[time-nuts] ANFSCD - Synchronizing time in home video recorders

Hal Murray hmurray at megapathdsl.net
Thu Feb 2 06:49:36 UTC 2012

> Failing that, can the crystal that determines time for the DVR be adjusted?

What sort of crystals do you find inside?  My guess is there are two of them, 
one at 32KHz used for timekeeping, and one at ?? MHz for the CPU.

I think I've seen comments about making 32 KHz from 10 MHz in a PIC or AVR.

tvb has this web page, but I don't see a 32 KHz option:

Anyway, the idea would be to find the 32 KHz crystal inside your DVR and 
replace it with 32 KHz derived from your TBolt.  Most of the clock chips have 
an internal amplifier connected across 2 pins, often labeled something like 
X-out and X-in.  The idea is to put a signal on X-in and ignore X-out.

I'd probably take a look with a scope, and then see if I can make something 
with a few resistors to get the right level and a 1-meg to connect that 
signal to X-in.

These are my opinions, not necessarily my employer's.  I hate spam.

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