GO7 rolls horizontally

[Zinfer]

Sorry man, I got held back on Bank Panic G07. The vertical hold is not holding. Very bad. Tried to adjust it out, but I sure could use a Bob Roberts pot kit for this G07. The Twisted Quarter cap kit did not include the 3.3uf50v BP caps for C301/C520. I am thinking these caps are responsible for the vertical hold but I am not at all sure.
So I ordered a good supply of them for my own stock.
This held me up on pulling the G07 from Centipede until I get the last one fixed. So no good pics on it.
However, while I had Bank Panic's G07 pulled I went ahead and replaced the resistors aforementioned. Maybe that should be part of a standard cap kit for a G07.

 

[KenLayton]

C301 is in the beam limiter circuit.

C520 is in the sync circuit.

 

[Zinfer]

C301 is in the beam limiter circuit.

C520 is in the sync circuit.

WOw. Thanks Ken. I don't know what a beam limiter is, but it sounds like 520 is the chief candidate. I don't understand why neither is deemed important by Twisted Quarter.

 

[Buffett]

i include ALL the caps in my G07 cap kit.

the 2 BP caps and the filter cap.

why you would not include 2 of the most important caps for that chassis i will never know.

Peace
Buffett

 

[KenLayton]

These monitors are certainly old enough to have those caps included in the kit. Over the past 3 or 4 years, I've encountered roughly half of those two caps gone bad. If they are not included in a capkit, I have enough extra 3.3 or 4.7 uf @ 50v bi-polar in stock that I automatically replace those caps.

 

[Buffett]

i even stock the 1uf @ 50v BP caps used on the CAO and a few other chassis.

they are not common to allot of chassis but they need to be replaced like all the others.

Peace
Buffett

 

[Zinfer]

Heartily agree. I just placed an order of a lifetime supply (at least for me). I have several G07's and I just can't stomach necessary caps not being replaced. It adds that shadow of doubt to the job that you worked very hard at accomplishing.
Not going to catch me again like that. I absolutely hate installing/removing/installing removing a G07 chassis. Huge waste of time. Now watch - I'll throw these two minor caps in and bam - problem fixed. What a pisser.

 

[Buffett]

lets hope it is an easy fix.

i stock a wide range of caps just so i do not have to wait on an order to come in just to fix 1 chassis.

Peace
Buffett

 

[Zinfer]

Ok, well dumbness strikes. All these years I never bothered to actually look at the hookup. Today I have.
The wires leading to J202. J3, J2, J1.

Examining the connector, the red, J1 is clipped entirely. Follow the wires for J3 and J2.

Hrm, electrical tape to a white wire. Guessing these are all connected to one line. Removed electrical tape.

Yep. Ok, not sure what they were trying to accomplish here. Follow the white wire now.

Dead ends. Looks like for some reason these were ALL cut and then taped back together. WTH is going on here. So there's no sync at all.
Let's take a look at the connector. Hoping there's a wire that is supposed to be sync.

Nothing seems to be out of place or apparent. Now I have to figure out where the Red, Green and orange wire originally came from. I've never had to repin or add pins to a main board connector before. Any docs or diagrams for this? Wondering now if Centipede actually came stock with a G07 or if this was a bad attempt at conversion.

 

[Zinfer]

So I pulled P19 to take a look. Apparently that's where Sync circuits are.
By my wiring list, at 10 (Video Vert. Sync), M (Video Horiz. Sync) and it looks like Video Composite Sync at 12.

So the Video Return is at L (Green/White), Horiz. Sync is at M (Purple/White), Vert. Sync is at 10 (Red/White) and Composite Sync at 12 is absent.

So, wouldn't the Composite Sync go to D1 of J202? I need to know more about the pinout on the G07 J201 to figure out why Sync is going to J201. I looked over a doc on a G07 pinout. But so far I'm only finding J201's.
I'm going to say that all looks ok with J201 and positive sync. But I've always known at least one line going to J202.
Maybe that's just because some used negative sync rather than positive??

 

[Zinfer]

G07 chassis fully recapped, including the 3.3uf50v bp's. Also swapped out the 390 Ohm resistors for brand new. Reflowed the brand new adjustment pots. Nothing seems to make a difference on this (?).
I'm down to looking at the transistors now. It practically has to be a bad transistor. It doesn't even try to hold the image. Thinking it's Transistor x302 or x306.

 

[Zinfer]

Ok, well X301 - X306 have been pulled and replaced.
IC501 pulled, socketed and replaced. Not one change.
Looking at the screen however, I don't understand the text being off to the right.

Throwing in the towel on it for another night.

 

[Buffett]

looks to me like 1 of your sync's from from the PCB is missing.

if you can take a pic of how you have it connected that would be great.
you may not have it connected properly.

you have part of it or you would not have an image.

try and connect a different game up to that monitor and see if the problem follows.

it kinda seems your chasing your tail for no reason.

Peace
Buffett

 

[Zinfer]

Kinda? I just said in the other post I found the problem on the PCB with my Pat. After I find the problem you come to the same conclusion?

 

[Buffett]

Kinda? I just said in the other post I found the problem on the PCB with my Pat. After I find the problem you come to the same conclusion?

i do not remember ever reading the fix in another thread.

all i know is i have seen that problem before.

Peace
Buffett

 

[Zinfer]

Unless I'm totally off base there are two sync chips, both 7407 TTL's at 9a and 10 a/b.
I am hoping that is where the problem is.

 

[smalltownguy2]

Just shooting from the hip here, but you HAVE tested the game's output on another known working monitor, right?

 

[SterlingRush]

Use this thread, you could possibly backwards engineer what is discussed in it. It has pics from a couple of different machines, talking about the positive sync/negative sync boards & cocktail/upright cabs.
http://forums.arcade-museum.com/showthread.php?t=298845

On my cocktail Centipede(negative sync), going to a G07-FBO chassis, I have one composite sync wire leaving the edge connector of the game PCB. It is the purple/white wire in my pics. Mid travel, that one composite sync, gets split into two wires going to the monitor. At J202 connector, J1 & J2 are populated, and tied together, J3 is empty. J201 connecter is: J1 empty, J2 empty, J3 ground, J4 blue signal, J5 green signal, J6 red signal.

Now, if I'm thinking clearly, your upright should be positive sync. With that being said, 1 composite sync from your game PCB, that should split into two wires going to J201 J1 & J2 locations. Again, if I'm thinking straight, your one composite sync should populate J1 & J2 locations. I would try the combined sync at J1 & J2 at J201. If not good, try the combined sync at J1 & J2 of J202.

No idea what they were trying to do, cutting wires, and going all over the place. Something to try, to help rule out, from where all of the video wires are cut and taped:
-Combine your red/white & purple/white from the monitor side red 6 pin connector, to just the purple/white wire on the PCB side.
-Or take the separate 3 pin connector, use it for J202 J1 & J2, splice those two wires to the one purple/white wire.


With all of the work you've done to this chassis, I'm thinking it's that wiring issue.

 

[Torin]

Yes, that was my issue and I have already suggested that he try the opposite sync to see if that fixes it.

Use this thread, you could possibly backwards engineer what is discussed in it. It has pics from a couple of different machines, talking about the positive sync/negative sync boards & cocktail/upright cabs.
http://forums.arcade-museum.com/showthread.php?t=298845

On my cocktail Centipede(negative sync), going to a G07-FBO chassis, I have one composite sync wire leaving the edge connector of the game PCB. It is the purple/white wire in my pics. Mid travel, that one composite sync, gets split into two wires going to the monitor. At J202 connector, J1 & J2 are populated, and tied together, J3 is empty. J201 connecter is: J1 empty, J2 empty, J3 ground, J4 blue signal, J5 green signal, J6 red signal.

Now, if I'm thinking clearly, your upright should be positive sync. With that being said, 1 composite sync from your game PCB, that should split into two wires going to J201 J1 & J2 locations. Again, if I'm thinking straight, your one composite sync should populate J1 & J2 locations. I would try the combined sync at J1 & J2 at J201. If not good, try the combined sync at J1 & J2 of J202.

No idea what they were trying to do, cutting wires, and going all over the place. Something to try, to help rule out, from where all of the video wires are cut and taped:
-Combine your red/white & purple/white from the monitor side red 6 pin connector, to just the purple/white wire on the PCB side.
-Or take the separate 3 pin connector, use it for J202 J1 & J2, splice those two wires to the one purple/white wire.


With all of the work you've done to this chassis, I'm thinking it's that wiring issue.

 

[Zinfer]

Ok, well I will get to that after I get this off the Pat. There is no reason sync should be off on the Pat as well. That tells me it's something on the PCB itself, not in the wiring.