On 2017-Nov-23, at 5:07 PM, Adrian Graham via cctalk wrote: >> On 23 Nov 2017, at 21:18, Brent Hilpert via cctalk <cctalk@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.
610M ? I hope that M is a typo.
