16 Jul
2011
16 Jul
'11
12:59 p.m.
On 2011 Jul 14, at 6:19 PM, Vincent Slyngstad wrote:
> From: "Brent Hilpert": Thursday, July 14, 2011 5:20 PM
>> When powered on the PWR-OK & CPU-OK LEDs light up and the CRT
>> filament lights up, but there is no sign of any raster. Kind of
>> looks more like the monitor is dead (no trace of beam when powered
>> down for example). I take it (due to absence of physical controls)
>> brightness and contrast are software controlled (I didn't remember
>> VT100 class stuff being like that). Anybody happen to know whether a
>> bare Decmate like this (no keyboard, no disk drives) should display
>> anything on-screen upon power-up?
>
> I'd have to look into that. The DM II and DM III display an error
> code on the screen, but I don't know offhand about the older VT-278.
For the record, checked it out with the scope, no activity on the sync
or video lines going to the monitor board, and no sync signals coming
out of the 5027 CRT controller. While it could be a hardware problem on
the processor board, it looks likely the boot process is hanging up
before it gets to initialising the CRT controller.