G07-fb0 minor problems

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Have a 13inch G07-fb0 which came from a midway cab/pacman.
--Using the original isolation transformer.
--Was rescued from a water damaged cab in a damp basement, but monitor chassis not corroded/rusted
--I'm not monitor savvy, but can handle basic schematic work and have replaced a handful of capkits in other chassis. very novice, here. Thank you in advance.
--Did the cap kit from bob roberts.
--Did NOT replace the large ?filter? cap.
--chassis is grounded to the GND on the switching powersupply.

Problem 1-
There is a slight sine wave in the screen on the right.
--I can almost get it to go away with fine/finger push adjustment of the H.Freq pot.
but then the wave will just flip the other way.
--The H. Freq pot adjustment is very unforgiving and it's easy to cause the screen to go into striated diagonal lines.

What is causing this?
--Is this 60hz? will replacing the big cap help?

Problem 2-
the right side of the screen is slightly wider than the left side.
--notice the bricks i highlighted to emphasize the issue.
--play is decent but scrolling left or right creates an "accordian" effect as the bricks expand or contract in width.

Problem 3-
When I was running a Rockola Nibbler PCB, I was able to use the horiz and vert size to get the playfield to fit the monitor screen
--now that I'm running Tut, I can't get the horiz height to fill the screen. the horiz coil is adjusted all the way out, but it only made about 1/4 inch adjustment anyway.
--the vertical is pulled in to make the display items seem proportional. adjusting the vert any wider and it starts tearing the vertical lines into bars with spaces.


tutscreen.jpg
 
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Did you replace the fly? I had the exact same issue when I replaced the fly. The G07 FBO uses a different fly than the CBO - and they ARE NOT available...

Same wave in the lower right corner when I put a CBO fly in. And same issue with the picture not filling the screen.

As for the POT, I would reflow and then cycle several times. If it was in a water damaged cab, it might have rusted inside. You can also replace it should you choose.
 
I didn't replace the fly. just the basic cap kit and reflowed connections.

but i suppose it could still be the wrong one in there from days gone by.

I'll open it up this week and measure the voltage for B+ and double check grounds.
 
I'll open it up this week and measure the voltage for B+

Just to bring this to attention, for anyone that may see this thread in the future, this is one of those things that should /always/ be checked.

We should have a list of monitors and their respective B+ test points.
 
Black lead on the frame, red lead on the white wirewound resistor, tab closest to the tube. The resistor that's mounted to the frame.
 
That's not even remotely correct. It should be ~120VDC.

Check your solder joints. Last one of these I worked on that was the issue. Hit all 500 and 900 series parts.
 
sorry. i had the meter on AC.

It is actual 120.3 V dc.

When I did the cap kit I did hit all solder parts that looked even slightly questionable.
 
R314 has infinite resistance.
the others are 392-396.

sounds like a start!
 
no. the schematic shows one lead goes to ground.
do i need to?
 
Meh...I'd just replace it and be done with it, if there was a question.

I'm going to buy some soon, and put them in the store, but I haven't yet.

If you have to wait, just lift a leg and meter it to be sure.

Also, are they all the same (390 Ohms)?
 
close 392-396.

you gave me a good start, i pulled the chassis and will check around at all the transistor circuits.
if one is bad then it probably came from a similar aged batch......
i'll probably test a lot of the parts now just for the exercise of messing with monitors.

thank you. i'll update when i have resistors installed.
 
ended up putting this monitor project on the backburner.
going with an LCD in the cab for now.
thank you for the direction, it'll save this monitor when I get back to the project. :)
 
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