Ksarul

A TI version was supposedly demonstrated at the 1983 CES, but I have never seen any traces of it other than the article that mentioned it (I think it was the IUG that mentioned it).

Not a good thing, dude. Stabbing your fingers is not a good thing. . .

I now have two of them assembled--except for the keycaps, as my keycap order is trapped in postal limbo somewhere in New Jersey. . . I am having lots of fun doing this though, as it gives me something productive to play with that can be done mostly anywhere (removing the random minor bits of excess plastic from the frames is really relaxing (except when I accidentally stab myself with one of my beading files, LOL)).

You really don't want to see my collection then, as his is about half the size of mine. . .She-Who-Must-Be-Obeyed is not amused at its existence either.

One note on the cartridge port: there is an oil-saturated felt hiding in the connector. They get really gunked up over time. If you remove the connector and extract the felt, you may clear the problem. The felt isn't needed--but when it is present it collects lots of metal bits over time and that makes it a problem waiting to happen.

Sort of like some of the snow goon victims from Calvin and Hobbes. . .

The keyboards were made by Mitsumi (or at least the two I have were). . .and many of them exhibit the same types of problems as the Mitsumi keyboards on the 99/4A, based on comments I've seen over the years. I know the keyboard was replaced on one of mine about 20 years ago using a spare the then-owner (Steve Eggers) received from somewhere, as it was having serious issues at the time.

I actually bought one of these about ten years ago because of its similarity to the MBX joysticks--and didn't know the background for its existence until now. Many thanks!

That mess is never a good thing to look at. . . .

There are probably between 10 and 20 of them scattered about within the community--and unknown examples pop up now and again. As to prices, you won't see one for less than $1,000 to $1,500, and possibly more, depending on who is hunting at the time. I have one that I bought several years ago. They do come up for sale now and again too--about once every year or two.

The 612 and the 688 are the two chips that have caused the most problems with the 100 or so boards I've built. BTW, you can use a 25LS2521 in place of the 74LS688, as it is an equivalent replacement (and in my experience, more stable).

Schematics are always useful--and I may actually have one of those PAL-N modulators with one of my Argentine consoles, so this one will definitely be helpful once you post it.

Do you have an EPROM burner with integrated LS logic testing capability? If you do, just pull the ones it can test one by one and see if any show up bad. . .

I have my first one mostly soldered together and in a nice blue frame. The frames require some careful adjustment to make everything fit perfectly, but that is expected with large parts like this as the materials used will always have a tiny bit of random shrinkage. The slot the circuit card slides into probably needs to be between five and ten thousandths of an inch wider and deeper, but with a little work, everything fits perfectly. I have to start working on the other three--one more in a blue frame, one in a red frame, and one in a beautiful bronze-brown frame. This project is a lot of fun. . .

One other thing I see--the square surface mount chip (1041036-1) has been replaced. Double-check all of the connections there, as the solder job looks a bit sloppy and the pins are really close together.

Yeah, that option is blocked for some reason. I just used the standard mode for him and said in the notes that there was nothing to ship.

I'd clean the edge contacts before you try anything else, some of them look pretty grungy. . .

One note: have you added the additional 32K RAM modification? You need it for any MDOS version after 2.50. . .

LOLOL, and now you know why I bid on this thing already. . .I'm still looking for a good ROM for it. I do plan to make a run of them, your request only moved it up in my project queue.

Looking at it, it is almost definitely for the HexBus Modem.

Looks like I may get to pick mine up tomorrow. . .

The extra schematics belong. . .

Don't forget the "Paper White" monitors. . .I used several of those at work back then.

I may have to open one of mine up to do a dump of the ROM. I'll see if I can pull one of the two I have out sometime in the near future. Also, on the W1/W2 jumpers, normally W2 (to ground) is connected. One other note: I thought I had seen the PAL equations somewhere, but they are not in the manual or with the schematics I have. The manual on WHT is also incomplete, as the programming appendices are missing.

I might just take you up on that--it sounds like it might be fun. . .