WTB: xtal@21.47727 (for NTSC)

Hi Everyone,

I'm interested in getting some xtal components at 21.47727 for an NTSC famiclone mod. Anyone know where to get these without butchering up NTSC Famiclones to get them? :thumbsup:

 

Haha. Let me know if you have any luck. I posted this just 2 days ago for a SNES 60Hz mod on a newer board.
I would be interested in a few myself.

 

http://parts.digikey.com/1/parts/396002-crystal-21-47727-mhz-ser-49us-ecs-214-7-s-4.html

 

Found those but shipping is like $40USD
Might as well buy a famiclone form volumerates and get one landed cheaper.

 

Digikey do free shipping if you order a certain amount (£50 or so).

Buy everything you need in 1 go and get free shipping.

Failing that, I can add some to my next order and forward them on

 

Crystals can't be dropped into place of another without knowing 1) the circuit's load capacitor orientation and value and 2) the required tolerance.

That D-K crystal is a series load (FC clones probably use parallel in order to use a cheaper Pierce oscillator, original FC have options for either to be fitted in the factory) and it specifies a 30 ppm tolerance. NTSC colorburst is supposed to be within 3 ppm. For 3.58 MHz that means it can have an error of less than 12 Hz! In practice TVs will tolerate a bit more, but with 30 ppm @ 21 MHz the error can be over 630 Hz, which divided by 6 to get "3.58" can be over 105 Hz, not good.

In all the oscillator will oscillate, but 1) the tolerance is bad so the frequency will be off and 2) using a series Xtal with a parallel config will make it further off and 3) using the wrong capacitive load value will make it even further off. Frequency off = colors off and changing, audio pitch shifted (very slightly since it's divided down much further for audio range).

Something I've wanted to do is order a batch of them from FOX, but I have no money for it now.

http://www.foxonline.com/

 

I had figured that (after my crash course a few weeks ago working with the CXA1645) but a single part is better than trashing a whole console for the same part IMO. Even if it means being off by what (hopefully but doesn't look likely) would be less than noticeable.

Plus it was the cheapest crystal I saw at that price. I find people don't give a damn about matching parts if there is something cheaper available.