Hi,
I'm interested in seen those photos, because I collected a bunch of then
from various owners but I dont see this 'AC161 even on in the switching
regulator pair.
I made a goof the other day when I connected the 5 V input to a 15 V
power supply and toasted the 'ACT240 buffer which drives the lock
indicator and the PPS outputs. I know that the 5 V is used to generate
the +3.3 V in an internal regulator and because I'm not sure what else
is toasted I want to trace this voltage and see if it is ok. The unit
is mostly working, it locks and also generates the 1PPS, measured at the
input pin of the buffer, but I want to check everything that can be
damaged and replace the failed parts.
So I'll benefit from partial schematics, parts location and
identifications and all the like. Please share the info that you have.
Best regards,
Ignacio, EB4APL
On 11/01/2012 19:22, Peter Bell wrote:
You can put me in the "No 1 PPS on pin 6" camp, too - I made extensive
attempts to detect it on the first couple of units (multiple scopes,
even connecting in to an edge-sensitive interrupt pin) and detected
nothing. The other units, I just poked a scope (TDS420A) at it, but
could see nothing.
One thing I did notice was that in one of the photos on here (the one
about the 5V switching regulator) there were some components ('AC161
and associated parts) installed on the PCB that were not present on
any of the units I opened. This may be related, or may not - but at
the least it does suggest that despite having the same P/N these units
might not all have the same build spec.
Regards,
Pete Bell
On Thu, Jan 12, 2012 at 12:54 AM, beale<[email protected]> wrote:
All three of my FE-5680A units show a constant DC voltage on pin 6, with
absolutely no PPS signal. This is when pin 3 is low (lock) and the 10 MHz
output is indeed locked at 10 MHz (within 4E-10 anyway). I am using a Tek
TDS-210 digital scope which certainly has no problem with a 1 usec pulse, and
in fact, I did see a nice square 1 usec pulse on Pin 6 once, from one unit. But
it went away after a power cycle, and did not return. I know many (most?)
people do see the 1 PPS so perhaps all three of my units are damaged (?)
I presume the 1 PPS signal would come from the XC9572 CPLD which also drives
the 10 MHz signal, so I'll try tracing back which pin that is. I labelled a
few CPLD pins already (60 MHz in, 30 MHz and 10 MHz out) here:
https://picasaweb.google.com/lh/photo/dUtTwuNnP-y2nL-wR84ELNMTjNZETYmyPJy0liipFm0
-------Original Message-------
From: Chris Albertson<[email protected]>
To: Discussion of precise time and frequency measurement<[email protected]>
Subject: Re: [time-nuts] FE-5680A arrived
Sent: 11 Jan '12 08:37
On Tue, Jan 10, 2012 at 10:11 PM, Joseph Gray<[email protected]> wrote:
> I'm not seeing a PPS on either of these. All I see is about 17 mV P-P
> of noise that looks like a multi-stepped sine wave. I'm using a TDS
> 340 scope.
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