hi guys i am new here and i really need your help. i was trying to do the vga mod and i accidentally burn the solder point for v-sync it wont take any solder i searched for the pinout and found the that it is the 8th pin from left to right on the video connector port but the pins are to close together and it is out of my ability to solder there is any place else where i can tap the v-sync.
well i think i have found where to tap the v-sync but am not 100% sure here is a pic. sorry for the bad quality its from my phone. well i found the pinout for the a\v port ant it says that v-sync is the 8th pin from left to rght but the pns are too close together. i followed the trace and i believe it croms that transistor. but i am not sure. any help would be appreciated.
If you look below the video socket, there is a 3-pin component in a SOT-23 package marked "ZD603" that contains a pair of protection diodes - the vsync signal is on pin 1 (with the single pin at the top and the two pins facing down, it's the pin on the lower right).
thanks guys for your time i solderd v-sync to the right pin of the zd603 transistor but i am getting audio but no signal on vga i tried on a pc lcd montor and two tv's. if i toggle the switch in the back it does change from composite to vga but no signal on vga.
Either you've got the wrong point or you've trashed something. Hard to say without looking at it but usually this stuff is fixable.
All I can suggest is that you recheck your connections - the point you have wired to is the correct one for vsync. It's also worth checking that you have the mode lines hooked up correctly - if you just have one of them them the unit might be switching into RGB mode and attempting to drive the monitor at a rate it can't handle. Another thing to check is how the monitor behaves - does it go into power saving mode or display any messages about the input signal? Edit: OK, I just did a double check on a board I have sitting here (VA1) and that point on ZD603 is correct - the left pin has HSYNC and the right pin has VSYNC.
well i think i may have found the problem i followed mmmonkeys schematics and read that the resistors are inverted the 150ohm resistors should be the first thing next to h-sync and v-sync tomorrow i am going to swap it and see what happens.
So you have the 150R resistors going to VCC and the 4K7s in series with the sync signals? That would certainly stop it from working since it would attenuate the sync signal to a fraction of a volt.
well still no luck. i did some test on my 15khz arcade monitor and the results where a little weird. if i bridged 1 of the rgb and vga points i get a jumpy black screen but i can make out the dreamcast logo if i bridge both of them i get a jumpy black screen but nothing else the monitor tries to sync but nothing else. on my pc screen i get nothng it just goes to sleep and i know my pc monitor can handle the resolution because use to use quickres and it would display nicely. composite works normal but still no vga and i am out of ideas.
