The Great TV Hack of '01 or Hacking a $100 TV into an arcade monitor

Preface

While we were building the cocktail table we had the idea that a 19 inch TV might be able to be converted into a cheap arcade monitor. We went to Fry's and found the cheapest 19" TV and bought it. Then we hacked it all up and got it working as an arcade monitor for several classic games. Then we went back to Fry's and bought 5 more (Also known as "three shopping carts worth").

So I finally decided to put this info on a web page because I get asked how we did this quite often! :-). What follows are bits and pieces from several emails I wrote to people explaining what we did. So if it seems a little disjointed, that is why :-)...

Important!

You should be afraid of TVs. They generate upwards of 20,000 volts which can at best knock you flat on your back, and at worst kill you. Don't mess around with the insides of a TV unless you know what you are doing. And don't complain to me if you kill yourself (I suppose that's not really possible :-), but you get the point).

The Hack:

We hooked up the RGB outputs from the game board right to the guns on the back of the CRT. We needed pull-up resistors on the lines so the picture was bright enough (the games couldn't drive the guns directly--way to dim). Then we cut the signals that the TV normally drove the guns with. Then we fed the composite sync signal into a composite input on the main chip inside the TV (there was no RCA composite connector on the back of the TV). That composite input (luckily) syncs to the raw sync signal and sets up all the scan rates correctly.

We got the repair manuals for the TV from the manufacturer which included a schematic and that was very helpful.

I made a little bread board that had the pull-up resistors on it and a rotary switch so we could switch between composite, RGB and normal TV operation. The board had a standard arcade monitor connector, an RCA plug (for composite), and power. Its output went to various parts of the TV to enable all the modes.

More on composite sync:

We found a composite video input on the TV chip and put the mixed horiz and vert syncs into the composite video input. Since composite video has the same kind of syncs as the composite sync that comes out of the arcade board the TV chip was able to sync up to it. Then the chip set up all the scan rates to the sync signal so that the RGB that we were force-feeding the guns would be in sync.

The only problem is that a couple of my arcade boards (raiden 2 and raiden 1) have a weird vertical refresh rate (65 Hz) which is too far out of range for the TV chip to sync to. So they don't work :-(. A normal arcade monitor works fine with these (it has analog adjustments that have a very wide range).

Mounting it:

What's great is that the TVs have the same mounts on the corners of the picture tubes as normal arcade monitors, so it's pretty much a drop in replacement. Then the only trick is mounting the TV's PCB. We ended up extracting the TV enclosure plastic where the PCB normally screwed into. We used a table saw for the extraction. :-) I wish we took pictures of us sawing a big piece of plastic, it was crazy! But the PCB mounted just great because thats where it was meant to mount. We just screwed it in to some big wood blocks we had on the underside of the cabinets top, right by the monitor.