G07 slow vertical rolling - a solution...

modessitt

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I recently repaired a Spy Hunter boardset in the last few weeks, put it in the game, and it worked just fine. A week later, the monitor is slowly rolling vertically. Adjusting the vertical hold and V-Lin pots can make it slow to almost a stop, but it is with a black line down the center and the left side on the right and the right side on the left. Can't get it to lock.

After looking over some previous threads on this issue, it seems others have had this problem and not found a solution:

http://forums.arcade-museum.com/showthread.php?t=207658

http://forums.arcade-museum.com/showthread.php?t=150650

http://forums.arcade-museum.com/showthread.php?t=212534

http://forums.arcade-museum.com/showthread.php?t=211682

Despite a couple mentions of caps, pots, and IC501 helping some people, these people still didn't have a solution.

Well, I fixed this one, and I'll explain how I did so. It helped that I had a known-working G07 on hand, as I could compare readings. If I hadn't had the extra G07, it's likely I would have chased ghosts for quite a while before solving the puzzle.

As anyone with the G07 flowchart knows, a vertical hold issue is pointed towards three parts - Q306, Q302, and IC501. Now, I had previously used my meter to test these three components and all readings seemed to indicate they were fine. However, when I compared these readings to the known good chassis, I found that the reading between the emitter (black lead) and the collector (red lead) of Q302 showed a different reading. The good chassis showed a reading of 1.4xx, while the bad chassis showed a reading of .7xx. This was the only difference between either chassis. Q302 is a C1685 transistor (which I didn't have new) that cross references to an NTE85 (which I did have new), so I replaced it and the image now locks perfectly.

So, if anyone is still fighting this issue, you may want to go check those readings to see if they are off. if I hadn't had the good chassis, I would have assumed the .7xx reading was okay...
 
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I wish that I could bookmark posts on-site; I've got a couple that I've been meaning to get back to, and I don't want to forget this later.
 
I don't have a chassis in front of me, but do you mean C1685? That crosses to an NTE85, but the C1695 crossses to a NTE229 (which I think is the same, just reversed).

edit: Just got my hands on one, and yes, it's a C1685. And there are a ton on there. So, if you have a parts chassis, you could rob one from there, in a pinch.
 
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I don't have a chassis in front of me, but do you mean C1685? That crosses to an NTE85, but the C1695 crossses to a NTE229 (which I think is the same, just reversed).

edit: Just got my hands on one, and yes, it's a C1685. And there are a ton on there. So, if you have a parts chassis, you could rob one from there, in a pinch.

yep, sorry. edited...
 
I wish that I could bookmark posts on-site; I've got a couple that I've been meaning to get back to, and I don't want to forget this later.

You can subscribe to the thread, or even have it send you emails when there are responses.

Once subscribed, go to your USER CP and create a folder for certain subscribed threads you want to especially remember (in case you have it set to auto-subscribe to any thread you reply in like I do). This way you'll be able to find those threads quickly if you need to...

Oh, and you could always open a thread, then create a bookmark in your browser for that page - or click on a post number so that only that post is shown and then bookmark. Going to that bookmark will bring you straight to that thread or post...
 
Okay...so, assuming a standard horizontally-mounted monitor, the scrolling that you're talking about is left-right or right-left, correct?

I was sure that my X302 was bad, based on readings from other chassis; replaced it, and...still scrolling.

But, it has given me incentive to start poking again. I'd shelved this a couple years ago.
 
On a standard horizontally-mounted monitor, vertical scrolling would be top to bottom or bottom to top. Left to right or right to left is a horizontal hold issue. For a horizontal hold issue - besides caps, the pot, and IC501 - check Q301 and Q305...
 
BTW - another trick - especially if it looks like both the horizontal AND vertical hold is off, and you know the sync is connected properly - is to move the ground wire from Pin 4 of the 6-pin connector to Pin 1 of the 3-pin connector. Even if you get continuity between them with a meter, for some reason this move will sometimes solve that issue...
 
Had trouble with a G07 with the case of the slow rolls. I messed with it for months without success....cap kit, new IC, reflowed solder joints, and replaced X302 & X306. So today I thought I'd look at it again and see if I could get it to work....if not it was going to be sold as a parts board.

I used the advice to replace X302 & X306 with the NTE equivalants, but I guess I put them in backwards almost a year ago.

Fast forward to today, I had a parts board that I used for reference and it looked like I installed them backwards. Once I removed the X302 & X306 and reinstalled all is well.

I have to give you guys props! Without this community I would be royally screwed and most likely out of the hobby.
 
This post was helpful. I was refurbing 2 G07s......one would not lock in vertically. Did all the usual adjustments and solder connections. Changed the pots.....still no lock...….then I changed x306 and x302 which let it finally sync up and lock. Thanks.
 
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