G07 B+ Question

bluestreak

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Attached is a pic of the issue I'm having after a Cap, Flyback, and HOT replacement with the screen skewed on the right side.
I am trying to measure the B+ but not sure if I'm measuring at the right place. I'm using Bob Roberts diagram and measuring off of the large white resistor mounted on the side and am getting 109VDC and the B+ pot will not make a difference on the reading when adjusting it.
Am I measuring at the right point and could the B+ be causing my issue?
 

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it looks like you have the synk hooked up wrong.
or its a horizontal position adjustment is needed.

109v is low it should be 120v.
i forget off the top of my head what point to measure the B+ on a G07 but others will chime in on where it is.

Peace
Buffett
 
it looks like you have the synk hooked up wrong.
or its a horizontal position adjustment is needed.

109v is low it should be 120v.
i forget off the top of my head what point to measure the B+ on a G07 but others will chime in on where it is.

Peace
Buffett

Measure the B+ on the pin that is closest to the tube. Not able to adjust it could be a bad regulator, but would probably be a lot higher than that, but not necessarily.
 
Slackmoe, I've tried the horz adj prior and it never would take out the curl and now it's become way worse so I feel there is a failing component somewhere.

Peale, not sure what you are asking referring to a multi-board.

Docfrankie, thanks for the links, I'll check them out also.
 
Is this a multi-board?

I think what he is getting at is some G07's don't respond well to multi-boards ie. 60 in 1. I have a G07 that has a bit of curl with my 60 in 1, but when I hook it up to my Pacman, it looks great. If you are trying this with a multi, do you have another working jamma PCB to try it with?
 
This is on a dedicated Arkanoid boardset. Will try to obtain the regulator and X901,X902 today to see if those are the issue, at least in the B+ area.
 
Have exact same issue after recap at 109VDC. Manual is lacking on parts list but was able to gleem from another uninstalled board but no markings on X04 transistor (probably the issue). Any reference to these?. Under cell magnification X901 is a NEC C2689 and X902 a C1590. Would love an answer before ordering.
 
Check R908 (47K ohms), B+ pot and X901. Thse are the 3 parts that I see bad (in no particular order or all at the same time) when the B+ is low and won't go above 109 volts.

If X04 was bad your B+ would be around 160 volts and you would be in HV shutdown.
 
B+ now adjusted after replacing the two transistors X901 & X902, but still get the same blue grey screen before cap kit, and using a TPG2. Replicated two different connections from web and a jumper connection from Mike's Amatur Arcade Monitor YouTube GO7 video, so progress is still not a working monitor, any suggestions?
 
Ok now I have 2 bad GO7. Other blew F901, when powered. Compared inline and both G07 and both R516,517 read 22.5 kohms will follow up on desoldered reading.

Noticed with TPG that the blue screen actually has an image washed out. At first I noticed switching modes that the animation of the curve, and some grids I could see the separation bands. Sorry about the oblique angle but only way without the video screen moire pattern
 

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sounds to me you have a issue in the video processing section.
i see this on many different chassis.

check for any solder bridges, this is the most common issue.

if you need it repaired, your welcome to send it in.

Peace
Buffett
 
Thanks will be checking again..Attempted to do the GO7 white adjustment from the manual and discovered the red pot on neck board moves with no effect, likely toast, and that the contrast adjustment on flyback will not go low enough to lessen the brightness, However, I do get a transition from scanlines to even bright blue green bright gray now. Following the Flowchart for now, but thanks for the offer.

On the second GO7 from a necked tube, which I rebuilt broken neck board and resister, after I recapped it, replaced the fuse....To my surprise It did not blow...but now discovered a busted rusted out B+ POT, and a voltage of approx. 155V. Is this to be expected of just a failed B+ POT?
 
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