[time-nuts] Raspberry Pi 4 oscillator replacement

[Avamander]

> 2) Grab any of the various conversion chips to take the 10 MHz to 54
(= I don’t know of a standard that puts out 54 MHz). Wire the 10 into it
and pull the 54 off of it. (Yes, the chip needs to be programmed and
there will be various bits and pieces connected to it)

Do you have any recommendations as to which chip would let me achieve this?

In any case, thanks for the help. I will try and document the process when
I start it and share it here, might be interesting for some.

On Thu, Feb 4, 2021 at 5:15 PM Bob kb8tq <kb8tq at n1k.org> wrote:

> Hi
>
> Pretty basic approach:
>
> 1) Get a Rb standard.
>
> 2) Grab any of the various conversion chips to take the 10 MHz to 54
> (= I don’t know of a standard that puts out 54 MHz). Wire the 10 into it
> and pull the 54 off of it. (Yes, the chip needs to be programmed and
> there will be various bits and pieces connected to it)
>
> 3) Rip the oscillator (or crystal) off the RPi board.
>
> 4) Figure out which pin is the drive to the crystal and which is the
> return.
> (or which is the output if it’s an oscillator)
>
> 5) Wire the 54 MHz into the return / osc out pin.
>
> 6) Power it all up off of a common supply ( = power the conversion
> chip off the RPi’s regulator.
>
> Yes there is a lot of research needed to complete all of that.
>
> When done you would need to figure out how to ( … if you can ) disable
> the spread spectrum stuff on the clock. You still would be stuck with
> the normal issues related to clock frequency stepping ( turbo mode …).
> How much of that actually gets you on an RPi 4 … who knows.
>
> Bob
>
> > On Feb 4, 2021, at 5:20 AM, Avamander <avamander at gmail.com> wrote:
> >
> > Hi,
> >
> > I was wondering if anyone here has replaced the 54 MHz oscillator on the
> > Raspberry Pi 4 with a GNSS-disciplined rubidium standard? An overkill
> > upgrade, but is technically doable? What hardware would it take in
> addition
> > to a GNSS-disciplined rubidium standard and a Pi 4?
> >
> > Here's where I got my inspiration from, someone replacing the oscillator
> on
> > a Pi 3 with a TXCO:
> >
> https://raspberrypi.stackexchange.com/questions/74482/switch-out-the-x1-oscillator-on-a-rpi-2-3
> >
> >
> > Yours sincerely,
> > Avamander
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