Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: siastbill1 on July 22, 2007, 12:03:29 am
-
Hi, I recently purchased a working G07. The picture looked ok, but it seemed to have an ever so slight roll to it, in addition to the black background appearing slightly red. I had some time and money to burn, so I decided to do a cap kit and flyback just for preventative measures. I also did the cap "upgrade" to square out the picture and eliminate curl.
The new caps and flyback went in well, and I must say that I noticed significant improvement in picture (partially thanks to the upgrade, which squared the image nicely). The only downside is that I still noticed a slight wave in the picture, as well as the aforementioned reddish tinge.
Here is a flash vid of the wave: http://www.billfriedrich.com/test/wave.swf
To try and troubleshoot, I went through the online G07 walkthrough. It said to check R1, which was hanging off of the chasis. Is this what R1 looks like: http://www.billfriedrich.com/test/r1.jpg
If so, I only received 79 volts from either side, which could mean that cap C904 is bad. Is it also possible that my isolation transformer is not putting through enough voltage under load?
Lastly, when I crank up the power on the flyback, I get horizontal lines across. I assume these result from too much voltage, but here is a pic so someone can help me confirm this: http://www.billfriedrich.com/test/lines.jpg
Thanks for the help!
-
Don't know if you have already, but have you played with your color adjustment pots yet? Contrast and brightness pots? RGB pots on the neckboard (if any)?
Just some things to try.
Also, do you even know what it means to have a "plethora"? ;D
-
Hey, nice "Three Amigos" reference! The first time I ever heard the word plethora was watching that movie as a kid :)
The G07 has adjustments for brightness (screen control), focus, RGB cutoffs (neckboard) and Red and Green drive controls (neckboard). I have tweaked them all, and the pic is ok, although a little red.
My real worry is the waviness of the screen, and in particular, the voltage on R1. Can anyone confirm that what I am measuring is actually R1 (http://www.billfriedrich.com/test/r1.jpg). I am wondering if under powering the monitor might be giving me the waviness (http://www.billfriedrich.com/test/wave.swf)
Thanks.
/bill
-
Still looking for someone to confirm that what I am measuring is R1:
http://www.billfriedrich.com/test/r1.jpg
-
have you reconnected all the grounds,special attention to the neck card to tube ground
-
Yah, all of the grounds are connected perfectly and the overall picture is better than before. I guess I just want to make sure that I am attaining the proper voltage for everything, hence the question about R1. I looked in my manual, but can't seem to find a reference to R1 anywhere. Again, I am only getting about 79 volts DC on the device I have circled in the picture. If this is R1, then I this is definitely too low. If not, then I need to locate R1 and check it.
(http://www.billfriedrich.com/test/r1_big.jpg)
Thanks.
Bill Friedrich
-
You are on the "connection" to the degaussing coil. That's actually AC voltage there. R1 is the large white "sand block" resistor suspended on the side of the chassis. Here is a G07 chassis from Bob's site:
(http://www.therealbobroberts.net/go7-1.jpg)
R1 is the white rectangular "thing" just below the "T" in "The Real Bob" heading.
-
Awesome, thanks tta583. I didn't realize that this image was buried on Bob's site. I will give this a measure and adjust B+ if necessary.
/bill
-
Just to follow up, I measured the R1 voltage for B+, and it was only 110v. I adjusted B+ and I got it to a stable 120v.
This eliminated all of the wavy effects that I was getting in the picture!!!
My only other question is, I touched R1 and it is pretty damn hot. Does it normally run hot, or could something else be wrong? I noticed that the input voltage for R1 is around 160v (again with the output a stead 120v).
thanks