> Having recently changed the backup battery and several capacitors I find that > now the display "flickers"; i.e. it varies intensity while in operation > despite the adjustment of the VR remaining constant. I don't have much > experience but I believe it was stable before commencing work. > > Just now I was working in the BASIC editor and after a few minutes noticed > the display occasionally making subtle variations in intensity. As time went > on the variations became more frequent and the swings in intensity wider. > > Finally the display went blank, and now when I turn the unit on I cannot > adjust the VR to get any display at all. This happens under alkaline power > or from the 6 VDC adapter. Something is failing but I don't know what: The > variable resistor? Capacitor? Bad connection at the motherboard? > > Can someone suggest a likely place to start? > > Thanks, > > -CH-
Does the contrast adjustment work to adjust the intensity of all pixels even when the display is "dead"? Is BASIC still functional when the screen is dead? (The "cold-start, <Enter>, BEEP<enter>" test). I've seen / heard of the contrast pot failing, and you can test that in-situ pretty easily to make sure the adjustment is smooth. -Josh
