CurtPalme.com Home Theater Forum

geofbuck · Joined: 16 Jun 2009 Posts: 13 Location: Toronto, ON Canada

Does anybody know where the G4 VOL electronic focus adjustment knob is. I have purchased 2 D50's and am setting 1 up with the service manual, but I can't find any reference as to where this knob is on the projector. I must be missing something... Help anyone! Thanks.

**AnalogRocks** · Posted: Wed Jun 17, 2009 4:13 am Post subject:

I've set up a D50 several times and never had to play with that. What page of the manual is it on?

geofbuck · Joined: 16 Jun 2009 Posts: 13 Location: Toronto, ON Canada

Its in Section 3 ADJUSTMENTS first refenced in 1-3-6. 2/4 pole Mg adjustment. I went through the standard calibration procedure from pages 63 to 114, but I am having a few problems. First, I can't seem to get proper grayscale adjustment at low IRE. I can dial in the gain but any adjustment in bias has little effect. Blue is off the chart and picture looks green at low IRE. And strangely, adjusting brightness has no effect at all from 0-max in user controls. ABG is ON. Also, any portion of the picture with bright white such as white type on a black background has a smearing or tracer effect that goes off horizontally to the right. I can't seem to get rid of it. I am using a Sencore 403 and an OTC1000 to calibrate the D50. Any help is appreciated.

**AnalogRocks** · Posted: Wed Jun 17, 2009 2:30 pm Post subject:

The D50 is known for the streaking you are seeing.
What does the blue tube look like? Is it burnt looking if you look into the lens?
You may have a board failure. What happens if you ramp the contrast/brightness all the way up and down? Do they change allot or hardly at all?

geofbuck · Joined: 16 Jun 2009 Posts: 13 Location: Toronto, ON Canada

If I ramp the contrast up/down it does work but not the brightness. 0-max has no effect. I tried looking into the blue tube and it looked fine. The reason I was wondering about the G4 VOL electrical focus adjustment is for doing the blue defocus. Thought I could tighten it up a bit.

**AnalogRocks** · Posted: Wed Jun 17, 2009 3:34 pm Post subject:

First things first. You have a bad board in there. Curt can send you another one. I'll ask him to pop in here and have a look. He'll know off the top of his head which board it is. I had the same problem on mine.

**Curt Palme** · Posted: Wed Jun 17, 2009 3:40 pm Post subject:

Either your PA board is bad (HV regulator located under the green tube), or your CRT socket(s) are bad.

One simple test is to turn off each tube on the back of the set via the buttons. If the tubes flash when you turn one tube on and off, there are some parts that have failed on each CRT socket, you may as well get all three repaired at the same time. If there's no quick flash as you turn them on or off, then it's the PA board. Shoot me an email to curtpalme@shaw.ca to discuss costs and turnaround time.

I'll answer tomorrow, I'm in Seattle today.

Cheers!
Curt

geofbuck · Joined: 16 Jun 2009 Posts: 13 Location: Toronto, ON Canada

Thanks for the info! I will check the tubes tonight after work. I actually have 2 D50's. Got them both a couple of weeks ago from a repair shop for $150. I was keeping one for parts as it has a bad input card. Any idea where that G4 VOL adjustment knob for electronic focus is?