G07 h freq not right?... and when I adjust pot things are strange.

damadczar

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G07 h freq not right?... and when I adjust pot things are strange.

Here's what I've got.

Threw a 60in1 in the ms pac while I do some board repair. Keep in mind that this monitor always had a slight downward dip on ms pac as well, but it didn't seem as pronounced.

It comes up kind weird, like the synch isn't right.

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Sometimes it fixes itself, sometimes it doesn't. If it doesn't, and I mess with h.freq I get a picture, but the right side (top if horizontal orientation) dips downward.

photo+5.JPG


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In these pictures, the wave on the right isn't so bad. Sometimes it's been "crazy" like dipping down 1/3 down the screen.

I've previously done a cap kit and flyback from bob roberts (last year), so all that should be okay. Could it be the pots? Something else.

I'll also say that not too long ago the picture was better, but I moved the machine around and it seemed to get wider. That problem plus my pac board going bad prompted me to start repairs.

Steven
 
Thanks Ken.

So you think I just need to replace the H Freq pot?

I let it run for about 2 hours, and just checked on it. The squiggle dip/wave on the right is gone now.... I'm sure b/c it heated up.

Steven
 
Reflow the solder on those pots, while you have the chassis out, wipe the pots. Meaning, turn the pots all the way left and right, quite a few times, so that it cleans the contacts. Install and redial in your monitor, if the problem persists, then you know it's another issue.

Pots could still be good, it may just need solder touched up.
 
Reflow the solder on those pots, while you have the chassis out, wipe the pots. Meaning, turn the pots all the way left and right, quite a few times, so that it cleans the contacts. Install and redial in your monitor, if the problem persists, then you know it's another issue.

Pots could still be good, it may just need solder touched up.

totally this. visually inspect them too though and make sure they're not cracked or something. it's unlikely, just adding that to your list of stuff you need to know. :)
 
Alright, I've done the following:

- Sucked up and re-soldered all the pots and the pathways along that circuit as much as i could (everything that looked bad).

- Re-flowed any other bad looking solder joints

At this point, I tested... No change.

- Took it back off and replaced the h.freq pot with one off a spare board, tested again.

I still get the wavy picture on the right hand side, but I don't have to constantly change the pot anymore to get a clear picture.

Any other ideas? Appreciate the ideas that have come so far.

I inspected all the pots and moved them completely from left to right (except b+, left it where it was). They all looked good.

Steven
 
isn't that what the curl mod is for. to take out that curl on the right side ? Guys I was just wondering because my go7 has the same curl on that side.
 
I did the curl mod when I did my cap kit per Bob Roberts instructions.

I'm thinking that my curl, which isn't much if any on the ms pacman board, is just much worse on the 60in1--especially with a G07--as referenced by these threads:

http://forums.arcade-museum.com/showthread.php?t=269578
http://forums.arcade-museum.com/showthread.php?t=101590&highlight=go7+curl

I did take the advice and measure my B+ after a few minutes warm-up, it was 116VDC.
I adjusted to 120.5VDC, and the curl is much less pronounced.

I'm thinking this is the best I'll get with the 60in1... here's hoping I get my pac board repaired soon. :)

Steven
 
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The 60 in 1 boards have a foldover/curl problem when used with Wells-Gardner and Electrohome monitors. You'll have to live with it or get an LCD monitor.
 
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