Excerpted from my hacklist message of Fri, 2 Aug 1996: Never let it be said that I never do anything for the list. :) I finally completed my trace of the "expansion bus" on the PC Engine. Configure your reader or text editor to view this diagram with a monospaced font, otherwise it probably won't align correctly. It's a 69 pin connector, 3 rows of 23 pins each. Diagram from the back of the PC Engine/TurboGrafx, right side up: AR GG 01 VM 32 30 27 GG 17 20 22 23 13 11 10 08 GG 05 03 GG VV VN VR 02 CD 35 34 VU 29 26 15 19 21 VJ 14 12 VG 09 07 06 04 24 VT 37 36 VP AL VV VS 33 31 28 25 16 VL VK QQ VI VH QQ VF VE VD VC VB VA GG VZ VQ The signals that are important for tapping the stereo audio, NTSC video, and NTSC RGB signals from the unit are: AR -- Audio Right AL -- Audio Left VZ -- External composite video, connected to R145. Note -- this may need to be externally bypassed to ground with a capacitor to use directly as a video feed. Also used as a vertical sync signal for RGB connections. GG -- Ground VR -- Blue RGB signal VP -- Green RGB signal VQ -- Red RGB signal VN -- Horizontal sync signal To connect the PCE or Turbo to a standard television set or VCR, use the following pin connections: AR and GG \ Connect these to RCA cables, ground going to the "shield" or -- outer metal wrapping, and AR or AL going to the "signal" or AL and GG / center pin. These plug directly into your Audio In R/L on your TV or VCR. VZ and GG -- Similarly, connect GG to the "shield" and VZ to the "signal" of an RCA cable. This connects to the Video In on your TV or VCR. For a clearer picture, connect a 0.1 uF capacitor between the two terminals on the side of the cable that connects to the PCE/Turbo. VR/VP/VQ/VN -- If you have an older RGB monitor capable of horizontal sync at NTSC frequencies (around 15 kHz), you can use it as a monitor for your PCE/Turbo. Connect VR, VP, and VQ to the blue, green, and red inputs of the monitor. Connect VN to the horizontal sync input, and VZ to the vertical sync input. If the monitor only has a single sync input, use VZ. You should have an incredibly clear, crisp picture! NOTE -- Most modern monitors will *NOT* sync this slowly. Monitors of the "Sony Multisync" variety of old (e.g. the "2A") are capable of syncing to these frequencies. Also, monitors marked as "Amiga Compatible" should sync to the NTSC frequency as well. Note: Many people have asked how to get these signals off of that connector. The easiest way is to get your hands on some single pin headers. They are small, black pieces of plastic with a wire coming out of the other side. They are sockets that accept a single pin. Using 4 of these, you can tap all of the signals necessary to get both stereo audio and video from a PCE/Turbo. If you can't find any pin headers (I'm trying to track down a source for ordering them), you can also cut up ribbon connectors, the kind you might use to connect a floppy or hard drive in your PC/Mac. Using a strong pair of diagonal cutters, simply CUT the cable connector. If you're really accurate in your cutting, you can make dual-pin header cables (a single column of 2 pin headers and the wires that attach to them). It's not easy to get the cuts just right, but it's a cheap solution for many. (I have about 10 extra ribbon cables just lying around.) No matter which of these two methods you use, you can purchase RCA cables and connectors from Radio Shack (or other local electronics shop) to complete the cable to your VCR or TV. If you're feeling cheap, you can also cut an RCA cable in half to form 2 RCA -> wire connectors. Then, just splice the bare ends to the pin headers from above, and you've got a pin header <-> RCA cable. Good luck, Joe --- - Joseph LoCicero, IV jolo@ece.cmu.edu http://joyce.eng.yale.edu/~jolo - - A supporter of Inet Free Speech, OS/2, OpenDoc, and Cadence CAD tools - - The freedom of a society is proportional to how much its people laugh. - - - Zero Mostel -