I am looking at overclocking a Dreamcast VMU HKT-4100 and struggling to locate a suitable alternative ceramic resonator to the 6.00MHz already inside it. I am preferably after something in the 8.00MHz range which should cover the Dreamcast being overclocked to around 260MHz. The type in the HKT-4100 looks to be an SMD made by Matsushita which, is now part of Panasonic. I am guessing from it's dimensions the part number in the attached photo may be either an EFOS or EFOSM with built in capacitor as it looks very similar in scale to that in a datasheet I found. Is anyone able to confirm or deny if this is true and where I may be able to purchase these from please? I have come across a seller on eBay - though the postage fee they are asking for is laughable... Ted.
I should add that last resort will be to use a HC-49 quartz crystal with two ceramic disk capacitors... Ted.
I have personally used a standard 2 pin 9mhz Xtal to replace the ceramic 3 pin SMD ones in the newer VMU's and have had zero issues. I leave the middle pad disconnected, I've heard there should be a resistor between the middle and outside pads but have seen no need to do it. Also see my post here regarding overclocking the VMU: http://assemblergames.com/l/threads/clearing-up-vmu-overclock-misconceptions.61174/
Yes, that is what I'd be doing with the HC-49 crystal though I'd rather use a couple of capacitors too than chance damaging the VMU. How far have you pushed your overclock? I already have a Dreamcast running at 240MHz without any problems at all. I am modding another one with a selector switch to turn the overclock on/off and using a chip holder for the oscillator so I can swap out different range of crystals if required. I've seen Dreamcast's pushed to 260MHz though not sure how stable they run... Ted.
I've only pushed to 240mhz with a switch to change between OC and Stock. I saw no point pushing further as most homebrew and official games see a considerable speed boost at only 20%. Unfortunately the latest firmware update for USB-GDROM has broken OC compatibility in official games.