G07 CBO 19 wave (again)

ivanx

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Hey all, I decided to finally take the plunge into repairing monitors -- or at least pretend to fix them :rolleyes:

I'm probably beating a dead bloated putrefied horse but I'm trying to narrow down the problem with my G07-CBO 19" on my resurrected Gorf upright. It's a static wave on the upper half of the screen that doesn't oscillate, the picture warps underneath. In the attached photo can someone better explain the problem?

a) horizontal curl
b) hum bar
c) problem with horizontal freq. pot
d) need to check B+
e) none of the above

I installed a capkit from Bob Roberts but I didn't install the C303 sync mod because at the time I didn't think I needed it. I also cleaned the fuse clip and installed new fuses. The screen is now bright and beautiful aside from the wave on the top (or left).

I appreciate the assist!

IMG_1817.jpg IMG_1818.jpg
 
Several things can cause this issue.....first thing....check the monitor's B+

If the B+ is good, what can cause this???

01) the monitor's big filter cap (a lot of times this will drag down the B+, but not always).

02) Filter caps failing on the power supply. Are you running an original linear supply? Are any of the caps bulging, cracking, or oozing at the ends?

03) A whimpy fuse block (regardless of how good you cleaned it)

04) A whimpy power connector....either at the motherboard (the smaller one at the bottom of the card cage) or one at the power supply.

Edward
 
Several things can cause this issue.....first thing....check the monitor's B+

If the B+ is good, what can cause this???

01) the monitor's big filter cap (a lot of times this will drag down the B+, but not always).

02) Filter caps failing on the power supply. Are you running an original linear supply? Are any of the caps bulging, cracking, or oozing at the ends?

03) A whimpy fuse block (regardless of how good you cleaned it)

04) A whimpy power connector....either at the motherboard (the smaller one at the bottom of the card cage) or one at the power supply.

Edward


I capped the linear power supply so I believe I can rule that one out. Thanks for the checklist of ideas, I'll give them all a shot.

ivan
 
So I replaced the fuse block, the flyback, and the B+ filter cap.

The monitor still looks great, but the static wave is still there. I started examining the main pcb assembly closely and I think the linearity coil at L1502 is damaged.

Does any one have an idea on where to get a replacement part?

G07-CBO / L1502 / Linarity Coil / A39835

-- I'm assuming the Midway trouble shooting monitor manual has a typo on "linarity"?


ivanx
 
do youhave another game to plug this monitor up to so you can rule out the monitor itself?

you can get long video cables and hook up to another nearby
game too for an easy test
 
i can give it a shot. however i did hook up a working WG 4900 to my Gorf cab without experiencing the wave problems.

ivan
 
i can give it a shot. however i did hook up a working WG 4900 to my Gorf cab without experiencing the wave problems.

ivan

Sounds like it's a monitor issue then.
 
Ok, I think I know the problem. I believe there is a defective horizontal frequency pot at R504. I accidentally pressed against it harder than I should have and the screen cleared up for few seconds!!

I'm waiting for an order of replacement parts but I'll let everyone know how it works out.
 
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