Main > Monitor/Video Forum
Electrohome G07 CB0 is dark
Ken Layton:
Vertical collapse is usually caused by that 68 ohm 2 watt resistor going open circuit.
Here is where to buy it:
https://www.arcadepartsandrepair.com/store/components/resistors/68-ohm-2-watt-wirewound-fusible-resistor-3-pieces/
https://www.twistywristarcade.com/monitor-components/747-68-2-watt-fusible-resistor.html
ncflagg:
I pulled FR401 and it still tests at 68ohm. I went ahead and built a 70ohm 2W resistor (just for testing, I know it needs flameproof resistor permanently) and the vertical collapse continues.
ncflagg:
Inspecting more, R526 (1K 1/4W) is what burned. Trying to replace that one..
Edit: No change. Still have vertical collapse.
Ken Layton:
Maybe the two vertical output transistors have gone bad?
If that little tantalum capacitor next to the IC (underneath the metal shield) goes bad, you'll get vertical collapse. It's typically NOT included in some capkits.
ncflagg:
-sigh- Vertical collapse was another symptom of my apparent dyslexia. I had my custom 180k resistor in the R522 position. Once I put my custom resistor 180K 3/4W in R517 and put the old R522 back in place, the vertical collapse is now fixed.
I'm now back to the dark picture issue; went through all the monitor controls again. I'm also noticing that the picture pulses occasionally. About every 5 seconds or so (not super regular), the picture shrinks by a few percent and then immediately goes back to the usual size.
I'm going to explore another possibility, that there is no problem. My VGA cable is connected directly to the input of the monitor which definitely used to work. The video card which used to work was killed when that PC died. I'm starting to wonder if that video card just happened to put out more voltage, and all the replacements I've tried do not (1v vs 4v, perhaps). I'm ordering a VGA amp and will test that.