Date: Wed, 30 Apr 1997 14:35:12 -0400 (EDT) To: tghack-list@joyce.eng.yale.edu From: Keith Lee X-Software: MLF v2.3, Copyright 1995, 1996 by Bt X-Original-Id: <3.0.32.19970430133237.009c6db0@enteract.com> Subject: Breakthrough on modifying the PCE GT X-UIDL: 9abfe335e0c86229d8d97c3b16fc8d21 This grw out of a curiosity about the differences between the PCE GT and the Turbo Express. I am not bored or anything, I just need to do something strange and different every so often. I haven't heard of anyone modifying the PCE GT to be able to run US Hucards, so here is the run down: 1. The good news is that the Turbo Express and the PCE GT use the same logic board and keypad board. The difference is that the TE has one extra part and the connector board with the Hucard connector is wired with the data lines in reverse from the GT. Of course, we all know that you need to use a convertor or physically reverse the datalines in some other fashion.\ 2. The bad news is that the TE and the GT both have a metal shield over surface mount components. If you do not have steady hands and patience, don't even bother to try this. 3. Here are the steps: NOTE. USE PROPER STATIC CONTROL HANDLING TECHNIQUES. a. open the GT. There are 6 screws, 4 accessable fromthe exterior, 2 on the interior of the battery compartment. b. carefully open the case. you will notice 3 flex wire assemblies connected to the PCB attached to the REAR housing of the GT. Carefully remove these by rocking them side-to-side the long way (not flexing them back and forth!) BEFORE removing them, use a permanent marker to place a mark on the side of the flex cable facing away from the housing. This will allow you to correctly orient the cables when re-inserting them. The cables, for the curious, go to the following: DIN connector for the TV Tuner LCD Screen Connector Joypad Connector c. You will also notice 2 2-wire connectors on headers. Remove these. These are to: i. the battery terminals ii. the backlighting for the LCD display After removal, the two housing halves can be separated and laid flat. Untape the battery terminal wires from the shield and save the tape for later re-assembly. d. You will now work on the rear housing. One screw at the top left sector of the PCB holds the entire logic board in place. It should be a silver colored screw, similar to the screws removed from the battery compartment. Remove the screw and carefully lift the logic board out partially. e. Examining the connector PCB under the logic board will reveal 3 screws holding the connector PCB in place. Remove these and lift the logic board with the attached connector PCB. f. The logic board has a metal shield on both sides. You must remove the shield can on the side that normally faces the bottom of the housing first, then remove the top shield can. This is how you do it: i. Using a medium wattage, and small-to-medium tip soldering iron, heat up the "legs" of the shield can from the side opposite the one the shield can is mounted on. Use a flat jeweler's screwdriver to slowly leverage the center and ends of one side out. ii. Do not expect to get it out in one pass. Reheat each solder joint while lifting the shield can slightly each time. iii.Use a solder sucker to clean the solder from the hole and make sure that the legs of the shield can are relatively free of solder. g. Remove the remaining shield can in the same way. one corner will be partially or fully covered with silicone RTV compound. You may safely heat the solder pad underneath the RTV compound by using your soldering iron to push the material slightly to the side. This is the last leg of the shield can that I loosened. h. Orient the PCB with the top side facing you (the side you removed the last shield can from). It will have printed legends at the top for USA and JPN. A red mark will be in a white box by the lettering "JPN". Locate the HC6280 chip on the right side, top chip in the middle. Above this chip are 3 surface-mount resistor pads, with 2 pads occupied, and the third, right-most, empty. i. This third set of pads is normally occupied by a zero ohm SMT jumper. By accumulating a small ball of solder on the tip of your soldering iron while near these pads, it is possible to carefully bridge the pads with a drop of solder. If you have no experience doing this, just get a piece of thin stripped wire-wrap wire and bridge the pads, making sure to cut the wire close enough to the pads to prevent shorting to other components. j. Put the shield cans back, soldering them in the reverse order that you removed them. k. Put the connector PCB back and secure with the 3 screws previously removed. If you forgot which holes they go into (there are 4 holes, but only 3 screws) they appear like this: --------------------- | TOP OF PCB | | | Connector PCB as Seen From Above | | | S S | | | | | | S | --------------------- l. Put the logic board back into the housing, making sure to secure it with a silver screw. m. Using a rocking motion, reattach the flex cables to the appropriate connectors. You will need to hold the two halves slightly together when doing this, since the flex cables are too short to leave the housing open. At the same time, reattach the battery terminal connector and the LCD backlighting connector. Note that you cannot mix any of the connectors up, since each is a different size or shape. Re-apply the tape securing the battery terminal wires. n. Close the housing, securing it with the 4 black screws accessable from the outside and the 2 silver screws accessable from inside the battery compartment. o. You are done. 4. My observations: This takes about 15 minutes for a skilled person, 45 for a novice with some soldering experience. The technique is reversable, and does not alter the normal functioning. I used a big tipped soldering iron because it was all I had at home. Therefore, this is not really a big deal to perform. I used a cheesy purple convertor to test. Does this convertor work in anything without modification? Probably not. I had to cut the notch bigger, since the GT power switch has a lock that prevents removal of the Hucard when it's ON. I was lazy and made big notch in my convertor. You can carefully cut an "L" into the convertor so that it can't be removed in the ON power position. I performed this modification on the kitchen table in about 20 minutes, and most of that was spent waiting for the soldering iron to warm up. I suppose that since most everyone has a Turbo Express, this is pretty esoteric. I have 3 GTs and one Express, so I felt the need... Incidentally, the unit I modified is up for sale. I'm open to offers, especially trades. I have successfully performed modifications to the PCE DUO and SuperGrafx units also (not this easy!). If you need help, email me. If you just want it done, email me...I'm open for some supplemental income. Bt: you have my blessings on immortalizing this procedure into a FAQ or whatever on the TGhack server. Just put my name on it. Hope this helps you all....Please leave comments. Keith Lee megamind@enteract.com