G07 missing top half of picture

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What is all this white gunk on the chassis I circled? It's everywhere in the photos not just where I circled. If it's some kind of corrosion and it traveled up into those pots could be causing your issue.
 
View attachment 853295
What is all this white gunk on the chassis I circled? It's everywhere in the photos not just where I circled. If it's some kind of corrosion and it traveled up into those pots could be causing your issue.


I don't know but you're correct in that it's everywhere. I have other G07s and they don't have this gunk on their PCBs. I'll try contact cleaning and wiping the pots next...
 
To further clarify, this stuff can be sticky and Mattspad's advice to clean the pots is a good idea. Or replace them.

I contact cleaned the pots (v hold, v lin, v height) and wiped them back and forth and re-installed the chassis in the frame.

I'm just using a generic contact cleaner. Everyone talks about deoxit ... is there a difference? Should I switch?

I had my son watch the screen while I wiped the pots and pushed on them and around them. Nothing brought back the top half of the picture. I decided to try the H Freq pot and the picture went dark and there's no more neck glow. It doesn't matter what position I have H freq in now, there's no picture period.
 
I contact cleaned the pots (v hold, v lin, v height) and wiped them back and forth and re-installed the chassis in the frame.

I'm just using a generic contact cleaner. Everyone talks about deoxit ... is there a difference? Should I switch?

I had my son watch the screen while I wiped the pots and pushed on them and around them. Nothing brought back the top half of the picture. I decided to try the H Freq pot and the picture went dark and there's no more neck glow. It doesn't matter what position I have H freq in now, there's no picture period.
Generic contact cleaner is usually what I use 😉 Did you adjust that while the monitor was running with a metal screwdriver? I don't own a g07 but I know on this chassis you need a plastic screwdriver if the monitor is running because the stock pots are unshielded. You may have blown the fuse or hot.
 
I always remove that metal shield thing behind the H. Hold (H. Freq?) pot. I used a little metal precision flathead there once and made it mad briefly. lol
 
Generic contact cleaner is usually what I use 😉 Did you adjust that while the monitor was running with a metal screwdriver? I don't own a g07 but I know on this chassis you need a plastic screwdriver if the monitor is running because the stock pots are unshielded. You may have blown the fuse or hot.

Drats. That's exactly what I did. :(

The fuse is positive for continuity so I'll see if I fried the HOT next...
 
I've done that and a power down and power up brought the game back up. Other times I think I fried one of the fuses (not certain about that though).

I ALWAYS, 100% of the time replace the pots with newer ones , which also happen to be plastic, so no shorting things out. And...I get rid of that stupid metal shield.

nobody else has to do this, it's what I do. :)
 
I've done that and a power down and power up brought the game back up. Other times I think I fried one of the fuses (not certain about that though).

I ALWAYS, 100% of the time replace the pots with newer ones , which also happen to be plastic, so no shorting things out. And...I get rid of that stupid metal shield.

nobody else has to do this, it's what I do. :)

I can replace the POTs. The RF shield is just ... stupid?
 
If you B+ is too high, is the pot not adjusting it down?

HIGH HORSE EVERYONE:

It's a waste of everyone's TIME, to troubleshoot something that hasn't been rebuilt. Pots, caps, etc. I don't care what anyone else's opinion is on this topic.
( this isn't directed at you by the way :) ).
So , change the B+ pot , if it has already been changed, it isn't the issue. After that we can efficiently diagnose moving forward.
 
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If you B+ is too high, is the pot not adjusting it down?

HIGH HORSE EVERYONE:

It's a waste of everyone's TIME, to troubleshoot something that hasn't been rebuilt. Pots, caps, etc. I don't care what anyone else's opinion is on this topic.
( this isn't directed at you by the way :) ).
So , change the B+ pot , if it has already been changed, it isn't the issue. After that we can efficiently diagnose moving forward.

I do not know if Buffet replaced the B+ pot or not but I was able to adjust it to 120V. Do you still want me to replace it?

I had left the power off for a few days and when switched on today there is now an image back on the screen. Because I fiddled with the pots it's not where it needs to be in terms of adjustment but the vertical collapse is still present.
 
I do not know if Buffet replaced the B+ pot or not but I was able to adjust it to 120V. Do you still want me to replace it?

I had left the power off for a few days and when switched on today there is now an image back on the screen. Because I fiddled with the pots it's not where it needs to be in terms of adjustment but the vertical collapse is still present.
It keeps sounding like you need replace all the pots
 
I had a chassis that x401 and x402 measured good in and out of circuit. After changing both transistors, I got full deflection.

I've also noticed c402 is a cap that has been bad in a few chassis.

Ic501 is last resort when everything else checks out. I've only come across one chassis that had a bad one.

@tron guy gives a pretty good list of things to always check. I usually just look up one of his for sale threads for the cheat sheet and "copy his answers." LOL
 
Thanks. I replaced all the pots on the PCB including the B+ ... unfortunately still experiencing vertical collapse.
Even though it didn't fix it, it's good you changed those anyways and it eliminates a variable. Paging @tron guy he'll know what to test next, although chilibear likely helped narrow it down for you. I'm not familiar with these chassis myself like I stated before, but what chilibear is saying sounds right.
 
Did it take 10 years to get it back from him?

Are you able to work on these yourself at this point? There are many things that would/could cause this issue.

FR401
X401
X402
C402
10k pot
both 200 ohm pots
D101
D102
D103
IC501

and on, and on

bad traces (though since it was working, I would consider this last)
tron guy made a list already.

I've spent 20 hours tracking down V collapse before (unfortunately). At this point, I would be pushing on the chassis all over the place with something plastic and being very careful not to get shocked, OR, to push the chassis so hard it shorts out to the bottom metal chassis frame. Looking for a jumpiness or change to the v-collapse. Odds are, you have a cracked/bad trace.

Start beeping out the entre center of the chassis. It's NEVER 1 crack (for me at least), I always get excited when I find a bad trace, I run a jumper, no fix. lol , it's funny now that I'm not living it.
 
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