Hello, As you can see I am new here and have been enjoying reading many topics over the last couple of days. I'm looking for some knowledgeable people to help me out with a query. I have just purchased a Core Grafx II console but it looks to have had a fairly decent RF conversion with a small RF Unit and PCB in place of the Din output. Now the unit works fine, I can get a picture but it has very low sound and also looks to be outputting 50hz due to the borders top and bottom. It seems to have the RGB points from the Ext bus tapped to the small RF PCB. I wondered if this was originally destined or converted for the Korean market but I can't find any references on the net about this particular conversion at all? I do want to convert it to RGB, which I assume is possible and also restore the sound but any ideas on the 50hz problem? Would it have had the crystal changed in this case such as I have read about the PAL Turbografx? I will provide some internal pictures shortly if anybody is kind enough to help me out with anymore info. Many thanks, Jonny
Update As an update to my earlier post, I've noticed that the crystal is 21.XXXmhz which seems to indicate NTSC rather than PAL by my research. I'm a little more confused now. Any ideas? Jonny
RGB Mod Hi Assembler, that is my aim, however there are so many stray wires, including the one linked to a small resistor that has been soldered together and I'm wondering if this would need to be cut or is on standard consoles? Any idea if just removing all of these connections and doing the RGB Mod would work or is it a 'suck it and see' job? I have seen pics of the white original engine and it's RF modulator but doesn't seem to include this PCB. I can see 'NEC' branded chips on the underside which made me think it is a standard conversion but the wiring doesn't look too professional. Any expertise on the 50hz/60hz problem? Thanks, Jon
Core Grafx II Conversion Complete Hi again, whether it be of any interest, I thought in order to complete this thread I'd post the outcome of my work. I removed the RF Unit from the board and desoldered all points, I found a sticker on one end which did confirm a PAL-50hz output: I then proceeded to install an 8 pin DIN socket and wired it to take the RGB signals from the expansion bus: Made up an RGB Scart to 8 pin DIN lead and upon testing, found I did indeed now have the 60hz signal back and clean RGB output: Jonny
How about some pics of the RF board's top? This should be an unofficial conversion for the HK market. Probably it originally output PAL60 because it's kind of difficult to halt the VDP for 50Hz (there are Famicom conversion boards which can though).
RF Hi, I shall update the thread with a top down view of the board tomorrow morning GMT for you. It most definitely was running 50hz with large borders top and bottom, this immediately reverted once I'd removed and made the conversion. Jonny
Makes me wonder what is that NEC MK5060 part. Google found nothing but Chinese people who wanted to sell it.
It is not a true NEC part; MK = Makko = Bung. Makko is also silk-screened on the PCB. If you were going to throw it out, I'd gladly take it to go with my Famicom! The ASIC should be very similar if not identical to the Famicom one, it will synchronize to the display and extend Vblank 30 odd lines. Here's my FC: http://img258.imageshack.us/img258/2925/p1010127.jpg I think the PAL is just used to slightly alter the timing for PCE. The MK in this case is only used for timing, on the Famicom it's used for composite transcoding as well.
