G07 CB0 Help

ArcadeGreg

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Hey guys,
I need some help with the G07. I have a Playchoice 10 with a in-game width issue. I have made a video (link below), which details the unit. The video is almost 8 minutes long. It did't feel like that long when I was filming. If you want to skip ahead to the 7 minute mark thats where I show the problem I am having. Any suggentions would be great.
Thanks All!
Arcade Greg

http://www.youtube.com/watch?v=XcVxHBL6_UY
 
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there should be a control to fix that but i cant remember off the top of my head where its at, also if you havent already you should do a full cap kit with a new flyback that may even fix it
 
The chassis has been fully re-worked. New cap kit and flyback.
 
So, what, the screen is too wide and gets cut off on the left and right? First, be sure your B+ is adjusted properly - it should be 120vDC. If it's too high, then the picture will be too large to fit on the screen. If that's OK, then you can make the picture narrower by adjusting the horizontal width coil - it's the white plastic coil sticking up from the chassis. Adjust this ONLY with a PLASTIC hex adjustment tool - a metal one will break the core.

-Ian
 
In addition, I measured the B+ voltage at the end of the large white ceramic thing on the chassis and it reads 118.6VDC. I keep reading that it needs to be exactly 120VDC. Also, there is a white putty substance covering the B+ votlage adjustment nob. SHould I remove the putty and adjust the B+ voltage, or is 118.6VDC close enough?
Thanks,
Arcade Greg
 
118.6 is fine. Doesn't have to be 100% exact, and it's much better that it be a bit low than too high. And that volt and a half that you're low isn't going to change anything. The white putty is a factory thing, they set up the B+ and glued the pot there so it wouldn't get twiddled by people that didn't know what they were doing :) Generally, you only want to adjust the voltage if you need to - because there is a chance that the 30 year old pot is going to be flakey if you move it for the first time since 1981.

-Ian
 
Ian,
I have tried to stick my plastic monitor tool into the width coil and I have turned it, but nothing happens. Although, I think I wasn't pushing the tool in deep enough or something. I will try it again and let you know what happens.
Thanks,
Arcade Greg
 
Can you feel the slug turning in the sleeve? The width coil is a very common failure on the G07 - it gets brittle with age, and the slug gets frozen into place and won't move. Also, it's pretty common to find the plastic broken apart.

-Ian
 
Ian,
I looked in the bottom of the width coil and there is nothing there. No slug, screw, nothing except the base of the PCB Also, there is no spot for a slug or screw at the bottom. I looked at my old G07 CBO chassis (the width coil on that board is broken), and there is nothing at the bottom of that one either. Am I supposed to be turning the white tube at the top of the coil? Any suggestions?
Thanks,
Greg
 
The inside of that white plastic tube is threaded. The slug is a little ferrite thing that's threaded on the outside and screws down into the plastic tube. On the outside of the plastic tube is the coil itself - the windings of copper wire. What you're doing when you adjust it is you are moving that ferrite slug up and down inside the plastic tube - and moving it in and out of the center of the coil. The plastic tube does not turn. Neither does the coil. The little gray ferrite slug turns inside it. It has a hex shaped hole in the center of it, that you use to turn it with - by way of your plastic hex shaped adjustment tool. You should be able to look straight down into the top of the plastic tube and see the slug - it's a little blackish gray thing.

-Ian
 
Ian,
I just watched a video of a guy adjusting his width coil and I was able to see the screw. I have come to the conclusion that my width coil is missing the set screw. Can I replace this screw? Is it a special screw that I need to order?
Thanks for all the help,
Greg
 
Yeah, it's a special piece of material. It's not just a screw - it's a specially made ferrous material. Unless you have another similar width coil to steal a slug from, just replace the whole coil - it's a pretty common failure anyway(mostly because the plastic gets brittle and breaks), and new ones are readily available from Bob Roberts for $10.

-Ian
 
If the width coil is brand new, let the monitor run for a good couple hours before you attempt to adjust the width coil. The new width coil sleeves are very tight and if you try to move the ferrite core too soon, you're gonna break it.
 
Thanks for the post Dokert. Very useful vid! Now all i need is one of those insert screws...I guess I will take RetroHackers (Ian's) advice and order an new one from TRBR. Again, thanks for all the help guys!
Arcade Greg
 
I'll add a bit more advice since Dave was nice enough to spread the love with a video:

I have had many of these new width coils that won't budge right out of the package. Heat it up a bit with a hair dryer and then thread out the ferrite shaft. Lay on the anti-seize, and thread it back in, if it starts to bind at all, heat it up again and run the shaft up and down several times. This should stretch the plastic sleeve out just enough so you never have an issue with it again.

Nice video Dave, you have such pretty hands and an eloquent way of speaking.
 
I had previously looked that page on TRBR, but I failed to really read it until you (modessitt) brought it to my attention. Good find! I have an old chassis that needs those width caps, so I will pay close attention when recaping it. I am new to this community, but I have found it to be filled with the nicest, most dedicated, genuine people. Again, thanks for all the help everyone.
Arcade Greg
 
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