View Full Version : question with TI-99/4A

April 21st, 2007, 01:08 PM
im not sure if this will work on my tv. the video cable has like 2 pronged thing iver never seen b4. my tv is pretty new as well. is there a diffrent video cable i can use.

April 21st, 2007, 02:02 PM
ithe video cable has like 2 pronged thing iver never seen b4.

Right. You're describing an RF switch box that's meant for older TV sets which had 2 screws for the antenna terminal. I guess your TV probably has a connector (marked "Antenna" or "Cable" or "RF") that looks like something should screw onto it, right?

The only photo I could find makes it look like that box is part of the rest of the cable. I'm interested to see what the other end of the cable looks like. Assuming it's an "RCA" or "phono" plug, it will look like it fits the "video" connector on your TV, and then the solution is easy: you'll need a long cable with an RCA/phono male connector on both ends and an adapter for your antenna jack (called an "F" connector) which has an RCA/phono female and an "F" male, like Radio Shack part #278-255 or similar.

Then all you do is: connect one end of the cable to the "RF out" of the computer, put the "F" to "RCA/phono" adapter on your TV's Antenna/Cable/RF jack, plug the other end of the cable into the adapter, tune your TV to channel 3 and turn on the computer. (If you don't get a picture, you might need to tune to channel 4).

Let us know how it goes. That sounds like a decent haul for five bucks.


April 21st, 2007, 02:42 PM
Moved to the TI specific area.

April 21st, 2007, 06:04 PM
In addition to what ahm wrote, if the output cable and/or the switchbox can't be disconnected, then you will need a 300 ohm to 75 ohm converter. It will have screw terminals on one end where you will connect the output of the switchbox, and an F connector on the other end that will fit into your tv's ANT/Cable/Coax input jack. If you're in the US, the converter (or adapter it may be called) can be found at Wal Mart or Radio Shack.


April 21st, 2007, 06:29 PM
Here's a typical game switchbox.

The game plugs into the right side of the box using an RCA plug.

The antenna (or tv cable) connects to the left side, using either 300 ohm twinlead or 75 ohm coax F connector.

The box attaches to the tv using the 300 ohm twinlead pigtail coming out of the bottom. If you tv accepts only coax, then the adapter (just to the left of the pigtail) should be connected (note that this particular pigtail has a spade connector missing).

The gold adapter to the left (between the RCA cable and switchbox) is a female RCA to Male F adapter. If your TI output cable has an RCA plug, use this adapter to plug the cable directly into the tv. I got this particular adapter at Radio Shack.

If you want to use the switchbox, or the cable doesn't disconnect from the box, use the 300/75 ohm adapter to connect to your tv.

Hope this helps you get your TI in operation.


April 21st, 2007, 06:53 PM
I just realized that I don't know anyone with a 99/4A. Now I think I know why :-)

It seems that the "switchbox" is actually an RF modulator and it doesn't come off the cable.
Seems a shame to have to slap a 300 ohm to 72 ohm adapter on there as well, but that would work.

If you're up for a little soldering, the comp.sys.ti FAQ (http://www.99er.net/tifaq.html) has a pointer to a site that explains how to make your own video cable (http://web.archive.org/web/20011206043839/http://www.nwlink.com/~theraven/ti994a/dinplug.htm).

Terry Yager
April 21st, 2007, 07:22 PM
Yes, the TI's RF mod has an attached cable that terminates with a 5-pin DIN connector which jacks into the console unit, and a dual-lead connector which is attached to the antenna connector of an old-skool tv set. For today's TVs, you need an adaptor which costs a couple of buck$ at RatShack, etc.


April 30th, 2007, 05:11 AM
See my note in the other thread on this subject--it is really easy to build a cable to eliminate the RF modulator entirely. . .