cartridge ROM. You should read all the posts for more information.

[+OLD CS1]

I now have four beige consoles, all of which have the original, non-2.2, OS. I am actually surprised to have accumulated so many considering how many 2.2 units I have been able to identified on eBay. But this just-so happened.

[Gary from OPA]

For a while after 1983 TI infact sold the original GROM's you could buy a v1.1 and install it replacing the fucked-up non-ROM searching GROM in the QI's consoles.

 

There is only 3 ways to fix up the QI:

 

1: Replace GROM 0 with the better earlier GROM that does ROM searching.

 

2: Use a GRAM-Kracker or P-Gram or Pop-Cart or S.O.B. device to override GROM 0.

 

3: Try one of third-party tricks that can launch >6000 based ROM's even with the newer GROM instead.

 

Other then that, the QI is infact nice to own, it does not heat up as much, is more stable, and is very nice motherboard inside, the latest and best of TI99 even tho it pushed out the illegal third-party cartridge makers that were not coughing up license fees to TI for their software publishing rights!

 

Yeah, also the CRU Logic to the Cartridge Port is missing, but very few used it, just Databotics and me with Pop-Cart, it was really not in the official published TI docs for Solid-State-Software.

 

BTW, there is later models of the TI99/QI that are even worse with the v2.4 GROM 0 -- But most of the changes in those were for non-english support!

Edited June 12, 2016 by Gary from OPA

[+Ksarul]

Is there a good dump of the V2.4 GROMs anywhere, Gary? It would be good to be able to add those to MESS/MAME. I take it that this GROM 0 is also different from the one for the Control Data consoles. . .

[RXB]

I am using SOB and I have always love it!

[iKarith]

Well, I've kinda decided that at some point I would like a QI model for the purposes of "fixing" it with lots of pictures. I suppose it's easy enough to find a machine whose power supply or keyboard or something has gone kaput that I could snag its GROM without too much guilt, though since I am reminded every so often that within the next decade or so all those Atari VCS carts are going to fail en masse, the idea of adapting Tursi's work for replacing system GROM is definitely something to think about.

 

In fact that could make the QI motherboard at least a bit more desirable for folks, if they didn't have to worry about what came in the GROM socket and we document an easy CRU fix. Looks like we'd need just two jumper wires--and there's probably a couple of places to pull the signals from.

[Tursi]

Just put in the daughter board programmed with the contents of GROMs 0, 1, and 2 in the flavor you are looking for and you'll be able to operate without any problems. . .although you may have to add a forced clock increment element to the daughter board, as the current UberGROM depends on the console GROMs to stay in lockstep with the console.

Or just talk to Tursi since it's a software lockout that adds this requirement, not hardware. I didn't want uberGROM carts to accidentally conflict with the console GROMs, and the addressing code needs a little more testing. It'll be released with MPD.

[iKarith]

Or just talk to Tursi since it's a software lockout that adds this requirement, not hardware. I didn't want uberGROM carts to accidentally conflict with the console GROMs, and the addressing code needs a little more testing. It'll be released with MPD.

 

Tursi, if I every come across a QI machine that happens to have 2.2, would you be up to working with me to cook up a GROM replacement for it? As I said, I'm contemplating the future when we might all need to replace those chips.

[+OLD CS1]

Bring up a question in my mind: does GROM performance drop over time, and if so is it perceptible?