[time-nuts] Sayrosa 607B Frequency Synthesizer
GandalfG8 at aol.com
GandalfG8 at aol.com
Sun Nov 25 15:31:48 UTC 2012
Hi Mike
I haven't seen too many of these in the wild so can I assume this was the
unit recently sold on Ebay?
If so you got an excellent drive unit at a very good price, even if it
isn't working at the moment:-)
FCO standard equipment with these was the HCD-1519 1MHz frequency
reference and whilst they are specified to run from 1, 5, or 10MHz I've not run
them from anything else so not sure offhand whether these frequencies are
automatically accepted, which I suspect they were, or whether internal
selection is required but I should be able to check on that.
As you suggest, the output is inhibited whilst the fault indicator is
illuminated.
Is there a number showing on the display to go with your "Fault"
indication, and are any other of the indicators illuminated?
It's possible a link may be required on one of the rear connectors to
enable stand alone operation but again I can't remember offhand so will check
and come back to you on that too, but there shouldn't be any significant
wiring needed.
Like much equipment from that era though these units suffered the dreaded
tantalum capacitor disease and it's quite possible that one or more modules
may be afflicted.
First thing to check is the power supply.
There are 5 separate supply rails with two each of plus and minus 12 Volts
and one of plus 5 Volts, each using an appropriate 78xx or 79xx regulator.
If any are at zero this obviously indicates a possible failure but also
perhaps a shorted supply line so this needs to be checked.
Whatever the results here you though you should still check each of the
internal modules.
Where the supply rails attach to the circuit boards in the modules the
first component in most, if not all cases, is a small series inductor which is
followed by a 10uF tantalum capacitor to ground. If this or another
capacitor has failed short circuit, which is the common failure mode, it could
either be pulling the rail down or it's possible that the inductor will have
burnt out which will restore the external supply but leaving part at least
of the module non functional.
If this does turn out to be the case and proper replacements aren't to hand
a short term fix, although not recommended in the longer term, is to use
standard electrolytics for the caps and wire links to replace the inductors.
Good luck:-)
Regards
Nigel
GM8PZR
In a message dated 25/11/2012 09:39:11 GMT Standard Time,
mike.millen.uk at gmail.com writes:
This unit is a part of the UK's Diplomatic Wireless Service's "Piccolo" HF
RTTY network.
I have acquired one of these & am trying to get it working.
It accepts a 10MHz (or 1 or 5) reference & the output can be set to any
frequency between 3MHz & 29,999,900Hz, in 100Hz steps.
My unit is showing a "Fault" LED on the display, which I believe is
inhibiting the output. I can see a varying frequency at the o/p socket, but only
a few mV, not the 1v into 50R as is normal.
I suspect that the fault indication is because there's nothing plugged
into either the "Keying Frequency Control Input" nor the "Carrier Frequency
Control Input" sockets. (There's also a "V.F. Inputs" & "Carrier Output
(BCD)" sockets.)
Can anyone help with a manual or connection details for the 2 input
sockets, please?
Many thanks,
Mike
M0MLM
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