29 Jan
2013
29 Jan
'13
1:02 p.m.
Are there any recomendations for a converter that can take RGB with
sync on GREEN as input and produce a VGA (or HDMI) output suitable for
driving a modern LCD?
Sivne you mention the VR241 later on, I guess yoy need to do scan rate
conversion too. The VR241 is TV rate (around 15kHz horizontal).
Mos, if not all, LCD TVs sold over here have analogue RGB inputs at TV
rates on the SCART socket(s). It's not sync-on-green, so you may have al
ittle fiddling aobut to do, but at least the inputs exist. I have alos
seen, but have no experience of, a SCART to HDMI interface unit. I assume
tht has analogue RGB inputs on the SCART connector.
I seem to be accumulating numerous older pieces of gear that produce RGB
output and space and reliability of the old tubes to which they connect
is becoming more and more premium. Would like to be able to use an
LCD as an alternative.
A couple DEC VT240 came my way this weekend and they will need some TLC to
restore but the VR240 that came along with them is in even worse shape.
I'll give it my best shot but ability to use an LCD as Plan B would
be nice.
Be warned that the VR241 is not easy to work on. The switch-mode power
supply is mostly on the live side of the isolation barrier and it is
driven by the horixontal oscillaotr (presuambly to prevent paterning from
the SPMSU osicilaltor nd horizotnal oscillator beating against each
other) via a winding o nthe flyback transofrmer which provides isolation
bnetwene mains and output sides. For startup there's a multivibrator
oscilaltor on the PSU board which is disabled when a capacitor shcages up.
Therefore, for the PSU to run, not only doe it have ot be workign
properly, but the horixotnal driver nad output stanges have to be workign
too. Not easy to trace fualts...
IIRC it's actually a Hitachi desing. Certianbly the thick-film module in
the midle of the scna PCB looks like a Hitachi product.
-tony