25 Nov
2017
25 Nov
'17
8:05 a.m.
On 24 Nov 2017, at 08:44, Adrian Graham via cctalk
<cctalk at classiccmp.org> wrote:
Gah, ignore this.
?
Adrian/Witchy
Binary Dinosaurs - Celebrating Computing History from 1972 onwards
On 24 Nov 2017, at 08:41, Brent Hilpert via
cctalk <cctalk at classiccmp.org> wrote:
On 2017-Nov-23, at 5:07 PM, Adrian Graham via cctalk wrote:
610M ?
I hope that M is a typo.
Morning!
It is, 610k or 0.6M :)
On 23 Nov
2017, at 21:18, Brent Hilpert via cctalk <cctalk at classiccmp.org> wrote:
...
You might check the contrast control.
I can't find the actual schematic for the contrast control connections, but I 'm
guessing the ends are connected across 12V (video board pins 5 & 1/4/10) and the wiper
to video board pin 8.
The contrast control can be expected to take pin 8 somewhere + to get pixels fully on.
You?re right with pin 8, tracing the circuit I can see why someone recommended I check
Q101 and Q102 which look OK in my tester.
The contrast control itself tests OK resistance wise, it goes from pretty much 0ohms to
610M.