Steve Anderson wrote:Rapid progress indeed!
Thanks Steve A. As ever it's great to have your interest and support.
Steve Anderson wrote:This is usually some RF/IF related problem (not that the Argus has an IF), either cross-mod from another (unknown) carrier or something isn't quite stable. Or it may be the RF level is a bit high, but if it were OK on 405...
As a start, I suppose I could simply unplug the EF50s on the vision strip one-by-one to trace where this is coming from. The RF input level should be OK. I've already set it to optimal.
Steve Anderson wrote:The flyback problem may be due some time-constant shortfall. First thoughts were C61 (30nF) but as this is rated for 2.5kV it may be difficult to increase the value. Also C40 (10nF) may be worth a look at. If possible have a look at the cathode of V13 and see if there's any tilt in the waveform first.
Thanks - will look into this.
Steve Anderson wrote:It's kinda odd that all of the SP61's in the timebase circuit(s) have zero bias (except V13), but it obviously works!
Yes. Who am I to question this?
Steve Anderson wrote:I was going to suggest providing a baseband input yesterday which if the 'mechanical' standards are not composite a simple mixer to glue on the syncs would be required. This may also help identify if the herringbone pattern is coming from the RF/video section.
Unfortunately a 'mixed syncs' feed does not appear to be available from the WC-01 for the mechanical standards. Instead, you get (in essence) a choice between line and frame square waves. See the Manual ('resources' below). My converter is version 2.1.
Steve Anderson wrote:Seeing you have built this as an almost exact replica of the PT article I understand if you don't wish to add other 'features' to it.
I am relaxed about this. After all, if it had been true to the original article it would never have worked! See
HERE !
My immediate time for playing with this runs out at the end of the week. So thinking about how to get the unit to display 'mechanical' standards could possibly be tackled in a more leisurely way, over the weeks to come?
Resources:
Complete Argus Details
World Converter WC-01Steve O