On Tue, Apr 2, 2024 at 4:40?AM <jking2603@...> wrote:
Is it normal with SGL Trigger A setup as in the photo for the CRT to go
blank?
Yes this is normal.
Why has the CRT gone blank? Is this blank screen what normally happens?
If you read the manual, you'll see that this is normal behavior. For
photographic purposes, the scope will sweep each enabled trace, before
rendering the OSD once, which will give the user a photograph of the whole
mess, assuming the shutter is open for the duration.
This makes me wonder if as you have said the sweep is stuck in Holdoff
or if the Blanker circuit has come on?
IMHO you might want to verify that the holdoff control voltage is correct -
this doesn't come from the A5 board, as I'd remembered, but rather from
U170 on the A1 board. This is another MUX, which has a bunch of S&H op-amps
behind it.
