You can find these oscillators on aliexpress. they're much bigger though, but you can glue the oscillator to the rf shield and route the wires through to where you hook up the signal. Here's an example of how I do oscillator mods on PS1s:
https://retrofreedom.com/ps1dfo.html
NOTE: It's not exactly 53.69mhz. it's actually 53.693175 mhz.
That's what you should search for. AliExpress is basically china's official website
NOTE: Those bigger oscillators are normally used on 5v systems but they usually work on 3.3v power rails. PS1 uses 3.3v everywhere, including for oscillator.
EDIT:
Also, beware the difference between a crystal and an oscillator. What you want is an oscillator.
If you see 2-pin oscillators, they're not oscillators, those are just crystals. The oscillator is the circuit that generates the sine wave, in this case it's a "crystal oscillator" circuit.
Actual oscillators have 4 pins, not 2.
I recommend using real oscillators, not clock generator / synthesizer like the other person above recommended. Real oscillators tend to produce much cleaner waves (as seen on oscilliscope)